//===--- CGStmt.cpp - Emit LLVM Code from Statements ----------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // // This contains code to emit Stmt nodes as LLVM code. // //===----------------------------------------------------------------------===// #include "CGDebugInfo.h" #include "CGOpenMPRuntime.h" #include "CodeGenFunction.h" #include "CodeGenModule.h" #include "TargetInfo.h" #include "clang/AST/Attr.h" #include "clang/AST/StmtVisitor.h" #include "clang/Basic/Builtins.h" #include "clang/Basic/DiagnosticSema.h" #include "clang/Basic/PrettyStackTrace.h" #include "clang/Basic/SourceManager.h" #include "clang/Basic/TargetInfo.h" #include "llvm/ADT/SmallSet.h" #include "llvm/ADT/StringExtras.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/InlineAsm.h" #include "llvm/IR/Intrinsics.h" #include "llvm/IR/MDBuilder.h" #include "llvm/Support/SaveAndRestore.h" using namespace clang; using namespace CodeGen; //===----------------------------------------------------------------------===// // Statement Emission //===----------------------------------------------------------------------===// void CodeGenFunction::EmitStopPoint(const Stmt *S) { if (CGDebugInfo *DI = getDebugInfo()) { SourceLocation Loc; Loc = S->getBeginLoc(); DI->EmitLocation(Builder, Loc); LastStopPoint = Loc; } } void CodeGenFunction::EmitStmt(const Stmt *S, ArrayRef Attrs) { assert(S && "Null statement?"); PGO.setCurrentStmt(S); // These statements have their own debug info handling. if (EmitSimpleStmt(S, Attrs)) return; // Check if we are generating unreachable code. if (!HaveInsertPoint()) { // If so, and the statement doesn't contain a label, then we do not need to // generate actual code. This is safe because (1) the current point is // unreachable, so we don't need to execute the code, and (2) we've already // handled the statements which update internal data structures (like the // local variable map) which could be used by subsequent statements. if (!ContainsLabel(S)) { // Verify that any decl statements were handled as simple, they may be in // scope of subsequent reachable statements. assert(!isa(*S) && "Unexpected DeclStmt!"); return; } // Otherwise, make a new block to hold the code. EnsureInsertPoint(); } // Generate a stoppoint if we are emitting debug info. EmitStopPoint(S); // Ignore all OpenMP directives except for simd if OpenMP with Simd is // enabled. if (getLangOpts().OpenMP && getLangOpts().OpenMPSimd) { if (const auto *D = dyn_cast(S)) { EmitSimpleOMPExecutableDirective(*D); return; } } switch (S->getStmtClass()) { case Stmt::NoStmtClass: case Stmt::CXXCatchStmtClass: case Stmt::SEHExceptStmtClass: case Stmt::SEHFinallyStmtClass: case Stmt::MSDependentExistsStmtClass: llvm_unreachable("invalid statement class to emit generically"); case Stmt::NullStmtClass: case Stmt::CompoundStmtClass: case Stmt::DeclStmtClass: case Stmt::LabelStmtClass: case Stmt::AttributedStmtClass: case Stmt::GotoStmtClass: case Stmt::BreakStmtClass: case Stmt::ContinueStmtClass: case Stmt::DefaultStmtClass: case Stmt::CaseStmtClass: case Stmt::SEHLeaveStmtClass: llvm_unreachable("should have emitted these statements as simple"); #define STMT(Type, Base) #define ABSTRACT_STMT(Op) #define EXPR(Type, Base) \ case Stmt::Type##Class: #include "clang/AST/StmtNodes.inc" { // Remember the block we came in on. llvm::BasicBlock *incoming = Builder.GetInsertBlock(); assert(incoming && "expression emission must have an insertion point"); EmitIgnoredExpr(cast(S)); llvm::BasicBlock *outgoing = Builder.GetInsertBlock(); assert(outgoing && "expression emission cleared block!"); // The expression emitters assume (reasonably!) that the insertion // point is always set. To maintain that, the call-emission code // for noreturn functions has to enter a new block with no // predecessors. We want to kill that block and mark the current // insertion point unreachable in the common case of a call like // "exit();". Since expression emission doesn't otherwise create // blocks with no predecessors, we can just test for that. // However, we must be careful not to do this to our incoming // block, because *statement* emission does sometimes create // reachable blocks which will have no predecessors until later in // the function. This occurs with, e.g., labels that are not // reachable by fallthrough. if (incoming != outgoing && outgoing->use_empty()) { outgoing->eraseFromParent(); Builder.ClearInsertionPoint(); } break; } case Stmt::IndirectGotoStmtClass: EmitIndirectGotoStmt(cast(*S)); break; case Stmt::IfStmtClass: EmitIfStmt(cast(*S)); break; case Stmt::WhileStmtClass: EmitWhileStmt(cast(*S), Attrs); break; case Stmt::DoStmtClass: EmitDoStmt(cast(*S), Attrs); break; case Stmt::ForStmtClass: EmitForStmt(cast(*S), Attrs); break; case Stmt::ReturnStmtClass: EmitReturnStmt(cast(*S)); break; case Stmt::SwitchStmtClass: EmitSwitchStmt(cast(*S)); break; case Stmt::GCCAsmStmtClass: // Intentional fall-through. case Stmt::MSAsmStmtClass: EmitAsmStmt(cast(*S)); break; case Stmt::CoroutineBodyStmtClass: EmitCoroutineBody(cast(*S)); break; case Stmt::CoreturnStmtClass: EmitCoreturnStmt(cast(*S)); break; case Stmt::CapturedStmtClass: { const CapturedStmt *CS = cast(S); EmitCapturedStmt(*CS, CS->getCapturedRegionKind()); } break; case Stmt::ObjCAtTryStmtClass: EmitObjCAtTryStmt(cast(*S)); break; case Stmt::ObjCAtCatchStmtClass: llvm_unreachable( "@catch statements should be handled by EmitObjCAtTryStmt"); case Stmt::ObjCAtFinallyStmtClass: llvm_unreachable( "@finally statements should be handled by EmitObjCAtTryStmt"); case Stmt::ObjCAtThrowStmtClass: EmitObjCAtThrowStmt(cast(*S)); break; case Stmt::ObjCAtSynchronizedStmtClass: EmitObjCAtSynchronizedStmt(cast(*S)); break; case Stmt::ObjCForCollectionStmtClass: EmitObjCForCollectionStmt(cast(*S)); break; case Stmt::ObjCAutoreleasePoolStmtClass: EmitObjCAutoreleasePoolStmt(cast(*S)); break; case Stmt::CXXTryStmtClass: EmitCXXTryStmt(cast(*S)); break; case Stmt::CXXForRangeStmtClass: EmitCXXForRangeStmt(cast(*S), Attrs); break; case Stmt::SEHTryStmtClass: EmitSEHTryStmt(cast(*S)); break; case Stmt::OMPParallelDirectiveClass: EmitOMPParallelDirective(cast(*S)); break; case Stmt::OMPSimdDirectiveClass: EmitOMPSimdDirective(cast(*S)); break; case Stmt::OMPForDirectiveClass: EmitOMPForDirective(cast(*S)); break; case Stmt::OMPForSimdDirectiveClass: EmitOMPForSimdDirective(cast(*S)); break; case Stmt::OMPSectionsDirectiveClass: EmitOMPSectionsDirective(cast(*S)); break; case Stmt::OMPSectionDirectiveClass: EmitOMPSectionDirective(cast(*S)); break; case Stmt::OMPSingleDirectiveClass: EmitOMPSingleDirective(cast(*S)); break; case Stmt::OMPMasterDirectiveClass: EmitOMPMasterDirective(cast(*S)); break; case Stmt::OMPCriticalDirectiveClass: EmitOMPCriticalDirective(cast(*S)); break; case Stmt::OMPParallelForDirectiveClass: EmitOMPParallelForDirective(cast(*S)); break; case Stmt::OMPParallelForSimdDirectiveClass: EmitOMPParallelForSimdDirective(cast(*S)); break; case Stmt::OMPParallelMasterDirectiveClass: EmitOMPParallelMasterDirective(cast(*S)); break; case Stmt::OMPParallelSectionsDirectiveClass: EmitOMPParallelSectionsDirective(cast(*S)); break; case Stmt::OMPTaskDirectiveClass: EmitOMPTaskDirective(cast(*S)); break; case Stmt::OMPTaskyieldDirectiveClass: EmitOMPTaskyieldDirective(cast(*S)); break; case Stmt::OMPBarrierDirectiveClass: EmitOMPBarrierDirective(cast(*S)); break; case Stmt::OMPTaskwaitDirectiveClass: EmitOMPTaskwaitDirective(cast(*S)); break; case Stmt::OMPTaskgroupDirectiveClass: EmitOMPTaskgroupDirective(cast(*S)); break; case Stmt::OMPFlushDirectiveClass: EmitOMPFlushDirective(cast(*S)); break; case Stmt::OMPDepobjDirectiveClass: EmitOMPDepobjDirective(cast(*S)); break; case Stmt::OMPScanDirectiveClass: EmitOMPScanDirective(cast(*S)); break; case Stmt::OMPOrderedDirectiveClass: EmitOMPOrderedDirective(cast(*S)); break; case Stmt::OMPAtomicDirectiveClass: EmitOMPAtomicDirective(cast(*S)); break; case Stmt::OMPTargetDirectiveClass: EmitOMPTargetDirective(cast(*S)); break; case Stmt::OMPTeamsDirectiveClass: EmitOMPTeamsDirective(cast(*S)); break; case Stmt::OMPCancellationPointDirectiveClass: EmitOMPCancellationPointDirective(cast(*S)); break; case Stmt::OMPCancelDirectiveClass: EmitOMPCancelDirective(cast(*S)); break; case Stmt::OMPTargetDataDirectiveClass: EmitOMPTargetDataDirective(cast(*S)); break; case Stmt::OMPTargetEnterDataDirectiveClass: EmitOMPTargetEnterDataDirective(cast(*S)); break; case Stmt::OMPTargetExitDataDirectiveClass: EmitOMPTargetExitDataDirective(cast(*S)); break; case Stmt::OMPTargetParallelDirectiveClass: EmitOMPTargetParallelDirective(cast(*S)); break; case Stmt::OMPTargetParallelForDirectiveClass: EmitOMPTargetParallelForDirective(cast(*S)); break; case Stmt::OMPTaskLoopDirectiveClass: EmitOMPTaskLoopDirective(cast(*S)); break; case Stmt::OMPTaskLoopSimdDirectiveClass: EmitOMPTaskLoopSimdDirective(cast(*S)); break; case Stmt::OMPMasterTaskLoopDirectiveClass: EmitOMPMasterTaskLoopDirective(cast(*S)); break; case Stmt::OMPMasterTaskLoopSimdDirectiveClass: EmitOMPMasterTaskLoopSimdDirective( cast(*S)); break; case Stmt::OMPParallelMasterTaskLoopDirectiveClass: EmitOMPParallelMasterTaskLoopDirective( cast(*S)); break; case Stmt::OMPParallelMasterTaskLoopSimdDirectiveClass: EmitOMPParallelMasterTaskLoopSimdDirective( cast(*S)); break; case Stmt::OMPDistributeDirectiveClass: EmitOMPDistributeDirective(cast(*S)); break; case Stmt::OMPTargetUpdateDirectiveClass: EmitOMPTargetUpdateDirective(cast(*S)); break; case Stmt::OMPDistributeParallelForDirectiveClass: EmitOMPDistributeParallelForDirective( cast(*S)); break; case Stmt::OMPDistributeParallelForSimdDirectiveClass: EmitOMPDistributeParallelForSimdDirective( cast(*S)); break; case Stmt::OMPDistributeSimdDirectiveClass: EmitOMPDistributeSimdDirective(cast(*S)); break; case Stmt::OMPTargetParallelForSimdDirectiveClass: EmitOMPTargetParallelForSimdDirective( cast(*S)); break; case Stmt::OMPTargetSimdDirectiveClass: EmitOMPTargetSimdDirective(cast(*S)); break; case Stmt::OMPTeamsDistributeDirectiveClass: EmitOMPTeamsDistributeDirective(cast(*S)); break; case Stmt::OMPTeamsDistributeSimdDirectiveClass: EmitOMPTeamsDistributeSimdDirective( cast(*S)); break; case Stmt::OMPTeamsDistributeParallelForSimdDirectiveClass: EmitOMPTeamsDistributeParallelForSimdDirective( cast(*S)); break; case Stmt::OMPTeamsDistributeParallelForDirectiveClass: EmitOMPTeamsDistributeParallelForDirective( cast(*S)); break; case Stmt::OMPTargetTeamsDirectiveClass: EmitOMPTargetTeamsDirective(cast(*S)); break; case Stmt::OMPTargetTeamsDistributeDirectiveClass: EmitOMPTargetTeamsDistributeDirective( cast(*S)); break; case Stmt::OMPTargetTeamsDistributeParallelForDirectiveClass: EmitOMPTargetTeamsDistributeParallelForDirective( cast(*S)); break; case Stmt::OMPTargetTeamsDistributeParallelForSimdDirectiveClass: EmitOMPTargetTeamsDistributeParallelForSimdDirective( cast(*S)); break; case Stmt::OMPTargetTeamsDistributeSimdDirectiveClass: EmitOMPTargetTeamsDistributeSimdDirective( cast(*S)); break; } } bool CodeGenFunction::EmitSimpleStmt(const Stmt *S, ArrayRef Attrs) { switch (S->getStmtClass()) { default: return false; case Stmt::NullStmtClass: break; case Stmt::CompoundStmtClass: EmitCompoundStmt(cast(*S)); break; case Stmt::DeclStmtClass: EmitDeclStmt(cast(*S)); break; case Stmt::LabelStmtClass: EmitLabelStmt(cast(*S)); break; case Stmt::AttributedStmtClass: EmitAttributedStmt(cast(*S)); break; case Stmt::GotoStmtClass: EmitGotoStmt(cast(*S)); break; case Stmt::BreakStmtClass: EmitBreakStmt(cast(*S)); break; case Stmt::ContinueStmtClass: EmitContinueStmt(cast(*S)); break; case Stmt::DefaultStmtClass: EmitDefaultStmt(cast(*S), Attrs); break; case Stmt::CaseStmtClass: EmitCaseStmt(cast(*S), Attrs); break; case Stmt::SEHLeaveStmtClass: EmitSEHLeaveStmt(cast(*S)); break; } return true; } /// EmitCompoundStmt - Emit a compound statement {..} node. If GetLast is true, /// this captures the expression result of the last sub-statement and returns it /// (for use by the statement expression extension). Address CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S, bool GetLast, AggValueSlot AggSlot) { PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(), "LLVM IR generation of compound statement ('{}')"); // Keep track of the current cleanup stack depth, including debug scopes. LexicalScope Scope(*this, S.getSourceRange()); return EmitCompoundStmtWithoutScope(S, GetLast, AggSlot); } Address CodeGenFunction::EmitCompoundStmtWithoutScope(const CompoundStmt &S, bool GetLast, AggValueSlot AggSlot) { const Stmt *ExprResult = S.getStmtExprResult(); assert((!GetLast || (GetLast && ExprResult)) && "If GetLast is true then the CompoundStmt must have a StmtExprResult"); Address RetAlloca = Address::invalid(); for (auto *CurStmt : S.body()) { if (GetLast && ExprResult == CurStmt) { // We have to special case labels here. They are statements, but when put // at the end of a statement expression, they yield the value of their // subexpression. Handle this by walking through all labels we encounter, // emitting them before we evaluate the subexpr. // Similar issues arise for attributed statements. while (!isa(ExprResult)) { if (const auto *LS = dyn_cast(ExprResult)) { EmitLabel(LS->getDecl()); ExprResult = LS->getSubStmt(); } else if (const auto *AS = dyn_cast(ExprResult)) { // FIXME: Update this if we ever have attributes that affect the // semantics of an expression. ExprResult = AS->getSubStmt(); } else { llvm_unreachable("unknown value statement"); } } EnsureInsertPoint(); const Expr *E = cast(ExprResult); QualType ExprTy = E->getType(); if (hasAggregateEvaluationKind(ExprTy)) { EmitAggExpr(E, AggSlot); } else { // We can't return an RValue here because there might be cleanups at // the end of the StmtExpr. Because of that, we have to emit the result // here into a temporary alloca. RetAlloca = CreateMemTemp(ExprTy); EmitAnyExprToMem(E, RetAlloca, Qualifiers(), /*IsInit*/ false); } } else { EmitStmt(CurStmt); } } return RetAlloca; } void CodeGenFunction::SimplifyForwardingBlocks(llvm::BasicBlock *BB) { llvm::BranchInst *BI = dyn_cast(BB->getTerminator()); // If there is a cleanup stack, then we it isn't worth trying to // simplify this block (we would need to remove it from the scope map // and cleanup entry). if (!EHStack.empty()) return; // Can only simplify direct branches. if (!BI || !BI->isUnconditional()) return; // Can only simplify empty blocks. if (BI->getIterator() != BB->begin()) return; BB->replaceAllUsesWith(BI->getSuccessor(0)); BI->eraseFromParent(); BB->eraseFromParent(); } void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB, bool IsFinished) { llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); // Fall out of the current block (if necessary). EmitBranch(BB); if (IsFinished && BB->use_empty()) { delete BB; return; } // Place the block after the current block, if possible, or else at // the end of the function. if (CurBB && CurBB->getParent()) CurFn->getBasicBlockList().insertAfter(CurBB->getIterator(), BB); else CurFn->getBasicBlockList().push_back(BB); Builder.SetInsertPoint(BB); } void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) { // Emit a branch from the current block to the target one if this // was a real block. If this was just a fall-through block after a // terminator, don't emit it. llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); if (!CurBB || CurBB->getTerminator()) { // If there is no insert point or the previous block is already // terminated, don't touch it. } else { // Otherwise, create a fall-through branch. Builder.CreateBr(Target); } Builder.ClearInsertionPoint(); } void CodeGenFunction::EmitBlockAfterUses(llvm::BasicBlock *block) { bool inserted = false; for (llvm::User *u : block->users()) { if (llvm::Instruction *insn = dyn_cast(u)) { CurFn->getBasicBlockList().insertAfter(insn->getParent()->getIterator(), block); inserted = true; break; } } if (!inserted) CurFn->getBasicBlockList().push_back(block); Builder.SetInsertPoint(block); } CodeGenFunction::JumpDest CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) { JumpDest &Dest = LabelMap[D]; if (Dest.isValid()) return Dest; // Create, but don't insert, the new block. Dest = JumpDest(createBasicBlock(D->getName()), EHScopeStack::stable_iterator::invalid(), NextCleanupDestIndex++); return Dest; } void CodeGenFunction::EmitLabel(const LabelDecl *D) { // Add this label to the current lexical scope if we're within any // normal cleanups. Jumps "in" to this label --- when permitted by // the language --- may need to be routed around such cleanups. if (EHStack.hasNormalCleanups() && CurLexicalScope) CurLexicalScope->addLabel(D); JumpDest &Dest = LabelMap[D]; // If we didn't need a forward reference to this label, just go // ahead and create a destination at the current scope. if (!Dest.isValid()) { Dest = getJumpDestInCurrentScope(D->getName()); // Otherwise, we need to give this label a target depth and remove // it from the branch-fixups list. } else { assert(!Dest.getScopeDepth().isValid() && "already emitted label!"); Dest.setScopeDepth(EHStack.stable_begin()); ResolveBranchFixups(Dest.getBlock()); } EmitBlock(Dest.getBlock()); // Emit debug info for labels. if (CGDebugInfo *DI = getDebugInfo()) { if (CGM.getCodeGenOpts().hasReducedDebugInfo()) { DI->setLocation(D->getLocation()); DI->EmitLabel(D, Builder); } } incrementProfileCounter(D->getStmt()); } /// Change the cleanup scope of the labels in this lexical scope to /// match the scope of the enclosing context. void CodeGenFunction::LexicalScope::rescopeLabels() { assert(!Labels.empty()); EHScopeStack::stable_iterator innermostScope = CGF.EHStack.getInnermostNormalCleanup(); // Change the scope depth of all the labels. for (SmallVectorImpl::const_iterator i = Labels.begin(), e = Labels.end(); i != e; ++i) { assert(CGF.LabelMap.count(*i)); JumpDest &dest = CGF.LabelMap.find(*i)->second; assert(dest.getScopeDepth().isValid()); assert(innermostScope.encloses(dest.getScopeDepth())); dest.setScopeDepth(innermostScope); } // Reparent the labels if the new scope also has cleanups. if (innermostScope != EHScopeStack::stable_end() && ParentScope) { ParentScope->Labels.append(Labels.begin(), Labels.end()); } } void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) { EmitLabel(S.getDecl()); EmitStmt(S.getSubStmt()); } void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) { bool nomerge = false; for (const auto *A : S.getAttrs()) if (A->getKind() == attr::NoMerge) { nomerge = true; break; } SaveAndRestore save_nomerge(InNoMergeAttributedStmt, nomerge); EmitStmt(S.getSubStmt(), S.getAttrs()); } void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) { // If this code is reachable then emit a stop point (if generating // debug info). We have to do this ourselves because we are on the // "simple" statement path. if (HaveInsertPoint()) EmitStopPoint(&S); EmitBranchThroughCleanup(getJumpDestForLabel(S.getLabel())); } void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) { if (const LabelDecl *Target = S.getConstantTarget()) { EmitBranchThroughCleanup(getJumpDestForLabel(Target)); return; } // Ensure that we have an i8* for our PHI node. llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()), Int8PtrTy, "addr"); llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); // Get the basic block for the indirect goto. llvm::BasicBlock *IndGotoBB = GetIndirectGotoBlock(); // The first instruction in the block has to be the PHI for the switch dest, // add an entry for this branch. cast(IndGotoBB->begin())->addIncoming(V, CurBB); EmitBranch(IndGotoBB); } void CodeGenFunction::EmitIfStmt(const IfStmt &S) { // C99 6.8.4.1: The first substatement is executed if the expression compares // unequal to 0. The condition must be a scalar type. LexicalScope ConditionScope(*this, S.getCond()->getSourceRange()); if (S.getInit()) EmitStmt(S.getInit()); if (S.getConditionVariable()) EmitDecl(*S.getConditionVariable()); // If the condition constant folds and can be elided, try to avoid emitting // the condition and the dead arm of the if/else. bool CondConstant; if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant, S.isConstexpr())) { // Figure out which block (then or else) is executed. const Stmt *Executed = S.getThen(); const Stmt *Skipped = S.getElse(); if (!CondConstant) // Condition false? std::swap(Executed, Skipped); // If the skipped block has no labels in it, just emit the executed block. // This avoids emitting dead code and simplifies the CFG substantially. if (S.isConstexpr() || !ContainsLabel(Skipped)) { if (CondConstant) incrementProfileCounter(&S); if (Executed) { RunCleanupsScope ExecutedScope(*this); EmitStmt(Executed); } return; } } // Otherwise, the condition did not fold, or we couldn't elide it. Just emit // the conditional branch. llvm::BasicBlock *ThenBlock = createBasicBlock("if.then"); llvm::BasicBlock *ContBlock = createBasicBlock("if.end"); llvm::BasicBlock *ElseBlock = ContBlock; if (S.getElse()) ElseBlock = createBasicBlock("if.else"); // Prefer the PGO based weights over the likelihood attribute. // When the build isn't optimized the metadata isn't used, so don't generate // it. Stmt::Likelihood LH = Stmt::LH_None; uint64_t Count = getProfileCount(S.getThen()); if (!Count && CGM.getCodeGenOpts().OptimizationLevel) LH = Stmt::getLikelihood(S.getThen(), S.getElse()); EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock, Count, LH); // Emit the 'then' code. EmitBlock(ThenBlock); incrementProfileCounter(&S); { RunCleanupsScope ThenScope(*this); EmitStmt(S.getThen()); } EmitBranch(ContBlock); // Emit the 'else' code if present. if (const Stmt *Else = S.getElse()) { { // There is no need to emit line number for an unconditional branch. auto NL = ApplyDebugLocation::CreateEmpty(*this); EmitBlock(ElseBlock); } { RunCleanupsScope ElseScope(*this); EmitStmt(Else); } { // There is no need to emit line number for an unconditional branch. auto NL = ApplyDebugLocation::CreateEmpty(*this); EmitBranch(ContBlock); } } // Emit the continuation block for code after the if. EmitBlock(ContBlock, true); } void CodeGenFunction::EmitWhileStmt(const WhileStmt &S, ArrayRef WhileAttrs) { // Emit the header for the loop, which will also become // the continue target. JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond"); EmitBlock(LoopHeader.getBlock()); // Create an exit block for when the condition fails, which will // also become the break target. JumpDest LoopExit = getJumpDestInCurrentScope("while.end"); // Store the blocks to use for break and continue. BreakContinueStack.push_back(BreakContinue(LoopExit, LoopHeader)); // C++ [stmt.while]p2: // When the condition of a while statement is a declaration, the // scope of the variable that is declared extends from its point // of declaration (3.3.2) to the end of the while statement. // [...] // The object created in a condition is destroyed and created // with each iteration of the loop. RunCleanupsScope ConditionScope(*this); if (S.getConditionVariable()) EmitDecl(*S.getConditionVariable()); // Evaluate the conditional in the while header. C99 6.8.5.1: The // evaluation of the controlling expression takes place before each // execution of the loop body. llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond()); // while(1) is common, avoid extra exit blocks. Be sure // to correctly handle break/continue though. bool EmitBoolCondBranch = true; bool LoopMustProgress = false; if (llvm::ConstantInt *C = dyn_cast(BoolCondVal)) { if (C->isOne()) { EmitBoolCondBranch = false; FnIsMustProgress = false; } } else if (LanguageRequiresProgress()) LoopMustProgress = true; const SourceRange &R = S.getSourceRange(); LoopStack.push(LoopHeader.getBlock(), CGM.getContext(), CGM.getCodeGenOpts(), WhileAttrs, SourceLocToDebugLoc(R.getBegin()), SourceLocToDebugLoc(R.getEnd()), LoopMustProgress); // As long as the condition is true, go to the loop body. llvm::BasicBlock *LoopBody = createBasicBlock("while.body"); if (EmitBoolCondBranch) { llvm::BasicBlock *ExitBlock = LoopExit.getBlock(); if (ConditionScope.requiresCleanups()) ExitBlock = createBasicBlock("while.exit"); llvm::MDNode *Weights = createProfileOrBranchWeightsForLoop( S.getCond(), getProfileCount(S.getBody()), S.getBody()); Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock, Weights); if (ExitBlock != LoopExit.getBlock()) { EmitBlock(ExitBlock); EmitBranchThroughCleanup(LoopExit); } } else if (const Attr *A = Stmt::getLikelihoodAttr(S.getBody())) { CGM.getDiags().Report(A->getLocation(), diag::warn_attribute_has_no_effect_on_infinite_loop) << A << A->getRange(); CGM.getDiags().Report( S.getWhileLoc(), diag::note_attribute_has_no_effect_on_infinite_loop_here) << SourceRange(S.getWhileLoc(), S.getRParenLoc()); } // Emit the loop body. We have to emit this in a cleanup scope // because it might be a singleton DeclStmt. { RunCleanupsScope BodyScope(*this); EmitBlock(LoopBody); incrementProfileCounter(&S); EmitStmt(S.getBody()); } BreakContinueStack.pop_back(); // Immediately force cleanup. ConditionScope.ForceCleanup(); EmitStopPoint(&S); // Branch to the loop header again. EmitBranch(LoopHeader.getBlock()); LoopStack.pop(); // Emit the exit block. EmitBlock(LoopExit.getBlock(), true); // The LoopHeader typically is just a branch if we skipped emitting // a branch, try to erase it. if (!EmitBoolCondBranch) SimplifyForwardingBlocks(LoopHeader.getBlock()); } void CodeGenFunction::EmitDoStmt(const DoStmt &S, ArrayRef DoAttrs) { JumpDest LoopExit = getJumpDestInCurrentScope("do.end"); JumpDest LoopCond = getJumpDestInCurrentScope("do.cond"); uint64_t ParentCount = getCurrentProfileCount(); // Store the blocks to use for break and continue. BreakContinueStack.push_back(BreakContinue(LoopExit, LoopCond)); // Emit the body of the loop. llvm::BasicBlock *LoopBody = createBasicBlock("do.body"); EmitBlockWithFallThrough(LoopBody, &S); { RunCleanupsScope BodyScope(*this); EmitStmt(S.getBody()); } EmitBlock(LoopCond.getBlock()); // C99 6.8.5.2: "The evaluation of the controlling expression takes place // after each execution of the loop body." // Evaluate the conditional in the while header. // C99 6.8.5p2/p4: The first substatement is executed if the expression // compares unequal to 0. The condition must be a scalar type. llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond()); BreakContinueStack.pop_back(); // "do {} while (0)" is common in macros, avoid extra blocks. Be sure // to correctly handle break/continue though. bool EmitBoolCondBranch = true; bool LoopMustProgress = false; if (llvm::ConstantInt *C = dyn_cast(BoolCondVal)) { if (C->isZero()) EmitBoolCondBranch = false; else if (C->isOne()) FnIsMustProgress = false; } else if (LanguageRequiresProgress()) LoopMustProgress = true; const SourceRange &R = S.getSourceRange(); LoopStack.push(LoopBody, CGM.getContext(), CGM.getCodeGenOpts(), DoAttrs, SourceLocToDebugLoc(R.getBegin()), SourceLocToDebugLoc(R.getEnd()), LoopMustProgress); // As long as the condition is true, iterate the loop. if (EmitBoolCondBranch) { uint64_t BackedgeCount = getProfileCount(S.getBody()) - ParentCount; Builder.CreateCondBr( BoolCondVal, LoopBody, LoopExit.getBlock(), createProfileWeightsForLoop(S.getCond(), BackedgeCount)); } LoopStack.pop(); // Emit the exit block. EmitBlock(LoopExit.getBlock()); // The DoCond block typically is just a branch if we skipped // emitting a branch, try to erase it. if (!EmitBoolCondBranch) SimplifyForwardingBlocks(LoopCond.getBlock()); } void CodeGenFunction::EmitForStmt(const ForStmt &S, ArrayRef ForAttrs) { JumpDest LoopExit = getJumpDestInCurrentScope("for.end"); LexicalScope ForScope(*this, S.getSourceRange()); // Evaluate the first part before the loop. if (S.getInit()) EmitStmt(S.getInit()); // Start the loop with a block that tests the condition. // If there's an increment, the continue scope will be overwritten // later. JumpDest Continue = getJumpDestInCurrentScope("for.cond"); llvm::BasicBlock *CondBlock = Continue.getBlock(); EmitBlock(CondBlock); bool LoopMustProgress = false; Expr::EvalResult Result; if (LanguageRequiresProgress()) { if (!S.getCond()) { FnIsMustProgress = false; } else if (!S.getCond()->EvaluateAsInt(Result, getContext())) { LoopMustProgress = true; } } const SourceRange &R = S.getSourceRange(); LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs, SourceLocToDebugLoc(R.getBegin()), SourceLocToDebugLoc(R.getEnd()), LoopMustProgress); // If the for loop doesn't have an increment we can just use the // condition as the continue block. Otherwise we'll need to create // a block for it (in the current scope, i.e. in the scope of the // condition), and that we will become our continue block. if (S.getInc()) Continue = getJumpDestInCurrentScope("for.inc"); // Store the blocks to use for break and continue. BreakContinueStack.push_back(BreakContinue(LoopExit, Continue)); // Create a cleanup scope for the condition variable cleanups. LexicalScope ConditionScope(*this, S.getSourceRange()); if (S.getCond()) { // If the for statement has a condition scope, emit the local variable // declaration. if (S.getConditionVariable()) { EmitDecl(*S.getConditionVariable()); } llvm::BasicBlock *ExitBlock = LoopExit.getBlock(); // If there are any cleanups between here and the loop-exit scope, // create a block to stage a loop exit along. if (ForScope.requiresCleanups()) ExitBlock = createBasicBlock("for.cond.cleanup"); // As long as the condition is true, iterate the loop. llvm::BasicBlock *ForBody = createBasicBlock("for.body"); // C99 6.8.5p2/p4: The first substatement is executed if the expression // compares unequal to 0. The condition must be a scalar type. llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond()); llvm::MDNode *Weights = createProfileOrBranchWeightsForLoop( S.getCond(), getProfileCount(S.getBody()), S.getBody()); if (llvm::ConstantInt *C = dyn_cast(BoolCondVal)) if (C->isOne()) FnIsMustProgress = false; Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights); if (ExitBlock != LoopExit.getBlock()) { EmitBlock(ExitBlock); EmitBranchThroughCleanup(LoopExit); } EmitBlock(ForBody); } else { // Treat it as a non-zero constant. Don't even create a new block for the // body, just fall into it. } incrementProfileCounter(&S); { // Create a separate cleanup scope for the body, in case it is not // a compound statement. RunCleanupsScope BodyScope(*this); EmitStmt(S.getBody()); } // If there is an increment, emit it next. if (S.getInc()) { EmitBlock(Continue.getBlock()); EmitStmt(S.getInc()); } BreakContinueStack.pop_back(); ConditionScope.ForceCleanup(); EmitStopPoint(&S); EmitBranch(CondBlock); ForScope.ForceCleanup(); LoopStack.pop(); // Emit the fall-through block. EmitBlock(LoopExit.getBlock(), true); } void CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S, ArrayRef ForAttrs) { JumpDest LoopExit = getJumpDestInCurrentScope("for.end"); LexicalScope ForScope(*this, S.getSourceRange()); // Evaluate the first pieces before the loop. if (S.getInit()) EmitStmt(S.getInit()); EmitStmt(S.getRangeStmt()); EmitStmt(S.getBeginStmt()); EmitStmt(S.getEndStmt()); // Start the loop with a block that tests the condition. // If there's an increment, the continue scope will be overwritten // later. llvm::BasicBlock *CondBlock = createBasicBlock("for.cond"); EmitBlock(CondBlock); const SourceRange &R = S.getSourceRange(); LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs, SourceLocToDebugLoc(R.getBegin()), SourceLocToDebugLoc(R.getEnd())); // If there are any cleanups between here and the loop-exit scope, // create a block to stage a loop exit along. llvm::BasicBlock *ExitBlock = LoopExit.getBlock(); if (ForScope.requiresCleanups()) ExitBlock = createBasicBlock("for.cond.cleanup"); // The loop body, consisting of the specified body and the loop variable. llvm::BasicBlock *ForBody = createBasicBlock("for.body"); // The body is executed if the expression, contextually converted // to bool, is true. llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond()); llvm::MDNode *Weights = createProfileOrBranchWeightsForLoop( S.getCond(), getProfileCount(S.getBody()), S.getBody()); Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights); if (ExitBlock != LoopExit.getBlock()) { EmitBlock(ExitBlock); EmitBranchThroughCleanup(LoopExit); } EmitBlock(ForBody); incrementProfileCounter(&S); // Create a block for the increment. In case of a 'continue', we jump there. JumpDest Continue = getJumpDestInCurrentScope("for.inc"); // Store the blocks to use for break and continue. BreakContinueStack.push_back(BreakContinue(LoopExit, Continue)); { // Create a separate cleanup scope for the loop variable and body. LexicalScope BodyScope(*this, S.getSourceRange()); EmitStmt(S.getLoopVarStmt()); EmitStmt(S.getBody()); } EmitStopPoint(&S); // If there is an increment, emit it next. EmitBlock(Continue.getBlock()); EmitStmt(S.getInc()); BreakContinueStack.pop_back(); EmitBranch(CondBlock); ForScope.ForceCleanup(); LoopStack.pop(); // Emit the fall-through block. EmitBlock(LoopExit.getBlock(), true); } void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) { if (RV.isScalar()) { Builder.CreateStore(RV.getScalarVal(), ReturnValue); } else if (RV.isAggregate()) { LValue Dest = MakeAddrLValue(ReturnValue, Ty); LValue Src = MakeAddrLValue(RV.getAggregateAddress(), Ty); EmitAggregateCopy(Dest, Src, Ty, getOverlapForReturnValue()); } else { EmitStoreOfComplex(RV.getComplexVal(), MakeAddrLValue(ReturnValue, Ty), /*init*/ true); } EmitBranchThroughCleanup(ReturnBlock); } namespace { // RAII struct used to save and restore a return statment's result expression. struct SaveRetExprRAII { SaveRetExprRAII(const Expr *RetExpr, CodeGenFunction &CGF) : OldRetExpr(CGF.RetExpr), CGF(CGF) { CGF.RetExpr = RetExpr; } ~SaveRetExprRAII() { CGF.RetExpr = OldRetExpr; } const Expr *OldRetExpr; CodeGenFunction &CGF; }; } // namespace /// EmitReturnStmt - Note that due to GCC extensions, this can have an operand /// if the function returns void, or may be missing one if the function returns /// non-void. Fun stuff :). void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) { if (requiresReturnValueCheck()) { llvm::Constant *SLoc = EmitCheckSourceLocation(S.getBeginLoc()); auto *SLocPtr = new llvm::GlobalVariable(CGM.getModule(), SLoc->getType(), false, llvm::GlobalVariable::PrivateLinkage, SLoc); SLocPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global); CGM.getSanitizerMetadata()->disableSanitizerForGlobal(SLocPtr); assert(ReturnLocation.isValid() && "No valid return location"); Builder.CreateStore(Builder.CreateBitCast(SLocPtr, Int8PtrTy), ReturnLocation); } // Returning from an outlined SEH helper is UB, and we already warn on it. if (IsOutlinedSEHHelper) { Builder.CreateUnreachable(); Builder.ClearInsertionPoint(); } // Emit the result value, even if unused, to evaluate the side effects. const Expr *RV = S.getRetValue(); // Record the result expression of the return statement. The recorded // expression is used to determine whether a block capture's lifetime should // end at the end of the full expression as opposed to the end of the scope // enclosing the block expression. // // This permits a small, easily-implemented exception to our over-conservative // rules about not jumping to statements following block literals with // non-trivial cleanups. SaveRetExprRAII SaveRetExpr(RV, *this); RunCleanupsScope cleanupScope(*this); if (const auto *EWC = dyn_cast_or_null(RV)) RV = EWC->getSubExpr(); // FIXME: Clean this up by using an LValue for ReturnTemp, // EmitStoreThroughLValue, and EmitAnyExpr. // Check if the NRVO candidate was not globalized in OpenMP mode. if (getLangOpts().ElideConstructors && S.getNRVOCandidate() && S.getNRVOCandidate()->isNRVOVariable() && (!getLangOpts().OpenMP || !CGM.getOpenMPRuntime() .getAddressOfLocalVariable(*this, S.getNRVOCandidate()) .isValid())) { // Apply the named return value optimization for this return statement, // which means doing nothing: the appropriate result has already been // constructed into the NRVO variable. // If there is an NRVO flag for this variable, set it to 1 into indicate // that the cleanup code should not destroy the variable. if (llvm::Value *NRVOFlag = NRVOFlags[S.getNRVOCandidate()]) Builder.CreateFlagStore(Builder.getTrue(), NRVOFlag); } else if (!ReturnValue.isValid() || (RV && RV->getType()->isVoidType())) { // Make sure not to return anything, but evaluate the expression // for side effects. if (RV) EmitAnyExpr(RV); } else if (!RV) { // Do nothing (return value is left uninitialized) } else if (FnRetTy->isReferenceType()) { // If this function returns a reference, take the address of the expression // rather than the value. RValue Result = EmitReferenceBindingToExpr(RV); Builder.CreateStore(Result.getScalarVal(), ReturnValue); } else { switch (getEvaluationKind(RV->getType())) { case TEK_Scalar: Builder.CreateStore(EmitScalarExpr(RV), ReturnValue); break; case TEK_Complex: EmitComplexExprIntoLValue(RV, MakeAddrLValue(ReturnValue, RV->getType()), /*isInit*/ true); break; case TEK_Aggregate: EmitAggExpr(RV, AggValueSlot::forAddr( ReturnValue, Qualifiers(), AggValueSlot::IsDestructed, AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased, getOverlapForReturnValue())); break; } } ++NumReturnExprs; if (!RV || RV->isEvaluatable(getContext())) ++NumSimpleReturnExprs; cleanupScope.ForceCleanup(); EmitBranchThroughCleanup(ReturnBlock); } void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) { // As long as debug info is modeled with instructions, we have to ensure we // have a place to insert here and write the stop point here. if (HaveInsertPoint()) EmitStopPoint(&S); for (const auto *I : S.decls()) EmitDecl(*I); } void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) { assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!"); // If this code is reachable then emit a stop point (if generating // debug info). We have to do this ourselves because we are on the // "simple" statement path. if (HaveInsertPoint()) EmitStopPoint(&S); EmitBranchThroughCleanup(BreakContinueStack.back().BreakBlock); } void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) { assert(!BreakContinueStack.empty() && "continue stmt not in a loop!"); // If this code is reachable then emit a stop point (if generating // debug info). We have to do this ourselves because we are on the // "simple" statement path. if (HaveInsertPoint()) EmitStopPoint(&S); EmitBranchThroughCleanup(BreakContinueStack.back().ContinueBlock); } /// EmitCaseStmtRange - If case statement range is not too big then /// add multiple cases to switch instruction, one for each value within /// the range. If range is too big then emit "if" condition check. void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S, ArrayRef Attrs) { assert(S.getRHS() && "Expected RHS value in CaseStmt"); llvm::APSInt LHS = S.getLHS()->EvaluateKnownConstInt(getContext()); llvm::APSInt RHS = S.getRHS()->EvaluateKnownConstInt(getContext()); // Emit the code for this case. We do this first to make sure it is // properly chained from our predecessor before generating the // switch machinery to enter this block. llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb"); EmitBlockWithFallThrough(CaseDest, &S); EmitStmt(S.getSubStmt()); // If range is empty, do nothing. if (LHS.isSigned() ? RHS.slt(LHS) : RHS.ult(LHS)) return; Stmt::Likelihood LH = Stmt::getLikelihood(Attrs); llvm::APInt Range = RHS - LHS; // FIXME: parameters such as this should not be hardcoded. if (Range.ult(llvm::APInt(Range.getBitWidth(), 64))) { // Range is small enough to add multiple switch instruction cases. uint64_t Total = getProfileCount(&S); unsigned NCases = Range.getZExtValue() + 1; // We only have one region counter for the entire set of cases here, so we // need to divide the weights evenly between the generated cases, ensuring // that the total weight is preserved. E.g., a weight of 5 over three cases // will be distributed as weights of 2, 2, and 1. uint64_t Weight = Total / NCases, Rem = Total % NCases; for (unsigned I = 0; I != NCases; ++I) { if (SwitchWeights) SwitchWeights->push_back(Weight + (Rem ? 1 : 0)); else if (SwitchLikelihood) SwitchLikelihood->push_back(LH); if (Rem) Rem--; SwitchInsn->addCase(Builder.getInt(LHS), CaseDest); ++LHS; } return; } // The range is too big. Emit "if" condition into a new block, // making sure to save and restore the current insertion point. llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock(); // Push this test onto the chain of range checks (which terminates // in the default basic block). The switch's default will be changed // to the top of this chain after switch emission is complete. llvm::BasicBlock *FalseDest = CaseRangeBlock; CaseRangeBlock = createBasicBlock("sw.caserange"); CurFn->getBasicBlockList().push_back(CaseRangeBlock); Builder.SetInsertPoint(CaseRangeBlock); // Emit range check. llvm::Value *Diff = Builder.CreateSub(SwitchInsn->getCondition(), Builder.getInt(LHS)); llvm::Value *Cond = Builder.CreateICmpULE(Diff, Builder.getInt(Range), "inbounds"); llvm::MDNode *Weights = nullptr; if (SwitchWeights) { uint64_t ThisCount = getProfileCount(&S); uint64_t DefaultCount = (*SwitchWeights)[0]; Weights = createProfileWeights(ThisCount, DefaultCount); // Since we're chaining the switch default through each large case range, we // need to update the weight for the default, ie, the first case, to include // this case. (*SwitchWeights)[0] += ThisCount; } else if (SwitchLikelihood) Weights = createBranchWeights(LH); Builder.CreateCondBr(Cond, CaseDest, FalseDest, Weights); // Restore the appropriate insertion point. if (RestoreBB) Builder.SetInsertPoint(RestoreBB); else Builder.ClearInsertionPoint(); } void CodeGenFunction::EmitCaseStmt(const CaseStmt &S, ArrayRef Attrs) { // If there is no enclosing switch instance that we're aware of, then this // case statement and its block can be elided. This situation only happens // when we've constant-folded the switch, are emitting the constant case, // and part of the constant case includes another case statement. For // instance: switch (4) { case 4: do { case 5: } while (1); } if (!SwitchInsn) { EmitStmt(S.getSubStmt()); return; } // Handle case ranges. if (S.getRHS()) { EmitCaseStmtRange(S, Attrs); return; } llvm::ConstantInt *CaseVal = Builder.getInt(S.getLHS()->EvaluateKnownConstInt(getContext())); if (SwitchLikelihood) SwitchLikelihood->push_back(Stmt::getLikelihood(Attrs)); // If the body of the case is just a 'break', try to not emit an empty block. // If we're profiling or we're not optimizing, leave the block in for better // debug and coverage analysis. if (!CGM.getCodeGenOpts().hasProfileClangInstr() && CGM.getCodeGenOpts().OptimizationLevel > 0 && isa(S.getSubStmt())) { JumpDest Block = BreakContinueStack.back().BreakBlock; // Only do this optimization if there are no cleanups that need emitting. if (isObviouslyBranchWithoutCleanups(Block)) { if (SwitchWeights) SwitchWeights->push_back(getProfileCount(&S)); SwitchInsn->addCase(CaseVal, Block.getBlock()); // If there was a fallthrough into this case, make sure to redirect it to // the end of the switch as well. if (Builder.GetInsertBlock()) { Builder.CreateBr(Block.getBlock()); Builder.ClearInsertionPoint(); } return; } } llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb"); EmitBlockWithFallThrough(CaseDest, &S); if (SwitchWeights) SwitchWeights->push_back(getProfileCount(&S)); SwitchInsn->addCase(CaseVal, CaseDest); // Recursively emitting the statement is acceptable, but is not wonderful for // code where we have many case statements nested together, i.e.: // case 1: // case 2: // case 3: etc. // Handling this recursively will create a new block for each case statement // that falls through to the next case which is IR intensive. It also causes // deep recursion which can run into stack depth limitations. Handle // sequential non-range case statements specially. // // TODO When the next case has a likelihood attribute the code returns to the // recursive algorithm. Maybe improve this case if it becomes common practice // to use a lot of attributes. const CaseStmt *CurCase = &S; const CaseStmt *NextCase = dyn_cast(S.getSubStmt()); // Otherwise, iteratively add consecutive cases to this switch stmt. while (NextCase && NextCase->getRHS() == nullptr) { CurCase = NextCase; llvm::ConstantInt *CaseVal = Builder.getInt(CurCase->getLHS()->EvaluateKnownConstInt(getContext())); if (SwitchWeights) SwitchWeights->push_back(getProfileCount(NextCase)); if (CGM.getCodeGenOpts().hasProfileClangInstr()) { CaseDest = createBasicBlock("sw.bb"); EmitBlockWithFallThrough(CaseDest, CurCase); } // Since this loop is only executed when the CaseStmt has no attributes // use a hard-coded value. if (SwitchLikelihood) SwitchLikelihood->push_back(Stmt::LH_None); SwitchInsn->addCase(CaseVal, CaseDest); NextCase = dyn_cast(CurCase->getSubStmt()); } // Normal default recursion for non-cases. EmitStmt(CurCase->getSubStmt()); } void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S, ArrayRef Attrs) { // If there is no enclosing switch instance that we're aware of, then this // default statement can be elided. This situation only happens when we've // constant-folded the switch. if (!SwitchInsn) { EmitStmt(S.getSubStmt()); return; } llvm::BasicBlock *DefaultBlock = SwitchInsn->getDefaultDest(); assert(DefaultBlock->empty() && "EmitDefaultStmt: Default block already defined?"); if (SwitchLikelihood) SwitchLikelihood->front() = Stmt::getLikelihood(Attrs); EmitBlockWithFallThrough(DefaultBlock, &S); EmitStmt(S.getSubStmt()); } /// CollectStatementsForCase - Given the body of a 'switch' statement and a /// constant value that is being switched on, see if we can dead code eliminate /// the body of the switch to a simple series of statements to emit. Basically, /// on a switch (5) we want to find these statements: /// case 5: /// printf(...); <-- /// ++i; <-- /// break; /// /// and add them to the ResultStmts vector. If it is unsafe to do this /// transformation (for example, one of the elided statements contains a label /// that might be jumped to), return CSFC_Failure. If we handled it and 'S' /// should include statements after it (e.g. the printf() line is a substmt of /// the case) then return CSFC_FallThrough. If we handled it and found a break /// statement, then return CSFC_Success. /// /// If Case is non-null, then we are looking for the specified case, checking /// that nothing we jump over contains labels. If Case is null, then we found /// the case and are looking for the break. /// /// If the recursive walk actually finds our Case, then we set FoundCase to /// true. /// enum CSFC_Result { CSFC_Failure, CSFC_FallThrough, CSFC_Success }; static CSFC_Result CollectStatementsForCase(const Stmt *S, const SwitchCase *Case, bool &FoundCase, SmallVectorImpl &ResultStmts) { // If this is a null statement, just succeed. if (!S) return Case ? CSFC_Success : CSFC_FallThrough; // If this is the switchcase (case 4: or default) that we're looking for, then // we're in business. Just add the substatement. if (const SwitchCase *SC = dyn_cast(S)) { if (S == Case) { FoundCase = true; return CollectStatementsForCase(SC->getSubStmt(), nullptr, FoundCase, ResultStmts); } // Otherwise, this is some other case or default statement, just ignore it. return CollectStatementsForCase(SC->getSubStmt(), Case, FoundCase, ResultStmts); } // If we are in the live part of the code and we found our break statement, // return a success! if (!Case && isa(S)) return CSFC_Success; // If this is a switch statement, then it might contain the SwitchCase, the // break, or neither. if (const CompoundStmt *CS = dyn_cast(S)) { // Handle this as two cases: we might be looking for the SwitchCase (if so // the skipped statements must be skippable) or we might already have it. CompoundStmt::const_body_iterator I = CS->body_begin(), E = CS->body_end(); bool StartedInLiveCode = FoundCase; unsigned StartSize = ResultStmts.size(); // If we've not found the case yet, scan through looking for it. if (Case) { // Keep track of whether we see a skipped declaration. The code could be // using the declaration even if it is skipped, so we can't optimize out // the decl if the kept statements might refer to it. bool HadSkippedDecl = false; // If we're looking for the case, just see if we can skip each of the // substatements. for (; Case && I != E; ++I) { HadSkippedDecl |= CodeGenFunction::mightAddDeclToScope(*I); switch (CollectStatementsForCase(*I, Case, FoundCase, ResultStmts)) { case CSFC_Failure: return CSFC_Failure; case CSFC_Success: // A successful result means that either 1) that the statement doesn't // have the case and is skippable, or 2) does contain the case value // and also contains the break to exit the switch. In the later case, // we just verify the rest of the statements are elidable. if (FoundCase) { // If we found the case and skipped declarations, we can't do the // optimization. if (HadSkippedDecl) return CSFC_Failure; for (++I; I != E; ++I) if (CodeGenFunction::ContainsLabel(*I, true)) return CSFC_Failure; return CSFC_Success; } break; case CSFC_FallThrough: // If we have a fallthrough condition, then we must have found the // case started to include statements. Consider the rest of the // statements in the compound statement as candidates for inclusion. assert(FoundCase && "Didn't find case but returned fallthrough?"); // We recursively found Case, so we're not looking for it anymore. Case = nullptr; // If we found the case and skipped declarations, we can't do the // optimization. if (HadSkippedDecl) return CSFC_Failure; break; } } if (!FoundCase) return CSFC_Success; assert(!HadSkippedDecl && "fallthrough after skipping decl"); } // If we have statements in our range, then we know that the statements are // live and need to be added to the set of statements we're tracking. bool AnyDecls = false; for (; I != E; ++I) { AnyDecls |= CodeGenFunction::mightAddDeclToScope(*I); switch (CollectStatementsForCase(*I, nullptr, FoundCase, ResultStmts)) { case CSFC_Failure: return CSFC_Failure; case CSFC_FallThrough: // A fallthrough result means that the statement was simple and just // included in ResultStmt, keep adding them afterwards. break; case CSFC_Success: // A successful result means that we found the break statement and // stopped statement inclusion. We just ensure that any leftover stmts // are skippable and return success ourselves. for (++I; I != E; ++I) if (CodeGenFunction::ContainsLabel(*I, true)) return CSFC_Failure; return CSFC_Success; } } // If we're about to fall out of a scope without hitting a 'break;', we // can't perform the optimization if there were any decls in that scope // (we'd lose their end-of-lifetime). if (AnyDecls) { // If the entire compound statement was live, there's one more thing we // can try before giving up: emit the whole thing as a single statement. // We can do that unless the statement contains a 'break;'. // FIXME: Such a break must be at the end of a construct within this one. // We could emit this by just ignoring the BreakStmts entirely. if (StartedInLiveCode && !CodeGenFunction::containsBreak(S)) { ResultStmts.resize(StartSize); ResultStmts.push_back(S); } else { return CSFC_Failure; } } return CSFC_FallThrough; } // Okay, this is some other statement that we don't handle explicitly, like a // for statement or increment etc. If we are skipping over this statement, // just verify it doesn't have labels, which would make it invalid to elide. if (Case) { if (CodeGenFunction::ContainsLabel(S, true)) return CSFC_Failure; return CSFC_Success; } // Otherwise, we want to include this statement. Everything is cool with that // so long as it doesn't contain a break out of the switch we're in. if (CodeGenFunction::containsBreak(S)) return CSFC_Failure; // Otherwise, everything is great. Include the statement and tell the caller // that we fall through and include the next statement as well. ResultStmts.push_back(S); return CSFC_FallThrough; } /// FindCaseStatementsForValue - Find the case statement being jumped to and /// then invoke CollectStatementsForCase to find the list of statements to emit /// for a switch on constant. See the comment above CollectStatementsForCase /// for more details. static bool FindCaseStatementsForValue(const SwitchStmt &S, const llvm::APSInt &ConstantCondValue, SmallVectorImpl &ResultStmts, ASTContext &C, const SwitchCase *&ResultCase) { // First step, find the switch case that is being branched to. We can do this // efficiently by scanning the SwitchCase list. const SwitchCase *Case = S.getSwitchCaseList(); const DefaultStmt *DefaultCase = nullptr; for (; Case; Case = Case->getNextSwitchCase()) { // It's either a default or case. Just remember the default statement in // case we're not jumping to any numbered cases. if (const DefaultStmt *DS = dyn_cast(Case)) { DefaultCase = DS; continue; } // Check to see if this case is the one we're looking for. const CaseStmt *CS = cast(Case); // Don't handle case ranges yet. if (CS->getRHS()) return false; // If we found our case, remember it as 'case'. if (CS->getLHS()->EvaluateKnownConstInt(C) == ConstantCondValue) break; } // If we didn't find a matching case, we use a default if it exists, or we // elide the whole switch body! if (!Case) { // It is safe to elide the body of the switch if it doesn't contain labels // etc. If it is safe, return successfully with an empty ResultStmts list. if (!DefaultCase) return !CodeGenFunction::ContainsLabel(&S); Case = DefaultCase; } // Ok, we know which case is being jumped to, try to collect all the // statements that follow it. This can fail for a variety of reasons. Also, // check to see that the recursive walk actually found our case statement. // Insane cases like this can fail to find it in the recursive walk since we // don't handle every stmt kind: // switch (4) { // while (1) { // case 4: ... bool FoundCase = false; ResultCase = Case; return CollectStatementsForCase(S.getBody(), Case, FoundCase, ResultStmts) != CSFC_Failure && FoundCase; } static Optional> getLikelihoodWeights(ArrayRef Likelihoods) { // Are there enough branches to weight them? if (Likelihoods.size() <= 1) return None; uint64_t NumUnlikely = 0; uint64_t NumNone = 0; uint64_t NumLikely = 0; for (const auto LH : Likelihoods) { switch (LH) { case Stmt::LH_Unlikely: ++NumUnlikely; break; case Stmt::LH_None: ++NumNone; break; case Stmt::LH_Likely: ++NumLikely; break; } } // Is there a likelihood attribute used? if (NumUnlikely == 0 && NumLikely == 0) return None; // When multiple cases share the same code they can be combined during // optimization. In that case the weights of the branch will be the sum of // the individual weights. Make sure the combined sum of all neutral cases // doesn't exceed the value of a single likely attribute. // The additions both avoid divisions by 0 and make sure the weights of None // don't exceed the weight of Likely. const uint64_t Likely = INT32_MAX / (NumLikely + 2); const uint64_t None = Likely / (NumNone + 1); const uint64_t Unlikely = 0; SmallVector Result; Result.reserve(Likelihoods.size()); for (const auto LH : Likelihoods) { switch (LH) { case Stmt::LH_Unlikely: Result.push_back(Unlikely); break; case Stmt::LH_None: Result.push_back(None); break; case Stmt::LH_Likely: Result.push_back(Likely); break; } } return Result; } void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) { // Handle nested switch statements. llvm::SwitchInst *SavedSwitchInsn = SwitchInsn; SmallVector *SavedSwitchWeights = SwitchWeights; SmallVector *SavedSwitchLikelihood = SwitchLikelihood; llvm::BasicBlock *SavedCRBlock = CaseRangeBlock; // See if we can constant fold the condition of the switch and therefore only // emit the live case statement (if any) of the switch. llvm::APSInt ConstantCondValue; if (ConstantFoldsToSimpleInteger(S.getCond(), ConstantCondValue)) { SmallVector CaseStmts; const SwitchCase *Case = nullptr; if (FindCaseStatementsForValue(S, ConstantCondValue, CaseStmts, getContext(), Case)) { if (Case) incrementProfileCounter(Case); RunCleanupsScope ExecutedScope(*this); if (S.getInit()) EmitStmt(S.getInit()); // Emit the condition variable if needed inside the entire cleanup scope // used by this special case for constant folded switches. if (S.getConditionVariable()) EmitDecl(*S.getConditionVariable()); // At this point, we are no longer "within" a switch instance, so // we can temporarily enforce this to ensure that any embedded case // statements are not emitted. SwitchInsn = nullptr; // Okay, we can dead code eliminate everything except this case. Emit the // specified series of statements and we're good. for (unsigned i = 0, e = CaseStmts.size(); i != e; ++i) EmitStmt(CaseStmts[i]); incrementProfileCounter(&S); // Now we want to restore the saved switch instance so that nested // switches continue to function properly SwitchInsn = SavedSwitchInsn; return; } } JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog"); RunCleanupsScope ConditionScope(*this); if (S.getInit()) EmitStmt(S.getInit()); if (S.getConditionVariable()) EmitDecl(*S.getConditionVariable()); llvm::Value *CondV = EmitScalarExpr(S.getCond()); // Create basic block to hold stuff that comes after switch // statement. We also need to create a default block now so that // explicit case ranges tests can have a place to jump to on // failure. llvm::BasicBlock *DefaultBlock = createBasicBlock("sw.default"); SwitchInsn = Builder.CreateSwitch(CondV, DefaultBlock); if (PGO.haveRegionCounts()) { // Walk the SwitchCase list to find how many there are. uint64_t DefaultCount = 0; unsigned NumCases = 0; for (const SwitchCase *Case = S.getSwitchCaseList(); Case; Case = Case->getNextSwitchCase()) { if (isa(Case)) DefaultCount = getProfileCount(Case); NumCases += 1; } SwitchWeights = new SmallVector(); SwitchWeights->reserve(NumCases); // The default needs to be first. We store the edge count, so we already // know the right weight. SwitchWeights->push_back(DefaultCount); } else if (CGM.getCodeGenOpts().OptimizationLevel) { SwitchLikelihood = new SmallVector(); // Initialize the default case. SwitchLikelihood->push_back(Stmt::LH_None); } CaseRangeBlock = DefaultBlock; // Clear the insertion point to indicate we are in unreachable code. Builder.ClearInsertionPoint(); // All break statements jump to NextBlock. If BreakContinueStack is non-empty // then reuse last ContinueBlock. JumpDest OuterContinue; if (!BreakContinueStack.empty()) OuterContinue = BreakContinueStack.back().ContinueBlock; BreakContinueStack.push_back(BreakContinue(SwitchExit, OuterContinue)); // Emit switch body. EmitStmt(S.getBody()); BreakContinueStack.pop_back(); // Update the default block in case explicit case range tests have // been chained on top. SwitchInsn->setDefaultDest(CaseRangeBlock); // If a default was never emitted: if (!DefaultBlock->getParent()) { // If we have cleanups, emit the default block so that there's a // place to jump through the cleanups from. if (ConditionScope.requiresCleanups()) { EmitBlock(DefaultBlock); // Otherwise, just forward the default block to the switch end. } else { DefaultBlock->replaceAllUsesWith(SwitchExit.getBlock()); delete DefaultBlock; } } ConditionScope.ForceCleanup(); // Emit continuation. EmitBlock(SwitchExit.getBlock(), true); incrementProfileCounter(&S); // If the switch has a condition wrapped by __builtin_unpredictable, // create metadata that specifies that the switch is unpredictable. // Don't bother if not optimizing because that metadata would not be used. auto *Call = dyn_cast(S.getCond()); if (Call && CGM.getCodeGenOpts().OptimizationLevel != 0) { auto *FD = dyn_cast_or_null(Call->getCalleeDecl()); if (FD && FD->getBuiltinID() == Builtin::BI__builtin_unpredictable) { llvm::MDBuilder MDHelper(getLLVMContext()); SwitchInsn->setMetadata(llvm::LLVMContext::MD_unpredictable, MDHelper.createUnpredictable()); } } if (SwitchWeights) { assert(SwitchWeights->size() == 1 + SwitchInsn->getNumCases() && "switch weights do not match switch cases"); // If there's only one jump destination there's no sense weighting it. if (SwitchWeights->size() > 1) SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof, createProfileWeights(*SwitchWeights)); delete SwitchWeights; } else if (SwitchLikelihood) { assert(SwitchLikelihood->size() == 1 + SwitchInsn->getNumCases() && "switch likelihoods do not match switch cases"); Optional> LHW = getLikelihoodWeights(*SwitchLikelihood); if (LHW) { llvm::MDBuilder MDHelper(CGM.getLLVMContext()); SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof, createProfileWeights(*LHW)); } delete SwitchLikelihood; } SwitchInsn = SavedSwitchInsn; SwitchWeights = SavedSwitchWeights; SwitchLikelihood = SavedSwitchLikelihood; CaseRangeBlock = SavedCRBlock; } static std::string SimplifyConstraint(const char *Constraint, const TargetInfo &Target, SmallVectorImpl *OutCons=nullptr) { std::string Result; while (*Constraint) { switch (*Constraint) { default: Result += Target.convertConstraint(Constraint); break; // Ignore these case '*': case '?': case '!': case '=': // Will see this and the following in mult-alt constraints. case '+': break; case '#': // Ignore the rest of the constraint alternative. while (Constraint[1] && Constraint[1] != ',') Constraint++; break; case '&': case '%': Result += *Constraint; while (Constraint[1] && Constraint[1] == *Constraint) Constraint++; break; case ',': Result += "|"; break; case 'g': Result += "imr"; break; case '[': { assert(OutCons && "Must pass output names to constraints with a symbolic name"); unsigned Index; bool result = Target.resolveSymbolicName(Constraint, *OutCons, Index); assert(result && "Could not resolve symbolic name"); (void)result; Result += llvm::utostr(Index); break; } } Constraint++; } return Result; } /// AddVariableConstraints - Look at AsmExpr and if it is a variable declared /// as using a particular register add that as a constraint that will be used /// in this asm stmt. static std::string AddVariableConstraints(const std::string &Constraint, const Expr &AsmExpr, const TargetInfo &Target, CodeGenModule &CGM, const AsmStmt &Stmt, const bool EarlyClobber, std::string *GCCReg = nullptr) { const DeclRefExpr *AsmDeclRef = dyn_cast(&AsmExpr); if (!AsmDeclRef) return Constraint; const ValueDecl &Value = *AsmDeclRef->getDecl(); const VarDecl *Variable = dyn_cast(&Value); if (!Variable) return Constraint; if (Variable->getStorageClass() != SC_Register) return Constraint; AsmLabelAttr *Attr = Variable->getAttr(); if (!Attr) return Constraint; StringRef Register = Attr->getLabel(); assert(Target.isValidGCCRegisterName(Register)); // We're using validateOutputConstraint here because we only care if // this is a register constraint. TargetInfo::ConstraintInfo Info(Constraint, ""); if (Target.validateOutputConstraint(Info) && !Info.allowsRegister()) { CGM.ErrorUnsupported(&Stmt, "__asm__"); return Constraint; } // Canonicalize the register here before returning it. Register = Target.getNormalizedGCCRegisterName(Register); if (GCCReg != nullptr) *GCCReg = Register.str(); return (EarlyClobber ? "&{" : "{") + Register.str() + "}"; } llvm::Value* CodeGenFunction::EmitAsmInputLValue(const TargetInfo::ConstraintInfo &Info, LValue InputValue, QualType InputType, std::string &ConstraintStr, SourceLocation Loc) { llvm::Value *Arg; if (Info.allowsRegister() || !Info.allowsMemory()) { if (CodeGenFunction::hasScalarEvaluationKind(InputType)) { Arg = EmitLoadOfLValue(InputValue, Loc).getScalarVal(); } else { llvm::Type *Ty = ConvertType(InputType); uint64_t Size = CGM.getDataLayout().getTypeSizeInBits(Ty); if (Size <= 64 && llvm::isPowerOf2_64(Size)) { Ty = llvm::IntegerType::get(getLLVMContext(), Size); Ty = llvm::PointerType::getUnqual(Ty); Arg = Builder.CreateLoad( Builder.CreateBitCast(InputValue.getAddress(*this), Ty)); } else { Arg = InputValue.getPointer(*this); ConstraintStr += '*'; } } } else { Arg = InputValue.getPointer(*this); ConstraintStr += '*'; } return Arg; } llvm::Value* CodeGenFunction::EmitAsmInput( const TargetInfo::ConstraintInfo &Info, const Expr *InputExpr, std::string &ConstraintStr) { // If this can't be a register or memory, i.e., has to be a constant // (immediate or symbolic), try to emit it as such. if (!Info.allowsRegister() && !Info.allowsMemory()) { if (Info.requiresImmediateConstant()) { Expr::EvalResult EVResult; InputExpr->EvaluateAsRValue(EVResult, getContext(), true); llvm::APSInt IntResult; if (EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(), getContext())) return llvm::ConstantInt::get(getLLVMContext(), IntResult); } Expr::EvalResult Result; if (InputExpr->EvaluateAsInt(Result, getContext())) return llvm::ConstantInt::get(getLLVMContext(), Result.Val.getInt()); } if (Info.allowsRegister() || !Info.allowsMemory()) if (CodeGenFunction::hasScalarEvaluationKind(InputExpr->getType())) return EmitScalarExpr(InputExpr); if (InputExpr->getStmtClass() == Expr::CXXThisExprClass) return EmitScalarExpr(InputExpr); InputExpr = InputExpr->IgnoreParenNoopCasts(getContext()); LValue Dest = EmitLValue(InputExpr); return EmitAsmInputLValue(Info, Dest, InputExpr->getType(), ConstraintStr, InputExpr->getExprLoc()); } /// getAsmSrcLocInfo - Return the !srcloc metadata node to attach to an inline /// asm call instruction. The !srcloc MDNode contains a list of constant /// integers which are the source locations of the start of each line in the /// asm. static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str, CodeGenFunction &CGF) { SmallVector Locs; // Add the location of the first line to the MDNode. Locs.push_back(llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( CGF.Int32Ty, Str->getBeginLoc().getRawEncoding()))); StringRef StrVal = Str->getString(); if (!StrVal.empty()) { const SourceManager &SM = CGF.CGM.getContext().getSourceManager(); const LangOptions &LangOpts = CGF.CGM.getLangOpts(); unsigned StartToken = 0; unsigned ByteOffset = 0; // Add the location of the start of each subsequent line of the asm to the // MDNode. for (unsigned i = 0, e = StrVal.size() - 1; i != e; ++i) { if (StrVal[i] != '\n') continue; SourceLocation LineLoc = Str->getLocationOfByte( i + 1, SM, LangOpts, CGF.getTarget(), &StartToken, &ByteOffset); Locs.push_back(llvm::ConstantAsMetadata::get( llvm::ConstantInt::get(CGF.Int32Ty, LineLoc.getRawEncoding()))); } } return llvm::MDNode::get(CGF.getLLVMContext(), Locs); } static void UpdateAsmCallInst(llvm::CallBase &Result, bool HasSideEffect, bool ReadOnly, bool ReadNone, bool NoMerge, const AsmStmt &S, const std::vector &ResultRegTypes, CodeGenFunction &CGF, std::vector &RegResults) { Result.addAttribute(llvm::AttributeList::FunctionIndex, llvm::Attribute::NoUnwind); if (NoMerge) Result.addAttribute(llvm::AttributeList::FunctionIndex, llvm::Attribute::NoMerge); // Attach readnone and readonly attributes. if (!HasSideEffect) { if (ReadNone) Result.addAttribute(llvm::AttributeList::FunctionIndex, llvm::Attribute::ReadNone); else if (ReadOnly) Result.addAttribute(llvm::AttributeList::FunctionIndex, llvm::Attribute::ReadOnly); } // Slap the source location of the inline asm into a !srcloc metadata on the // call. if (const auto *gccAsmStmt = dyn_cast(&S)) Result.setMetadata("srcloc", getAsmSrcLocInfo(gccAsmStmt->getAsmString(), CGF)); else { // At least put the line number on MS inline asm blobs. llvm::Constant *Loc = llvm::ConstantInt::get(CGF.Int32Ty, S.getAsmLoc().getRawEncoding()); Result.setMetadata("srcloc", llvm::MDNode::get(CGF.getLLVMContext(), llvm::ConstantAsMetadata::get(Loc))); } if (CGF.getLangOpts().assumeFunctionsAreConvergent()) // Conservatively, mark all inline asm blocks in CUDA or OpenCL as // convergent (meaning, they may call an intrinsically convergent op, such // as bar.sync, and so can't have certain optimizations applied around // them). Result.addAttribute(llvm::AttributeList::FunctionIndex, llvm::Attribute::Convergent); // Extract all of the register value results from the asm. if (ResultRegTypes.size() == 1) { RegResults.push_back(&Result); } else { for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) { llvm::Value *Tmp = CGF.Builder.CreateExtractValue(&Result, i, "asmresult"); RegResults.push_back(Tmp); } } } void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { // Assemble the final asm string. std::string AsmString = S.generateAsmString(getContext()); // Get all the output and input constraints together. SmallVector OutputConstraintInfos; SmallVector InputConstraintInfos; for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) { StringRef Name; if (const GCCAsmStmt *GAS = dyn_cast(&S)) Name = GAS->getOutputName(i); TargetInfo::ConstraintInfo Info(S.getOutputConstraint(i), Name); bool IsValid = getTarget().validateOutputConstraint(Info); (void)IsValid; assert(IsValid && "Failed to parse output constraint"); OutputConstraintInfos.push_back(Info); } for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) { StringRef Name; if (const GCCAsmStmt *GAS = dyn_cast(&S)) Name = GAS->getInputName(i); TargetInfo::ConstraintInfo Info(S.getInputConstraint(i), Name); bool IsValid = getTarget().validateInputConstraint(OutputConstraintInfos, Info); assert(IsValid && "Failed to parse input constraint"); (void)IsValid; InputConstraintInfos.push_back(Info); } std::string Constraints; std::vector ResultRegDests; std::vector ResultRegQualTys; std::vector ResultRegTypes; std::vector ResultTruncRegTypes; std::vector ArgTypes; std::vector Args; llvm::BitVector ResultTypeRequiresCast; // Keep track of inout constraints. std::string InOutConstraints; std::vector InOutArgs; std::vector InOutArgTypes; // Keep track of out constraints for tied input operand. std::vector OutputConstraints; // Keep track of defined physregs. llvm::SmallSet PhysRegOutputs; // An inline asm can be marked readonly if it meets the following conditions: // - it doesn't have any sideeffects // - it doesn't clobber memory // - it doesn't return a value by-reference // It can be marked readnone if it doesn't have any input memory constraints // in addition to meeting the conditions listed above. bool ReadOnly = true, ReadNone = true; for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) { TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i]; // Simplify the output constraint. std::string OutputConstraint(S.getOutputConstraint(i)); OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1, getTarget(), &OutputConstraintInfos); const Expr *OutExpr = S.getOutputExpr(i); OutExpr = OutExpr->IgnoreParenNoopCasts(getContext()); std::string GCCReg; OutputConstraint = AddVariableConstraints(OutputConstraint, *OutExpr, getTarget(), CGM, S, Info.earlyClobber(), &GCCReg); // Give an error on multiple outputs to same physreg. if (!GCCReg.empty() && !PhysRegOutputs.insert(GCCReg).second) CGM.Error(S.getAsmLoc(), "multiple outputs to hard register: " + GCCReg); OutputConstraints.push_back(OutputConstraint); LValue Dest = EmitLValue(OutExpr); if (!Constraints.empty()) Constraints += ','; // If this is a register output, then make the inline asm return it // by-value. If this is a memory result, return the value by-reference. bool isScalarizableAggregate = hasAggregateEvaluationKind(OutExpr->getType()); if (!Info.allowsMemory() && (hasScalarEvaluationKind(OutExpr->getType()) || isScalarizableAggregate)) { Constraints += "=" + OutputConstraint; ResultRegQualTys.push_back(OutExpr->getType()); ResultRegDests.push_back(Dest); ResultTruncRegTypes.push_back(ConvertTypeForMem(OutExpr->getType())); if (Info.allowsRegister() && isScalarizableAggregate) { ResultTypeRequiresCast.push_back(true); unsigned Size = getContext().getTypeSize(OutExpr->getType()); llvm::Type *ConvTy = llvm::IntegerType::get(getLLVMContext(), Size); ResultRegTypes.push_back(ConvTy); } else { ResultTypeRequiresCast.push_back(false); ResultRegTypes.push_back(ResultTruncRegTypes.back()); } // If this output is tied to an input, and if the input is larger, then // we need to set the actual result type of the inline asm node to be the // same as the input type. if (Info.hasMatchingInput()) { unsigned InputNo; for (InputNo = 0; InputNo != S.getNumInputs(); ++InputNo) { TargetInfo::ConstraintInfo &Input = InputConstraintInfos[InputNo]; if (Input.hasTiedOperand() && Input.getTiedOperand() == i) break; } assert(InputNo != S.getNumInputs() && "Didn't find matching input!"); QualType InputTy = S.getInputExpr(InputNo)->getType(); QualType OutputType = OutExpr->getType(); uint64_t InputSize = getContext().getTypeSize(InputTy); if (getContext().getTypeSize(OutputType) < InputSize) { // Form the asm to return the value as a larger integer or fp type. ResultRegTypes.back() = ConvertType(InputTy); } } if (llvm::Type* AdjTy = getTargetHooks().adjustInlineAsmType(*this, OutputConstraint, ResultRegTypes.back())) ResultRegTypes.back() = AdjTy; else { CGM.getDiags().Report(S.getAsmLoc(), diag::err_asm_invalid_type_in_input) << OutExpr->getType() << OutputConstraint; } // Update largest vector width for any vector types. if (auto *VT = dyn_cast(ResultRegTypes.back())) LargestVectorWidth = std::max((uint64_t)LargestVectorWidth, VT->getPrimitiveSizeInBits().getKnownMinSize()); } else { llvm::Type *DestAddrTy = Dest.getAddress(*this).getType(); llvm::Value *DestPtr = Dest.getPointer(*this); // Matrix types in memory are represented by arrays, but accessed through // vector pointers, with the alignment specified on the access operation. // For inline assembly, update pointer arguments to use vector pointers. // Otherwise there will be a mis-match if the matrix is also an // input-argument which is represented as vector. if (isa(OutExpr->getType().getCanonicalType())) { DestAddrTy = llvm::PointerType::get( ConvertType(OutExpr->getType()), cast(DestAddrTy)->getAddressSpace()); DestPtr = Builder.CreateBitCast(DestPtr, DestAddrTy); } ArgTypes.push_back(DestAddrTy); Args.push_back(DestPtr); Constraints += "=*"; Constraints += OutputConstraint; ReadOnly = ReadNone = false; } if (Info.isReadWrite()) { InOutConstraints += ','; const Expr *InputExpr = S.getOutputExpr(i); llvm::Value *Arg = EmitAsmInputLValue(Info, Dest, InputExpr->getType(), InOutConstraints, InputExpr->getExprLoc()); if (llvm::Type* AdjTy = getTargetHooks().adjustInlineAsmType(*this, OutputConstraint, Arg->getType())) Arg = Builder.CreateBitCast(Arg, AdjTy); // Update largest vector width for any vector types. if (auto *VT = dyn_cast(Arg->getType())) LargestVectorWidth = std::max((uint64_t)LargestVectorWidth, VT->getPrimitiveSizeInBits().getKnownMinSize()); // Only tie earlyclobber physregs. if (Info.allowsRegister() && (GCCReg.empty() || Info.earlyClobber())) InOutConstraints += llvm::utostr(i); else InOutConstraints += OutputConstraint; InOutArgTypes.push_back(Arg->getType()); InOutArgs.push_back(Arg); } } // If this is a Microsoft-style asm blob, store the return registers (EAX:EDX) // to the return value slot. Only do this when returning in registers. if (isa(&S)) { const ABIArgInfo &RetAI = CurFnInfo->getReturnInfo(); if (RetAI.isDirect() || RetAI.isExtend()) { // Make a fake lvalue for the return value slot. LValue ReturnSlot = MakeAddrLValue(ReturnValue, FnRetTy); CGM.getTargetCodeGenInfo().addReturnRegisterOutputs( *this, ReturnSlot, Constraints, ResultRegTypes, ResultTruncRegTypes, ResultRegDests, AsmString, S.getNumOutputs()); SawAsmBlock = true; } } for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) { const Expr *InputExpr = S.getInputExpr(i); TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; if (Info.allowsMemory()) ReadNone = false; if (!Constraints.empty()) Constraints += ','; // Simplify the input constraint. std::string InputConstraint(S.getInputConstraint(i)); InputConstraint = SimplifyConstraint(InputConstraint.c_str(), getTarget(), &OutputConstraintInfos); InputConstraint = AddVariableConstraints( InputConstraint, *InputExpr->IgnoreParenNoopCasts(getContext()), getTarget(), CGM, S, false /* No EarlyClobber */); std::string ReplaceConstraint (InputConstraint); llvm::Value *Arg = EmitAsmInput(Info, InputExpr, Constraints); // If this input argument is tied to a larger output result, extend the // input to be the same size as the output. The LLVM backend wants to see // the input and output of a matching constraint be the same size. Note // that GCC does not define what the top bits are here. We use zext because // that is usually cheaper, but LLVM IR should really get an anyext someday. if (Info.hasTiedOperand()) { unsigned Output = Info.getTiedOperand(); QualType OutputType = S.getOutputExpr(Output)->getType(); QualType InputTy = InputExpr->getType(); if (getContext().getTypeSize(OutputType) > getContext().getTypeSize(InputTy)) { // Use ptrtoint as appropriate so that we can do our extension. if (isa(Arg->getType())) Arg = Builder.CreatePtrToInt(Arg, IntPtrTy); llvm::Type *OutputTy = ConvertType(OutputType); if (isa(OutputTy)) Arg = Builder.CreateZExt(Arg, OutputTy); else if (isa(OutputTy)) Arg = Builder.CreateZExt(Arg, IntPtrTy); else { assert(OutputTy->isFloatingPointTy() && "Unexpected output type"); Arg = Builder.CreateFPExt(Arg, OutputTy); } } // Deal with the tied operands' constraint code in adjustInlineAsmType. ReplaceConstraint = OutputConstraints[Output]; } if (llvm::Type* AdjTy = getTargetHooks().adjustInlineAsmType(*this, ReplaceConstraint, Arg->getType())) Arg = Builder.CreateBitCast(Arg, AdjTy); else CGM.getDiags().Report(S.getAsmLoc(), diag::err_asm_invalid_type_in_input) << InputExpr->getType() << InputConstraint; // Update largest vector width for any vector types. if (auto *VT = dyn_cast(Arg->getType())) LargestVectorWidth = std::max((uint64_t)LargestVectorWidth, VT->getPrimitiveSizeInBits().getKnownMinSize()); ArgTypes.push_back(Arg->getType()); Args.push_back(Arg); Constraints += InputConstraint; } // Labels SmallVector Transfer; llvm::BasicBlock *Fallthrough = nullptr; bool IsGCCAsmGoto = false; if (const auto *GS = dyn_cast(&S)) { IsGCCAsmGoto = GS->isAsmGoto(); if (IsGCCAsmGoto) { for (const auto *E : GS->labels()) { JumpDest Dest = getJumpDestForLabel(E->getLabel()); Transfer.push_back(Dest.getBlock()); llvm::BlockAddress *BA = llvm::BlockAddress::get(CurFn, Dest.getBlock()); Args.push_back(BA); ArgTypes.push_back(BA->getType()); if (!Constraints.empty()) Constraints += ','; Constraints += 'X'; } Fallthrough = createBasicBlock("asm.fallthrough"); } } // Append the "input" part of inout constraints last. for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) { ArgTypes.push_back(InOutArgTypes[i]); Args.push_back(InOutArgs[i]); } Constraints += InOutConstraints; // Clobbers for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) { StringRef Clobber = S.getClobber(i); if (Clobber == "memory") ReadOnly = ReadNone = false; else if (Clobber != "cc") { Clobber = getTarget().getNormalizedGCCRegisterName(Clobber); if (CGM.getCodeGenOpts().StackClashProtector && getTarget().isSPRegName(Clobber)) { CGM.getDiags().Report(S.getAsmLoc(), diag::warn_stack_clash_protection_inline_asm); } } if (!Constraints.empty()) Constraints += ','; Constraints += "~{"; Constraints += Clobber; Constraints += '}'; } // Add machine specific clobbers std::string MachineClobbers = getTarget().getClobbers(); if (!MachineClobbers.empty()) { if (!Constraints.empty()) Constraints += ','; Constraints += MachineClobbers; } llvm::Type *ResultType; if (ResultRegTypes.empty()) ResultType = VoidTy; else if (ResultRegTypes.size() == 1) ResultType = ResultRegTypes[0]; else ResultType = llvm::StructType::get(getLLVMContext(), ResultRegTypes); llvm::FunctionType *FTy = llvm::FunctionType::get(ResultType, ArgTypes, false); bool HasSideEffect = S.isVolatile() || S.getNumOutputs() == 0; llvm::InlineAsm::AsmDialect AsmDialect = isa(&S) ? llvm::InlineAsm::AD_Intel : llvm::InlineAsm::AD_ATT; llvm::InlineAsm *IA = llvm::InlineAsm::get(FTy, AsmString, Constraints, HasSideEffect, /* IsAlignStack */ false, AsmDialect); std::vector RegResults; if (IsGCCAsmGoto) { llvm::CallBrInst *Result = Builder.CreateCallBr(IA, Fallthrough, Transfer, Args); EmitBlock(Fallthrough); UpdateAsmCallInst(cast(*Result), HasSideEffect, ReadOnly, ReadNone, InNoMergeAttributedStmt, S, ResultRegTypes, *this, RegResults); } else { llvm::CallInst *Result = Builder.CreateCall(IA, Args, getBundlesForFunclet(IA)); UpdateAsmCallInst(cast(*Result), HasSideEffect, ReadOnly, ReadNone, InNoMergeAttributedStmt, S, ResultRegTypes, *this, RegResults); } assert(RegResults.size() == ResultRegTypes.size()); assert(RegResults.size() == ResultTruncRegTypes.size()); assert(RegResults.size() == ResultRegDests.size()); // ResultRegDests can be also populated by addReturnRegisterOutputs() above, // in which case its size may grow. assert(ResultTypeRequiresCast.size() <= ResultRegDests.size()); for (unsigned i = 0, e = RegResults.size(); i != e; ++i) { llvm::Value *Tmp = RegResults[i]; // If the result type of the LLVM IR asm doesn't match the result type of // the expression, do the conversion. if (ResultRegTypes[i] != ResultTruncRegTypes[i]) { llvm::Type *TruncTy = ResultTruncRegTypes[i]; // Truncate the integer result to the right size, note that TruncTy can be // a pointer. if (TruncTy->isFloatingPointTy()) Tmp = Builder.CreateFPTrunc(Tmp, TruncTy); else if (TruncTy->isPointerTy() && Tmp->getType()->isIntegerTy()) { uint64_t ResSize = CGM.getDataLayout().getTypeSizeInBits(TruncTy); Tmp = Builder.CreateTrunc(Tmp, llvm::IntegerType::get(getLLVMContext(), (unsigned)ResSize)); Tmp = Builder.CreateIntToPtr(Tmp, TruncTy); } else if (Tmp->getType()->isPointerTy() && TruncTy->isIntegerTy()) { uint64_t TmpSize =CGM.getDataLayout().getTypeSizeInBits(Tmp->getType()); Tmp = Builder.CreatePtrToInt(Tmp, llvm::IntegerType::get(getLLVMContext(), (unsigned)TmpSize)); Tmp = Builder.CreateTrunc(Tmp, TruncTy); } else if (TruncTy->isIntegerTy()) { Tmp = Builder.CreateZExtOrTrunc(Tmp, TruncTy); } else if (TruncTy->isVectorTy()) { Tmp = Builder.CreateBitCast(Tmp, TruncTy); } } LValue Dest = ResultRegDests[i]; // ResultTypeRequiresCast elements correspond to the first // ResultTypeRequiresCast.size() elements of RegResults. if ((i < ResultTypeRequiresCast.size()) && ResultTypeRequiresCast[i]) { unsigned Size = getContext().getTypeSize(ResultRegQualTys[i]); Address A = Builder.CreateBitCast(Dest.getAddress(*this), ResultRegTypes[i]->getPointerTo()); QualType Ty = getContext().getIntTypeForBitwidth(Size, /*Signed*/ false); if (Ty.isNull()) { const Expr *OutExpr = S.getOutputExpr(i); CGM.Error( OutExpr->getExprLoc(), "impossible constraint in asm: can't store value into a register"); return; } Dest = MakeAddrLValue(A, Ty); } EmitStoreThroughLValue(RValue::get(Tmp), Dest); } } LValue CodeGenFunction::InitCapturedStruct(const CapturedStmt &S) { const RecordDecl *RD = S.getCapturedRecordDecl(); QualType RecordTy = getContext().getRecordType(RD); // Initialize the captured struct. LValue SlotLV = MakeAddrLValue(CreateMemTemp(RecordTy, "agg.captured"), RecordTy); RecordDecl::field_iterator CurField = RD->field_begin(); for (CapturedStmt::const_capture_init_iterator I = S.capture_init_begin(), E = S.capture_init_end(); I != E; ++I, ++CurField) { LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField); if (CurField->hasCapturedVLAType()) { EmitLambdaVLACapture(CurField->getCapturedVLAType(), LV); } else { EmitInitializerForField(*CurField, LV, *I); } } return SlotLV; } /// Generate an outlined function for the body of a CapturedStmt, store any /// captured variables into the captured struct, and call the outlined function. llvm::Function * CodeGenFunction::EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K) { LValue CapStruct = InitCapturedStruct(S); // Emit the CapturedDecl CodeGenFunction CGF(CGM, true); CGCapturedStmtRAII CapInfoRAII(CGF, new CGCapturedStmtInfo(S, K)); llvm::Function *F = CGF.GenerateCapturedStmtFunction(S); delete CGF.CapturedStmtInfo; // Emit call to the helper function. EmitCallOrInvoke(F, CapStruct.getPointer(*this)); return F; } Address CodeGenFunction::GenerateCapturedStmtArgument(const CapturedStmt &S) { LValue CapStruct = InitCapturedStruct(S); return CapStruct.getAddress(*this); } /// Creates the outlined function for a CapturedStmt. llvm::Function * CodeGenFunction::GenerateCapturedStmtFunction(const CapturedStmt &S) { assert(CapturedStmtInfo && "CapturedStmtInfo should be set when generating the captured function"); const CapturedDecl *CD = S.getCapturedDecl(); const RecordDecl *RD = S.getCapturedRecordDecl(); SourceLocation Loc = S.getBeginLoc(); assert(CD->hasBody() && "missing CapturedDecl body"); // Build the argument list. ASTContext &Ctx = CGM.getContext(); FunctionArgList Args; Args.append(CD->param_begin(), CD->param_end()); // Create the function declaration. const CGFunctionInfo &FuncInfo = CGM.getTypes().arrangeBuiltinFunctionDeclaration(Ctx.VoidTy, Args); llvm::FunctionType *FuncLLVMTy = CGM.getTypes().GetFunctionType(FuncInfo); llvm::Function *F = llvm::Function::Create(FuncLLVMTy, llvm::GlobalValue::InternalLinkage, CapturedStmtInfo->getHelperName(), &CGM.getModule()); CGM.SetInternalFunctionAttributes(CD, F, FuncInfo); if (CD->isNothrow()) F->addFnAttr(llvm::Attribute::NoUnwind); // Generate the function. StartFunction(CD, Ctx.VoidTy, F, FuncInfo, Args, CD->getLocation(), CD->getBody()->getBeginLoc()); // Set the context parameter in CapturedStmtInfo. Address DeclPtr = GetAddrOfLocalVar(CD->getContextParam()); CapturedStmtInfo->setContextValue(Builder.CreateLoad(DeclPtr)); // Initialize variable-length arrays. LValue Base = MakeNaturalAlignAddrLValue(CapturedStmtInfo->getContextValue(), Ctx.getTagDeclType(RD)); for (auto *FD : RD->fields()) { if (FD->hasCapturedVLAType()) { auto *ExprArg = EmitLoadOfLValue(EmitLValueForField(Base, FD), S.getBeginLoc()) .getScalarVal(); auto VAT = FD->getCapturedVLAType(); VLASizeMap[VAT->getSizeExpr()] = ExprArg; } } // If 'this' is captured, load it into CXXThisValue. if (CapturedStmtInfo->isCXXThisExprCaptured()) { FieldDecl *FD = CapturedStmtInfo->getThisFieldDecl(); LValue ThisLValue = EmitLValueForField(Base, FD); CXXThisValue = EmitLoadOfLValue(ThisLValue, Loc).getScalarVal(); } PGO.assignRegionCounters(GlobalDecl(CD), F); CapturedStmtInfo->EmitBody(*this, CD->getBody()); FinishFunction(CD->getBodyRBrace()); return F; }