1 //===- MCObjectStreamer.h - MCStreamer Object File Interface ----*- 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 #ifndef LLVM_MC_MCOBJECTSTREAMER_H
11 #define LLVM_MC_MCOBJECTSTREAMER_H
13 #include "llvm/ADT/SmallVector.h"
14 #include "llvm/MC/MCAssembler.h"
15 #include "llvm/MC/MCSection.h"
16 #include "llvm/MC/MCStreamer.h"
21 class MCSubtargetInfo;
27 class raw_pwrite_stream;
29 /// Streaming object file generation interface.
31 /// This class provides an implementation of the MCStreamer interface which is
32 /// suitable for use with the assembler backend. Specific object file formats
33 /// are expected to subclass this interface to implement directives specific
34 /// to that file format or custom semantics expected by the object writer
36 class MCObjectStreamer : public MCStreamer {
37 std::unique_ptr<MCAssembler> Assembler;
38 MCSection::iterator CurInsertionPoint;
41 SmallVector<MCSymbol *, 2> PendingLabels;
42 struct PendingMCFixup {
46 PendingMCFixup(const MCSymbol *McSym, MCDataFragment *F, MCFixup McFixup)
47 : Sym(McSym), Fixup(McFixup), DF(F) {}
49 SmallVector<PendingMCFixup, 2> PendingFixups;
51 virtual void EmitInstToData(const MCInst &Inst, const MCSubtargetInfo&) = 0;
52 void EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) override;
53 void EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) override;
54 MCSymbol *EmitCFILabel() override;
55 void EmitInstructionImpl(const MCInst &Inst, const MCSubtargetInfo &STI);
56 void resolvePendingFixups();
59 MCObjectStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
60 std::unique_ptr<MCObjectWriter> OW,
61 std::unique_ptr<MCCodeEmitter> Emitter);
66 void reset() override;
68 /// Object streamers require the integrated assembler.
69 bool isIntegratedAssemblerRequired() const override { return true; }
71 void EmitFrames(MCAsmBackend *MAB);
72 void EmitCFISections(bool EH, bool Debug) override;
74 MCFragment *getCurrentFragment() const;
76 void insert(MCFragment *F) {
77 flushPendingLabels(F);
78 MCSection *CurSection = getCurrentSectionOnly();
79 CurSection->getFragmentList().insert(CurInsertionPoint, F);
80 F->setParent(CurSection);
83 /// Get a data fragment to write into, creating a new one if the current
84 /// fragment is not a data fragment.
85 /// Optionally a \p STI can be passed in so that a new fragment is created
86 /// if the Subtarget differs from the current fragment.
87 MCDataFragment *getOrCreateDataFragment(const MCSubtargetInfo* STI = nullptr);
88 MCPaddingFragment *getOrCreatePaddingFragment();
91 bool changeSectionImpl(MCSection *Section, const MCExpr *Subsection);
93 /// If any labels have been emitted but not assigned fragments, ensure that
94 /// they get assigned, either to F if possible or to a new data fragment.
95 /// Optionally, it is also possible to provide an offset \p FOffset, which
96 /// will be used as a symbol offset within the fragment.
97 void flushPendingLabels(MCFragment *F, uint64_t FOffset = 0);
100 void visitUsedSymbol(const MCSymbol &Sym) override;
102 /// Create a dummy fragment to assign any pending labels.
103 void flushPendingLabels() { flushPendingLabels(nullptr); }
105 MCAssembler &getAssembler() { return *Assembler; }
106 MCAssembler *getAssemblerPtr() override;
107 /// \name MCStreamer Interface
110 void EmitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc()) override;
111 virtual void EmitLabel(MCSymbol *Symbol, SMLoc Loc, MCFragment *F);
112 void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) override;
113 void EmitValueImpl(const MCExpr *Value, unsigned Size,
114 SMLoc Loc = SMLoc()) override;
115 void EmitULEB128Value(const MCExpr *Value) override;
116 void EmitSLEB128Value(const MCExpr *Value) override;
117 void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) override;
118 void ChangeSection(MCSection *Section, const MCExpr *Subsection) override;
119 void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
120 bool = false) override;
122 /// Emit an instruction to a special fragment, because this instruction
123 /// can change its size during relaxation.
124 virtual void EmitInstToFragment(const MCInst &Inst, const MCSubtargetInfo &);
126 void EmitBundleAlignMode(unsigned AlignPow2) override;
127 void EmitBundleLock(bool AlignToEnd) override;
128 void EmitBundleUnlock() override;
129 void EmitBytes(StringRef Data) override;
130 void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
131 unsigned ValueSize = 1,
132 unsigned MaxBytesToEmit = 0) override;
133 void EmitCodeAlignment(unsigned ByteAlignment,
134 unsigned MaxBytesToEmit = 0) override;
135 void emitValueToOffset(const MCExpr *Offset, unsigned char Value,
138 EmitCodePaddingBasicBlockStart(const MCCodePaddingContext &Context) override;
140 EmitCodePaddingBasicBlockEnd(const MCCodePaddingContext &Context) override;
141 void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
142 unsigned Column, unsigned Flags,
143 unsigned Isa, unsigned Discriminator,
144 StringRef FileName) override;
145 void EmitDwarfAdvanceLineAddr(int64_t LineDelta, const MCSymbol *LastLabel,
146 const MCSymbol *Label,
147 unsigned PointerSize);
148 void EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
149 const MCSymbol *Label);
150 void EmitCVLocDirective(unsigned FunctionId, unsigned FileNo, unsigned Line,
151 unsigned Column, bool PrologueEnd, bool IsStmt,
152 StringRef FileName, SMLoc Loc) override;
153 void EmitCVLinetableDirective(unsigned FunctionId, const MCSymbol *Begin,
154 const MCSymbol *End) override;
155 void EmitCVInlineLinetableDirective(unsigned PrimaryFunctionId,
156 unsigned SourceFileId,
157 unsigned SourceLineNum,
158 const MCSymbol *FnStartSym,
159 const MCSymbol *FnEndSym) override;
160 void EmitCVDefRangeDirective(
161 ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
162 StringRef FixedSizePortion) override;
163 void EmitCVStringTableDirective() override;
164 void EmitCVFileChecksumsDirective() override;
165 void EmitCVFileChecksumOffsetDirective(unsigned FileNo) override;
166 void EmitDTPRel32Value(const MCExpr *Value) override;
167 void EmitDTPRel64Value(const MCExpr *Value) override;
168 void EmitTPRel32Value(const MCExpr *Value) override;
169 void EmitTPRel64Value(const MCExpr *Value) override;
170 void EmitGPRel32Value(const MCExpr *Value) override;
171 void EmitGPRel64Value(const MCExpr *Value) override;
172 bool EmitRelocDirective(const MCExpr &Offset, StringRef Name,
173 const MCExpr *Expr, SMLoc Loc,
174 const MCSubtargetInfo &STI) override;
175 using MCStreamer::emitFill;
176 void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
177 SMLoc Loc = SMLoc()) override;
178 void emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
179 SMLoc Loc = SMLoc()) override;
180 void EmitFileDirective(StringRef Filename) override;
182 void EmitAddrsig() override;
183 void EmitAddrsigSym(const MCSymbol *Sym) override;
185 void FinishImpl() override;
187 /// Emit the absolute difference between two symbols if possible.
189 /// Emit the absolute difference between \c Hi and \c Lo, as long as we can
190 /// compute it. Currently, that requires that both symbols are in the same
191 /// data fragment and that the target has not specified that diff expressions
192 /// require relocations to be emitted. Otherwise, do nothing and return
195 /// \pre Offset of \c Hi is greater than the offset \c Lo.
196 void emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo,
197 unsigned Size) override;
199 void emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi,
200 const MCSymbol *Lo) override;
202 bool mayHaveInstructions(MCSection &Sec) const override;
205 } // end namespace llvm