1 //===-- llvm/CodeGen/DebugHandlerBase.h -----------------------*- C++ -*--===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Common functionality for different debug information format backends.
11 // LLVM currently supports DWARF and CodeView.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CODEGEN_DEBUGHANDLERBASE_H
16 #define LLVM_CODEGEN_DEBUGHANDLERBASE_H
18 #include "llvm/ADT/Optional.h"
19 #include "llvm/CodeGen/AsmPrinterHandler.h"
20 #include "llvm/CodeGen/DbgEntityHistoryCalculator.h"
21 #include "llvm/CodeGen/LexicalScopes.h"
22 #include "llvm/CodeGen/MachineInstr.h"
23 #include "llvm/IR/DebugInfoMetadata.h"
29 class MachineModuleInfo;
31 /// Represents the location at which a variable is stored.
32 struct DbgVariableLocation {
36 /// Chain of offsetted loads necessary to load the value if it lives in
37 /// memory. Every load except for the last is pointer-sized.
38 SmallVector<int64_t, 1> LoadChain;
40 /// Present if the location is part of a larger variable.
41 llvm::Optional<llvm::DIExpression::FragmentInfo> FragmentInfo;
43 /// Extract a VariableLocation from a MachineInstr.
44 /// This will only work if Instruction is a debug value instruction
45 /// and the associated DIExpression is in one of the supported forms.
46 /// If these requirements are not met, the returned Optional will not
48 static Optional<DbgVariableLocation>
49 extractFromMachineInstruction(const MachineInstr &Instruction);
52 /// Base class for debug information backends. Common functionality related to
53 /// tracking which variables and scopes are alive at a given PC live here.
54 class DebugHandlerBase : public AsmPrinterHandler {
56 DebugHandlerBase(AsmPrinter *A);
58 /// Target of debug info emission.
61 /// Collected machine module information.
62 MachineModuleInfo *MMI;
64 /// Previous instruction's location information. This is used to
65 /// determine label location to indicate scope boundaries in debug info.
66 /// We track the previous instruction's source location (if not line 0),
67 /// whether it was a label, and its parent BB.
69 MCSymbol *PrevLabel = nullptr;
70 const MachineBasicBlock *PrevInstBB = nullptr;
72 /// This location indicates end of function prologue and beginning of
74 DebugLoc PrologEndLoc;
76 /// If nonnull, stores the current machine instruction we're processing.
77 const MachineInstr *CurMI = nullptr;
79 LexicalScopes LScopes;
81 /// History of DBG_VALUE and clobber instructions for each user
82 /// variable. Variables are listed in order of appearance.
83 DbgValueHistoryMap DbgValues;
85 /// Mapping of inlined labels and DBG_LABEL machine instruction.
86 DbgLabelInstrMap DbgLabels;
88 /// Maps instruction with label emitted before instruction.
89 /// FIXME: Make this private from DwarfDebug, we have the necessary accessors
91 DenseMap<const MachineInstr *, MCSymbol *> LabelsBeforeInsn;
93 /// Maps instruction with label emitted after instruction.
94 DenseMap<const MachineInstr *, MCSymbol *> LabelsAfterInsn;
96 /// Indentify instructions that are marking the beginning of or
97 /// ending of a scope.
98 void identifyScopeMarkers();
100 /// Ensure that a label will be emitted before MI.
101 void requestLabelBeforeInsn(const MachineInstr *MI) {
102 LabelsBeforeInsn.insert(std::make_pair(MI, nullptr));
105 /// Ensure that a label will be emitted after MI.
106 void requestLabelAfterInsn(const MachineInstr *MI) {
107 LabelsAfterInsn.insert(std::make_pair(MI, nullptr));
110 virtual void beginFunctionImpl(const MachineFunction *MF) = 0;
111 virtual void endFunctionImpl(const MachineFunction *MF) = 0;
112 virtual void skippedNonDebugFunction() {}
114 // AsmPrinterHandler overrides.
116 void beginInstruction(const MachineInstr *MI) override;
117 void endInstruction() override;
119 void beginFunction(const MachineFunction *MF) override;
120 void endFunction(const MachineFunction *MF) override;
122 /// Return Label preceding the instruction.
123 MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
125 /// Return Label immediately following the instruction.
126 MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
128 /// Return the function-local offset of an instruction. A label for the
129 /// instruction \p MI should exist (\ref getLabelAfterInsn).
130 const MCExpr *getFunctionLocalOffsetAfterInsn(const MachineInstr *MI);
132 /// If this type is derived from a base type then return base type size.
133 static uint64_t getBaseTypeSize(const DITypeRef TyRef);