//===- MCStreamer.h - High-level Streaming Machine Code Output --*- C++ -*-===//
//
// 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 file declares the MCStreamer class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCSTREAMER_H
#define LLVM_MC_MCSTREAMER_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCLinkerOptimizationHint.h"
#include "llvm/MC/MCPseudoProbe.h"
#include "llvm/MC/MCWinEH.h"
#include "llvm/Support/ARMTargetParser.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/MD5.h"
#include "llvm/Support/SMLoc.h"
#include "llvm/Support/VersionTuple.h"
#include <cassert>
#include <cstdint>
#include <memory>
#include <optional>
#include <string>
#include <utility>
#include <vector>
namespace llvm {
class APInt;
class AssemblerConstantPools;
class MCAsmBackend;
class MCAssembler;
class MCContext;
class MCExpr;
class MCFragment;
class MCInst;
class MCInstPrinter;
class MCRegister;
class MCSection;
class MCStreamer;
class MCSubtargetInfo;
class MCSymbol;
class MCSymbolRefExpr;
class Triple;
class Twine;
class raw_ostream;
namespace codeview {
struct DefRangeRegisterRelHeader;
struct DefRangeSubfieldRegisterHeader;
struct DefRangeRegisterHeader;
struct DefRangeFramePointerRelHeader;
}
using MCSectionSubPair = std::pair<MCSection *, const MCExpr *>;
/// Target specific streamer interface. This is used so that targets can
/// implement support for target specific assembly directives.
///
/// If target foo wants to use this, it should implement 3 classes:
/// * FooTargetStreamer : public MCTargetStreamer
/// * FooTargetAsmStreamer : public FooTargetStreamer
/// * FooTargetELFStreamer : public FooTargetStreamer
///
/// FooTargetStreamer should have a pure virtual method for each directive. For
/// example, for a ".bar symbol_name" directive, it should have
/// virtual emitBar(const MCSymbol &Symbol) = 0;
///
/// The FooTargetAsmStreamer and FooTargetELFStreamer classes implement the
/// method. The assembly streamer just prints ".bar symbol_name". The object
/// streamer does whatever is needed to implement .bar in the object file.
///
/// In the assembly printer and parser the target streamer can be used by
/// calling getTargetStreamer and casting it to FooTargetStreamer:
///
/// MCTargetStreamer &TS = OutStreamer.getTargetStreamer();
/// FooTargetStreamer &ATS = static_cast<FooTargetStreamer &>(TS);
///
/// The base classes FooTargetAsmStreamer and FooTargetELFStreamer should
/// *never* be treated differently. Callers should always talk to a
/// FooTargetStreamer.
class MCTargetStreamer {
protected:
MCStreamer &Streamer;
public:
MCTargetStreamer(MCStreamer &S);
virtual ~MCTargetStreamer();
MCStreamer &getStreamer() { return Streamer; }
// Allow a target to add behavior to the EmitLabel of MCStreamer.
virtual void emitLabel(MCSymbol *Symbol);
// Allow a target to add behavior to the emitAssignment of MCStreamer.
virtual void emitAssignment(MCSymbol *Symbol, const MCExpr *Value);
virtual void prettyPrintAsm(MCInstPrinter &InstPrinter, uint64_t Address,
const MCInst &Inst, const MCSubtargetInfo &STI,
raw_ostream &OS);
virtual void emitDwarfFileDirective(StringRef Directive);
/// Update streamer for a new active section.
///
/// This is called by popSection and switchSection, if the current
/// section changes.
virtual void changeSection(const MCSection *CurSection, MCSection *Section,
const MCExpr *SubSection, raw_ostream &OS);
virtual void emitValue(const MCExpr *Value);
/// Emit the bytes in \p Data into the output.
///
/// This is used to emit bytes in \p Data as sequence of .byte directives.
virtual void emitRawBytes(StringRef Data);
virtual void emitConstantPools();
virtual void finish();
};
// FIXME: declared here because it is used from
// lib/CodeGen/AsmPrinter/ARMException.cpp.
class ARMTargetStreamer : public MCTargetStreamer {
public:
ARMTargetStreamer(MCStreamer &S);
~ARMTargetStreamer() override;
virtual void emitFnStart();
virtual void emitFnEnd();
virtual void emitCantUnwind();
virtual void emitPersonality(const MCSymbol *Personality);
virtual void emitPersonalityIndex(unsigned Index);
virtual void emitHandlerData();
virtual void emitSetFP(unsigned FpReg, unsigned SpReg,
int64_t Offset = 0);
virtual void emitMovSP(unsigned Reg, int64_t Offset = 0);
virtual void emitPad(int64_t Offset);
virtual void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
bool isVector);
virtual void emitUnwindRaw(int64_t StackOffset,
const SmallVectorImpl<uint8_t> &Opcodes);
virtual void switchVendor(StringRef Vendor);
virtual void emitAttribute(unsigned Attribute, unsigned Value);
virtual void emitTextAttribute(unsigned Attribute, StringRef String);
virtual void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
StringRef StringValue = "");
virtual void emitFPU(unsigned FPU);
virtual void emitArch(ARM::ArchKind Arch);
virtual void emitArchExtension(uint64_t ArchExt);
virtual void emitObjectArch(ARM::ArchKind Arch);
void emitTargetAttributes(const MCSubtargetInfo &STI);
virtual void finishAttributeSection();
virtual void emitInst(uint32_t Inst, char Suffix = '\0');
virtual void annotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE);
virtual void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value);
void emitConstantPools() override;
virtual void emitARMWinCFIAllocStack(unsigned Size, bool Wide);
virtual void emitARMWinCFISaveRegMask(unsigned Mask, bool Wide);
virtual void emitARMWinCFISaveSP(unsigned Reg);
virtual void emitARMWinCFISaveFRegs(unsigned First, unsigned Last);
virtual void emitARMWinCFISaveLR(unsigned Offset);
virtual void emitARMWinCFIPrologEnd(bool Fragment);
virtual void emitARMWinCFINop(bool Wide);
virtual void emitARMWinCFIEpilogStart(unsigned Condition);
virtual void emitARMWinCFIEpilogEnd();
virtual void emitARMWinCFICustom(unsigned Opcode);
/// Reset any state between object emissions, i.e. the equivalent of
/// MCStreamer's reset method.
virtual void reset();
/// Callback used to implement the ldr= pseudo.
/// Add a new entry to the constant pool for the current section and return an
/// MCExpr that can be used to refer to the constant pool location.
const MCExpr *addConstantPoolEntry(const MCExpr *, SMLoc Loc);
/// Callback used to implement the .ltorg directive.
/// Emit contents of constant pool for the current section.
void emitCurrentConstantPool();
private:
std::unique_ptr<AssemblerConstantPools> ConstantPools;
};
/// Streaming machine code generation interface.
///
/// This interface is intended to provide a programmatic interface that is very
/// similar to the level that an assembler .s file provides. It has callbacks
/// to emit bytes, handle directives, etc. The implementation of this interface
/// retains state to know what the current section is etc.
///
/// There are multiple implementations of this interface: one for writing out
/// a .s file, and implementations that write out .o files of various formats.
///
class MCStreamer {
MCContext &Context;
std::unique_ptr<MCTargetStreamer> TargetStreamer;
std::vector<MCDwarfFrameInfo> DwarfFrameInfos;
MCDwarfFrameInfo *getCurrentDwarfFrameInfo();
/// Similar to DwarfFrameInfos, but for SEH unwind info. Chained frames may
/// refer to each other, so use std::unique_ptr to provide pointer stability.
std::vector<std::unique_ptr<WinEH::FrameInfo>> WinFrameInfos;
WinEH::FrameInfo *CurrentWinFrameInfo;
size_t CurrentProcWinFrameInfoStartIndex;
/// Tracks an index to represent the order a symbol was emitted in.
/// Zero means we did not emit that symbol.
DenseMap<const MCSymbol *, unsigned> SymbolOrdering;
/// This is stack of current and previous section values saved by
/// pushSection.
SmallVector<std::pair<MCSectionSubPair, MCSectionSubPair>, 4> SectionStack;
/// Pointer to the parser's SMLoc if available. This is used to provide
/// locations for diagnostics.
const SMLoc *StartTokLocPtr = nullptr;
/// The next unique ID to use when creating a WinCFI-related section (.pdata
/// or .xdata). This ID ensures that we have a one-to-one mapping from
/// code section to unwind info section, which MSVC's incremental linker
/// requires.
unsigned NextWinCFIID = 0;
bool UseAssemblerInfoForParsing;
/// Is the assembler allowed to insert padding automatically? For
/// correctness reasons, we sometimes need to ensure instructions aren't
/// separated in unexpected ways. At the moment, this feature is only
/// useable from an integrated assembler, but assembly syntax is under
/// discussion for future inclusion.
bool AllowAutoPadding = false;
protected:
MCStreamer(MCContext &Ctx);
virtual void emitCFIStartProcImpl(MCDwarfFrameInfo &Frame);
virtual void emitCFIEndProcImpl(MCDwarfFrameInfo &CurFrame);
WinEH::FrameInfo *getCurrentWinFrameInfo() {
return CurrentWinFrameInfo;
}
virtual void emitWindowsUnwindTables(WinEH::FrameInfo *Frame);
virtual void emitWindowsUnwindTables();
virtual void emitRawTextImpl(StringRef String);
/// Returns true if the the .cv_loc directive is in the right section.
bool checkCVLocSection(unsigned FuncId, unsigned FileNo, SMLoc Loc);
public:
MCStreamer(const MCStreamer &) = delete;
MCStreamer &operator=(const MCStreamer &) = delete;
virtual ~MCStreamer();
void visitUsedExpr(const MCExpr &Expr);
virtual void visitUsedSymbol(const MCSymbol &Sym);
void setTargetStreamer(MCTargetStreamer *TS) {
TargetStreamer.reset(TS);
}
void setStartTokLocPtr(const SMLoc *Loc) { StartTokLocPtr = Loc; }
SMLoc getStartTokLoc() const {
return StartTokLocPtr ? *StartTokLocPtr : SMLoc();
}
/// State management
///
virtual void reset();
MCContext &getContext() const { return Context; }
virtual MCAssembler *getAssemblerPtr() { return nullptr; }
void setUseAssemblerInfoForParsing(bool v) { UseAssemblerInfoForParsing = v; }
bool getUseAssemblerInfoForParsing() { return UseAssemblerInfoForParsing; }
MCTargetStreamer *getTargetStreamer() {
return TargetStreamer.get();
}
void setAllowAutoPadding(bool v) { AllowAutoPadding = v; }
bool getAllowAutoPadding() const { return AllowAutoPadding; }
/// When emitting an object file, create and emit a real label. When emitting
/// textual assembly, this should do nothing to avoid polluting our output.
virtual MCSymbol *emitCFILabel();
/// Retrieve the current frame info if one is available and it is not yet
/// closed. Otherwise, issue an error and return null.
WinEH::FrameInfo *EnsureValidWinFrameInfo(SMLoc Loc);
unsigned getNumFrameInfos();
ArrayRef<MCDwarfFrameInfo> getDwarfFrameInfos() const;
bool hasUnfinishedDwarfFrameInfo();
unsigned getNumWinFrameInfos() { return WinFrameInfos.size(); }
ArrayRef<std::unique_ptr<WinEH::FrameInfo>> getWinFrameInfos() const {
return WinFrameInfos;
}
void generateCompactUnwindEncodings(MCAsmBackend *MAB);
/// \name Assembly File Formatting.
/// @{
/// Return true if this streamer supports verbose assembly and if it is
/// enabled.
virtual bool isVerboseAsm() const { return false; }
/// Return true if this asm streamer supports emitting unformatted text
/// to the .s file with EmitRawText.
virtual bool hasRawTextSupport() const { return false; }
/// Is the integrated assembler required for this streamer to function
/// correctly?
virtual bool isIntegratedAssemblerRequired() const { return false; }
/// Add a textual comment.
///
/// Typically for comments that can be emitted to the generated .s
/// file if applicable as a QoI issue to make the output of the compiler
/// more readable. This only affects the MCAsmStreamer, and only when
/// verbose assembly output is enabled.
///
/// If the comment includes embedded \n's, they will each get the comment
/// prefix as appropriate. The added comment should not end with a \n.
/// By default, each comment is terminated with an end of line, i.e. the
/// EOL param is set to true by default. If one prefers not to end the
/// comment with a new line then the EOL param should be passed
/// with a false value.
virtual void AddComment(const Twine &T, bool EOL = true) {}
/// Return a raw_ostream that comments can be written to. Unlike
/// AddComment, you are required to terminate comments with \n if you use this
/// method.
virtual raw_ostream &getCommentOS();
/// Print T and prefix it with the comment string (normally #) and
/// optionally a tab. This prints the comment immediately, not at the end of
/// the current line. It is basically a safe version of EmitRawText: since it
/// only prints comments, the object streamer ignores it instead of asserting.
virtual void emitRawComment(const Twine &T, bool TabPrefix = true);
/// Add explicit comment T. T is required to be a valid
/// comment in the output and does not need to be escaped.
virtual void addExplicitComment(const Twine &T);
/// Emit added explicit comments.
virtual void emitExplicitComments();
/// Emit a blank line to a .s file to pretty it up.
virtual void addBlankLine() {}
/// @}
/// \name Symbol & Section Management
/// @{
/// Return the current section that the streamer is emitting code to.
MCSectionSubPair getCurrentSection() const {
if (!SectionStack.empty())
return SectionStack.back().first;
return MCSectionSubPair();
}
MCSection *getCurrentSectionOnly() const { return getCurrentSection().first; }
/// Return the previous section that the streamer is emitting code to.
MCSectionSubPair getPreviousSection() const {
if (!SectionStack.empty())
return SectionStack.back().second;
return MCSectionSubPair();
}
/// Returns an index to represent the order a symbol was emitted in.
/// (zero if we did not emit that symbol)
unsigned getSymbolOrder(const MCSymbol *Sym) const {
return SymbolOrdering.lookup(Sym);
}
/// Update streamer for a new active section.
///
/// This is called by popSection and switchSection, if the current
/// section changes.
virtual void changeSection(MCSection *, const MCExpr *);
/// Save the current and previous section on the section stack.
void pushSection() {
SectionStack.push_back(
std::make_pair(getCurrentSection(), getPreviousSection()));
}
/// Restore the current and previous section from the section stack.
/// Calls changeSection as needed.
///
/// Returns false if the stack was empty.
bool popSection() {
if (SectionStack.size() <= 1)
return false;
auto I = SectionStack.end();
--I;
MCSectionSubPair OldSection = I->first;
--I;
MCSectionSubPair NewSection = I->first;
if (NewSection.first && OldSection != NewSection)
changeSection(NewSection.first, NewSection.second);
SectionStack.pop_back();
return true;
}
bool subSection(const MCExpr *Subsection) {
if (SectionStack.empty())
return false;
switchSection(SectionStack.back().first.first, Subsection);
return true;
}
/// Set the current section where code is being emitted to \p Section. This
/// is required to update CurSection.
///
/// This corresponds to assembler directives like .section, .text, etc.
virtual void switchSection(MCSection *Section,
const MCExpr *Subsection = nullptr);
/// Set the current section where code is being emitted to \p Section.
/// This is required to update CurSection. This version does not call
/// changeSection.
void switchSectionNoChange(MCSection *Section,
const MCExpr *Subsection = nullptr) {
assert(Section && "Cannot switch to a null section!");
MCSectionSubPair curSection = SectionStack.back().first;
SectionStack.back().second = curSection;
if (MCSectionSubPair(Section, Subsection) != curSection)
SectionStack.back().first = MCSectionSubPair(Section, Subsection);
}
/// Create the default sections and set the initial one.
virtual void initSections(bool NoExecStack, const MCSubtargetInfo &STI);
MCSymbol *endSection(MCSection *Section);
/// Sets the symbol's section.
///
/// Each emitted symbol will be tracked in the ordering table,
/// so we can sort on them later.
void assignFragment(MCSymbol *Symbol, MCFragment *Fragment);
/// Returns the mnemonic for \p MI, if the streamer has access to a
/// instruction printer and returns an empty string otherwise.
virtual StringRef getMnemonic(MCInst &MI) { return ""; }
/// Emit a label for \p Symbol into the current section.
///
/// This corresponds to an assembler statement such as:
/// foo:
///
/// \param Symbol - The symbol to emit. A given symbol should only be
/// emitted as a label once, and symbols emitted as a label should never be
/// used in an assignment.
// FIXME: These emission are non-const because we mutate the symbol to
// add the section we're emitting it to later.
virtual void emitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc());
virtual void emitEHSymAttributes(const MCSymbol *Symbol, MCSymbol *EHSymbol);
/// Note in the output the specified \p Flag.
virtual void emitAssemblerFlag(MCAssemblerFlag Flag);
/// Emit the given list \p Options of strings as linker
/// options into the output.
virtual void emitLinkerOptions(ArrayRef<std::string> Kind) {}
/// Note in the output the specified region \p Kind.
virtual void emitDataRegion(MCDataRegionType Kind) {}
/// Specify the Mach-O minimum deployment target version.
virtual void emitVersionMin(MCVersionMinType Type, unsigned Major,
unsigned Minor, unsigned Update,
VersionTuple SDKVersion) {}
/// Emit/Specify Mach-O build version command.
/// \p Platform should be one of MachO::PlatformType.
virtual void emitBuildVersion(unsigned Platform, unsigned Major,
unsigned Minor, unsigned Update,
VersionTuple SDKVersion) {}
virtual void emitDarwinTargetVariantBuildVersion(unsigned Platform,
unsigned Major,
unsigned Minor,
unsigned Update,
VersionTuple SDKVersion) {}
void emitVersionForTarget(const Triple &Target,
const VersionTuple &SDKVersion,
const Triple *DarwinTargetVariantTriple,
const VersionTuple &DarwinTargetVariantSDKVersion);
/// Note in the output that the specified \p Func is a Thumb mode
/// function (ARM target only).
virtual void emitThumbFunc(MCSymbol *Func);
/// Emit an assignment of \p Value to \p Symbol.
///
/// This corresponds to an assembler statement such as:
/// symbol = value
///
/// The assignment generates no code, but has the side effect of binding the
/// value in the current context. For the assembly streamer, this prints the
/// binding into the .s file.
///
/// \param Symbol - The symbol being assigned to.
/// \param Value - The value for the symbol.
virtual void emitAssignment(MCSymbol *Symbol, const MCExpr *Value);
/// Emit an assignment of \p Value to \p Symbol, but only if \p Value is also
/// emitted.
virtual void emitConditionalAssignment(MCSymbol *Symbol, const MCExpr *Value);
/// Emit an weak reference from \p Alias to \p Symbol.
///
/// This corresponds to an assembler statement such as:
/// .weakref alias, symbol
///
/// \param Alias - The alias that is being created.
/// \param Symbol - The symbol being aliased.
virtual void emitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);
/// Add the given \p Attribute to \p Symbol.
virtual bool emitSymbolAttribute(MCSymbol *Symbol,
MCSymbolAttr Attribute) = 0;
/// Set the \p DescValue for the \p Symbol.
///
/// \param Symbol - The symbol to have its n_desc field set.
/// \param DescValue - The value to set into the n_desc field.
virtual void emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
/// Start emitting COFF symbol definition
///
/// \param Symbol - The symbol to have its External & Type fields set.
virtual void beginCOFFSymbolDef(const MCSymbol *Symbol);
/// Emit the storage class of the symbol.
///
/// \param StorageClass - The storage class the symbol should have.
virtual void emitCOFFSymbolStorageClass(int StorageClass);
/// Emit the type of the symbol.
///
/// \param Type - A COFF type identifier (see COFF::SymbolType in X86COFF.h)
virtual void emitCOFFSymbolType(int Type);
/// Marks the end of the symbol definition.
virtual void endCOFFSymbolDef();
virtual void emitCOFFSafeSEH(MCSymbol const *Symbol);
/// Emits the symbol table index of a Symbol into the current section.
virtual void emitCOFFSymbolIndex(MCSymbol const *Symbol);
/// Emits a COFF section index.
///
/// \param Symbol - Symbol the section number relocation should point to.
virtual void emitCOFFSectionIndex(MCSymbol const *Symbol);
/// Emits a COFF section relative relocation.
///
/// \param Symbol - Symbol the section relative relocation should point to.
virtual void emitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset);
/// Emits a COFF image relative relocation.
///
/// \param Symbol - Symbol the image relative relocation should point to.
virtual void emitCOFFImgRel32(MCSymbol const *Symbol, int64_t Offset);
/// Emits an lcomm directive with XCOFF csect information.
///
/// \param LabelSym - Label on the block of storage.
/// \param Size - The size of the block of storage.
/// \param CsectSym - Csect name for the block of storage.
/// \param Alignment - The alignment of the symbol in bytes.
virtual void emitXCOFFLocalCommonSymbol(MCSymbol *LabelSym, uint64_t Size,
MCSymbol *CsectSym, Align Alignment);
/// Emit a symbol's linkage and visibility with a linkage directive for XCOFF.
///
/// \param Symbol - The symbol to emit.
/// \param Linkage - The linkage of the symbol to emit.
/// \param Visibility - The visibility of the symbol to emit or MCSA_Invalid
/// if the symbol does not have an explicit visibility.
virtual void emitXCOFFSymbolLinkageWithVisibility(MCSymbol *Symbol,
MCSymbolAttr Linkage,
MCSymbolAttr Visibility);
/// Emit a XCOFF .rename directive which creates a synonym for an illegal or
/// undesirable name.
///
/// \param Name - The name used internally in the assembly for references to
/// the symbol.
/// \param Rename - The value to which the Name parameter is
/// changed at the end of assembly.
virtual void emitXCOFFRenameDirective(const MCSymbol *Name, StringRef Rename);
/// Emit an XCOFF .except directive which adds information about
/// a trap instruction to the object file exception section
///
/// \param Symbol - The function containing the trap.
/// \param Lang - The language code for the exception entry.
/// \param Reason - The reason code for the exception entry.
virtual void emitXCOFFExceptDirective(const MCSymbol *Symbol,
const MCSymbol *Trap,
unsigned Lang, unsigned Reason,
unsigned FunctionSize, bool hasDebug);
/// Emit a XCOFF .ref directive which creates R_REF type entry in the
/// relocation table for one or more symbols.
///
/// \param Sym - The symbol on the .ref directive.
virtual void emitXCOFFRefDirective(StringRef Sym);
/// Emit an ELF .size directive.
///
/// This corresponds to an assembler statement such as:
/// .size symbol, expression
virtual void emitELFSize(MCSymbol *Symbol, const MCExpr *Value);
/// Emit an ELF .symver directive.
///
/// This corresponds to an assembler statement such as:
/// .symver _start, foo@@SOME_VERSION
virtual void emitELFSymverDirective(const MCSymbol *OriginalSym,
StringRef Name, bool KeepOriginalSym);
/// Emit a Linker Optimization Hint (LOH) directive.
/// \param Args - Arguments of the LOH.
virtual void emitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) {}
/// Emit a .gnu_attribute directive.
virtual void emitGNUAttribute(unsigned Tag, unsigned Value) {}
/// Emit a common symbol.
///
/// \param Symbol - The common symbol to emit.
/// \param Size - The size of the common symbol.
/// \param ByteAlignment - The alignment of the symbol.
virtual void emitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
Align ByteAlignment) = 0;
/// Emit a local common (.lcomm) symbol.
///
/// \param Symbol - The common symbol to emit.
/// \param Size - The size of the common symbol.
/// \param ByteAlignment - The alignment of the common symbol in bytes.
virtual void emitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
Align ByteAlignment);
/// Emit the zerofill section and an optional symbol.
///
/// \param Section - The zerofill section to create and or to put the symbol
/// \param Symbol - The zerofill symbol to emit, if non-NULL.
/// \param Size - The size of the zerofill symbol.
/// \param ByteAlignment - The alignment of the zerofill symbol.
virtual void emitZerofill(MCSection *Section, MCSymbol *Symbol = nullptr,
uint64_t Size = 0, Align ByteAlignment = Align(1),
SMLoc Loc = SMLoc()) = 0;
/// Emit a thread local bss (.tbss) symbol.
///
/// \param Section - The thread local common section.
/// \param Symbol - The thread local common symbol to emit.
/// \param Size - The size of the symbol.
/// \param ByteAlignment - The alignment of the thread local common symbol.
virtual void emitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
uint64_t Size, Align ByteAlignment = Align(1));
/// @}
/// \name Generating Data
/// @{
/// Emit the bytes in \p Data into the output.
///
/// This is used to implement assembler directives such as .byte, .ascii,
/// etc.
virtual void emitBytes(StringRef Data);
/// Functionally identical to EmitBytes. When emitting textual assembly, this
/// method uses .byte directives instead of .ascii or .asciz for readability.
virtual void emitBinaryData(StringRef Data);
/// Emit the expression \p Value into the output as a native
/// integer of the given \p Size bytes.
///
/// This is used to implement assembler directives such as .word, .quad,
/// etc.
///
/// \param Value - The value to emit.
/// \param Size - The size of the integer (in bytes) to emit. This must
/// match a native machine width.
/// \param Loc - The location of the expression for error reporting.
virtual void emitValueImpl(const MCExpr *Value, unsigned Size,
SMLoc Loc = SMLoc());
void emitValue(const MCExpr *Value, unsigned Size, SMLoc Loc = SMLoc());
/// Special case of EmitValue that avoids the client having
/// to pass in a MCExpr for constant integers.
virtual void emitIntValue(uint64_t Value, unsigned Size);
virtual void emitIntValue(APInt Value);
/// Special case of EmitValue that avoids the client having to pass
/// in a MCExpr for constant integers & prints in Hex format for certain
/// modes.
virtual void emitIntValueInHex(uint64_t Value, unsigned Size) {
emitIntValue(Value, Size);
}
void emitInt8(uint64_t Value) { emitIntValue(Value, 1); }
void emitInt16(uint64_t Value) { emitIntValue(Value, 2); }
void emitInt32(uint64_t Value) { emitIntValue(Value, 4); }
void emitInt64(uint64_t Value) { emitIntValue(Value, 8); }
/// Special case of EmitValue that avoids the client having to pass
/// in a MCExpr for constant integers & prints in Hex format for certain
/// modes, pads the field with leading zeros to Size width
virtual void emitIntValueInHexWithPadding(uint64_t Value, unsigned Size) {
emitIntValue(Value, Size);
}
virtual void emitULEB128Value(const MCExpr *Value);
virtual void emitSLEB128Value(const MCExpr *Value);
/// Special case of EmitULEB128Value that avoids the client having to
/// pass in a MCExpr for constant integers.
unsigned emitULEB128IntValue(uint64_t Value, unsigned PadTo = 0);
/// Special case of EmitSLEB128Value that avoids the client having to
/// pass in a MCExpr for constant integers.
unsigned emitSLEB128IntValue(int64_t Value);
/// Special case of EmitValue that avoids the client having to pass in
/// a MCExpr for MCSymbols.
void emitSymbolValue(const MCSymbol *Sym, unsigned Size,
bool IsSectionRelative = false);
/// Emit the expression \p Value into the output as a dtprel
/// (64-bit DTP relative) value.
///
/// This is used to implement assembler directives such as .dtpreldword on
/// targets that support them.
virtual void emitDTPRel64Value(const MCExpr *Value);
/// Emit the expression \p Value into the output as a dtprel
/// (32-bit DTP relative) value.
///
/// This is used to implement assembler directives such as .dtprelword on
/// targets that support them.
virtual void emitDTPRel32Value(const MCExpr *Value);
/// Emit the expression \p Value into the output as a tprel
/// (64-bit TP relative) value.
///
/// This is used to implement assembler directives such as .tpreldword on
/// targets that support them.
virtual void emitTPRel64Value(const MCExpr *Value);
/// Emit the expression \p Value into the output as a tprel
/// (32-bit TP relative) value.
///
/// This is used to implement assembler directives such as .tprelword on
/// targets that support them.
virtual void emitTPRel32Value(const MCExpr *Value);
/// Emit the expression \p Value into the output as a gprel64 (64-bit
/// GP relative) value.
///
/// This is used to implement assembler directives such as .gpdword on
/// targets that support them.
virtual void emitGPRel64Value(const MCExpr *Value);
/// Emit the expression \p Value into the output as a gprel32 (32-bit
/// GP relative) value.
///
/// This is used to implement assembler directives such as .gprel32 on
/// targets that support them.
virtual void emitGPRel32Value(const MCExpr *Value);
/// Emit NumBytes bytes worth of the value specified by FillValue.
/// This implements directives such as '.space'.
void emitFill(uint64_t NumBytes, uint8_t FillValue);
/// Emit \p Size bytes worth of the value specified by \p FillValue.
///
/// This is used to implement assembler directives such as .space or .skip.
///
/// \param NumBytes - The number of bytes to emit.
/// \param FillValue - The value to use when filling bytes.
/// \param Loc - The location of the expression for error reporting.
virtual void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
SMLoc Loc = SMLoc());
/// Emit \p NumValues copies of \p Size bytes. Each \p Size bytes is
/// taken from the lowest order 4 bytes of \p Expr expression.
///
/// This is used to implement assembler directives such as .fill.
///
/// \param NumValues - The number of copies of \p Size bytes to emit.
/// \param Size - The size (in bytes) of each repeated value.
/// \param Expr - The expression from which \p Size bytes are used.
virtual void emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
SMLoc Loc = SMLoc());
virtual void emitNops(int64_t NumBytes, int64_t ControlledNopLength,
SMLoc Loc, const MCSubtargetInfo& STI);
/// Emit NumBytes worth of zeros.
/// This function properly handles data in virtual sections.
void emitZeros(uint64_t NumBytes);
/// Emit some number of copies of \p Value until the byte alignment \p
/// ByteAlignment is reached.
///
/// If the number of bytes need to emit for the alignment is not a multiple
/// of \p ValueSize, then the contents of the emitted fill bytes is
/// undefined.
///
/// This used to implement the .align assembler directive.
///
/// \param Alignment - The alignment to reach.
/// \param Value - The value to use when filling bytes.
/// \param ValueSize - The size of the integer (in bytes) to emit for
/// \p Value. This must match a native machine width.
/// \param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
/// the alignment cannot be reached in this many bytes, no bytes are
/// emitted.
virtual void emitValueToAlignment(Align Alignment, int64_t Value = 0,
unsigned ValueSize = 1,
unsigned MaxBytesToEmit = 0);
/// Emit nops until the byte alignment \p ByteAlignment is reached.
///
/// This used to align code where the alignment bytes may be executed. This
/// can emit different bytes for different sizes to optimize execution.
///
/// \param Alignment - The alignment to reach.
/// \param STI - The MCSubtargetInfo in operation when padding is emitted.
/// \param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
/// the alignment cannot be reached in this many bytes, no bytes are
/// emitted.
virtual void emitCodeAlignment(Align Alignment, const MCSubtargetInfo *STI,
unsigned MaxBytesToEmit = 0);
/// Emit some number of copies of \p Value until the byte offset \p
/// Offset is reached.
///
/// This is used to implement assembler directives such as .org.
///
/// \param Offset - The offset to reach. This may be an expression, but the
/// expression must be associated with the current section.
/// \param Value - The value to use when filling bytes.
virtual void emitValueToOffset(const MCExpr *Offset, unsigned char Value,
SMLoc Loc);
/// @}
/// Switch to a new logical file. This is used to implement the '.file
/// "foo.c"' assembler directive.
virtual void emitFileDirective(StringRef Filename);
/// Emit ".file assembler diretive with additioal info.
virtual void emitFileDirective(StringRef Filename, StringRef CompilerVerion,
StringRef TimeStamp, StringRef Description);
/// Emit the "identifiers" directive. This implements the
/// '.ident "version foo"' assembler directive.
virtual void emitIdent(StringRef IdentString) {}
/// Associate a filename with a specified logical file number. This
/// implements the DWARF2 '.file 4 "foo.c"' assembler directive.
unsigned emitDwarfFileDirective(
unsigned FileNo, StringRef Directory, StringRef Filename,
std::optional<MD5::MD5Result> Checksum = std::nullopt,
std::optional<StringRef> Source = std::nullopt, unsigned CUID = 0) {
return cantFail(
tryEmitDwarfFileDirective(FileNo, Directory, Filename, Checksum,
Source, CUID));
}
/// Associate a filename with a specified logical file number.
/// Also associate a directory, optional checksum, and optional source
/// text with the logical file. This implements the DWARF2
/// '.file 4 "dir/foo.c"' assembler directive, and the DWARF5
/// '.file 4 "dir/foo.c" md5 "..." source "..."' assembler directive.
virtual Expected<unsigned> tryEmitDwarfFileDirective(
unsigned FileNo, StringRef Directory, StringRef Filename,
std::optional<MD5::MD5Result> Checksum = std::nullopt,
std::optional<StringRef> Source = std::nullopt, unsigned CUID = 0);
/// Specify the "root" file of the compilation, using the ".file 0" extension.
virtual void emitDwarfFile0Directive(StringRef Directory, StringRef Filename,
std::optional<MD5::MD5Result> Checksum,
std::optional<StringRef> Source,
unsigned CUID = 0);
virtual void emitCFIBKeyFrame();
virtual void emitCFIMTETaggedFrame();
/// This implements the DWARF2 '.loc fileno lineno ...' assembler
/// directive.
virtual void emitDwarfLocDirective(unsigned FileNo, unsigned Line,
unsigned Column, unsigned Flags,
unsigned Isa, unsigned Discriminator,
StringRef FileName);
/// Associate a filename with a specified logical file number, and also
/// specify that file's checksum information. This implements the '.cv_file 4
/// "foo.c"' assembler directive. Returns true on success.
virtual bool emitCVFileDirective(unsigned FileNo, StringRef Filename,
ArrayRef<uint8_t> Checksum,
unsigned ChecksumKind);
/// Introduces a function id for use with .cv_loc.
virtual bool emitCVFuncIdDirective(unsigned FunctionId);
/// Introduces an inline call site id for use with .cv_loc. Includes
/// extra information for inline line table generation.
virtual bool emitCVInlineSiteIdDirective(unsigned FunctionId, unsigned IAFunc,
unsigned IAFile, unsigned IALine,
unsigned IACol, SMLoc Loc);
/// This implements the CodeView '.cv_loc' assembler directive.
virtual void emitCVLocDirective(unsigned FunctionId, unsigned FileNo,
unsigned Line, unsigned Column,
bool PrologueEnd, bool IsStmt,
StringRef FileName, SMLoc Loc);
/// This implements the CodeView '.cv_linetable' assembler directive.
virtual void emitCVLinetableDirective(unsigned FunctionId,
const MCSymbol *FnStart,
const MCSymbol *FnEnd);
/// This implements the CodeView '.cv_inline_linetable' assembler
/// directive.
virtual void emitCVInlineLinetableDirective(unsigned PrimaryFunctionId,
unsigned SourceFileId,
unsigned SourceLineNum,
const MCSymbol *FnStartSym,
const MCSymbol *FnEndSym);
/// This implements the CodeView '.cv_def_range' assembler
/// directive.
virtual void emitCVDefRangeDirective(
ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
StringRef FixedSizePortion);
virtual void emitCVDefRangeDirective(
ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
codeview::DefRangeRegisterRelHeader DRHdr);
virtual void emitCVDefRangeDirective(
ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
codeview::DefRangeSubfieldRegisterHeader DRHdr);
virtual void emitCVDefRangeDirective(
ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
codeview::DefRangeRegisterHeader DRHdr);
virtual void emitCVDefRangeDirective(
ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
codeview::DefRangeFramePointerRelHeader DRHdr);
/// This implements the CodeView '.cv_stringtable' assembler directive.
virtual void emitCVStringTableDirective() {}
/// This implements the CodeView '.cv_filechecksums' assembler directive.
virtual void emitCVFileChecksumsDirective() {}
/// This implements the CodeView '.cv_filechecksumoffset' assembler
/// directive.
virtual void emitCVFileChecksumOffsetDirective(unsigned FileNo) {}
/// This implements the CodeView '.cv_fpo_data' assembler directive.
virtual void emitCVFPOData(const MCSymbol *ProcSym, SMLoc Loc = {}) {}
/// Emit the absolute difference between two symbols.
///
/// \pre Offset of \c Hi is greater than the offset \c Lo.
virtual void emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo,
unsigned Size);
/// Emit the absolute difference between two symbols encoded with ULEB128.
virtual void emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi,
const MCSymbol *Lo);
virtual MCSymbol *getDwarfLineTableSymbol(unsigned CUID);
virtual void emitCFISections(bool EH, bool Debug);
void emitCFIStartProc(bool IsSimple, SMLoc Loc = SMLoc());
void emitCFIEndProc();
virtual void emitCFIDefCfa(int64_t Register, int64_t Offset);
virtual void emitCFIDefCfaOffset(int64_t Offset);
virtual void emitCFIDefCfaRegister(int64_t Register);
virtual void emitCFILLVMDefAspaceCfa(int64_t Register, int64_t Offset,
int64_t AddressSpace);
virtual void emitCFIOffset(int64_t Register, int64_t Offset);
virtual void emitCFIPersonality(const MCSymbol *Sym, unsigned Encoding);
virtual void emitCFILsda(const MCSymbol *Sym, unsigned Encoding);
virtual void emitCFIRememberState();
virtual void emitCFIRestoreState();
virtual void emitCFISameValue(int64_t Register);
virtual void emitCFIRestore(int64_t Register);
virtual void emitCFIRelOffset(int64_t Register, int64_t Offset);
virtual void emitCFIAdjustCfaOffset(int64_t Adjustment);
virtual void emitCFIEscape(StringRef Values);
virtual void emitCFIReturnColumn(int64_t Register);
virtual void emitCFIGnuArgsSize(int64_t Size);
virtual void emitCFISignalFrame();
virtual void emitCFIUndefined(int64_t Register);
virtual void emitCFIRegister(int64_t Register1, int64_t Register2);
virtual void emitCFIWindowSave();
virtual void emitCFINegateRAState();
virtual void emitWinCFIStartProc(const MCSymbol *Symbol, SMLoc Loc = SMLoc());
virtual void emitWinCFIEndProc(SMLoc Loc = SMLoc());
/// This is used on platforms, such as Windows on ARM64, that require function
/// or funclet sizes to be emitted in .xdata before the End marker is emitted
/// for the frame. We cannot use the End marker, as it is not set at the
/// point of emitting .xdata, in order to indicate that the frame is active.
virtual void emitWinCFIFuncletOrFuncEnd(SMLoc Loc = SMLoc());
virtual void emitWinCFIStartChained(SMLoc Loc = SMLoc());
virtual void emitWinCFIEndChained(SMLoc Loc = SMLoc());
virtual void emitWinCFIPushReg(MCRegister Register, SMLoc Loc = SMLoc());
virtual void emitWinCFISetFrame(MCRegister Register, unsigned Offset,
SMLoc Loc = SMLoc());
virtual void emitWinCFIAllocStack(unsigned Size, SMLoc Loc = SMLoc());
virtual void emitWinCFISaveReg(MCRegister Register, unsigned Offset,
SMLoc Loc = SMLoc());
virtual void emitWinCFISaveXMM(MCRegister Register, unsigned Offset,
SMLoc Loc = SMLoc());
virtual void emitWinCFIPushFrame(bool Code, SMLoc Loc = SMLoc());
virtual void emitWinCFIEndProlog(SMLoc Loc = SMLoc());
virtual void emitWinEHHandler(const MCSymbol *Sym, bool Unwind, bool Except,
SMLoc Loc = SMLoc());
virtual void emitWinEHHandlerData(SMLoc Loc = SMLoc());
virtual void emitCGProfileEntry(const MCSymbolRefExpr *From,
const MCSymbolRefExpr *To, uint64_t Count);
/// Get the .pdata section used for the given section. Typically the given
/// section is either the main .text section or some other COMDAT .text
/// section, but it may be any section containing code.
MCSection *getAssociatedPDataSection(const MCSection *TextSec);
/// Get the .xdata section used for the given section.
MCSection *getAssociatedXDataSection(const MCSection *TextSec);
virtual void emitSyntaxDirective();
/// Record a relocation described by the .reloc directive. Return std::nullopt
/// if succeeded. Otherwise, return a pair (Name is invalid, error message).
virtual std::optional<std::pair<bool, std::string>>
emitRelocDirective(const MCExpr &Offset, StringRef Name, const MCExpr *Expr,
SMLoc Loc, const MCSubtargetInfo &STI) {
return std::nullopt;
}
virtual void emitAddrsig() {}
virtual void emitAddrsigSym(const MCSymbol *Sym) {}
/// Emit the given \p Instruction into the current section.
virtual void emitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI);
/// Emit the a pseudo probe into the current section.
virtual void emitPseudoProbe(uint64_t Guid, uint64_t Index, uint64_t Type,
uint64_t Attr,
const MCPseudoProbeInlineStack &InlineStack,
MCSymbol *FnSym);
/// Set the bundle alignment mode from now on in the section.
/// The value 1 means turn the bundle alignment off.
virtual void emitBundleAlignMode(Align Alignment);
/// The following instructions are a bundle-locked group.
///
/// \param AlignToEnd - If true, the bundle-locked group will be aligned to
/// the end of a bundle.
virtual void emitBundleLock(bool AlignToEnd);
/// Ends a bundle-locked group.
virtual void emitBundleUnlock();
/// If this file is backed by a assembly streamer, this dumps the
/// specified string in the output .s file. This capability is indicated by
/// the hasRawTextSupport() predicate. By default this aborts.
void emitRawText(const Twine &String);
/// Streamer specific finalization.
virtual void finishImpl();
/// Finish emission of machine code.
void finish(SMLoc EndLoc = SMLoc());
virtual bool mayHaveInstructions(MCSection &Sec) const { return true; }
/// Emit a special value of 0xffffffff if producing 64-bit debugging info.
void maybeEmitDwarf64Mark();
/// Emit a unit length field. The actual format, DWARF32 or DWARF64, is chosen
/// according to the settings.
virtual void emitDwarfUnitLength(uint64_t Length, const Twine &Comment);
/// Emit a unit length field. The actual format, DWARF32 or DWARF64, is chosen
/// according to the settings.
/// Return the end symbol generated inside, the caller needs to emit it.
virtual MCSymbol *emitDwarfUnitLength(const Twine &Prefix,
const Twine &Comment);
/// Emit the debug line start label.
virtual void emitDwarfLineStartLabel(MCSymbol *StartSym);
/// Emit the debug line end entry.
virtual void emitDwarfLineEndEntry(MCSection *Section, MCSymbol *LastLabel) {}
/// If targets does not support representing debug line section by .loc/.file
/// directives in assembly output, we need to populate debug line section with
/// raw debug line contents.
virtual void emitDwarfAdvanceLineAddr(int64_t LineDelta,
const MCSymbol *LastLabel,
const MCSymbol *Label,
unsigned PointerSize) {}
/// Do finalization for the streamer at the end of a section.
virtual void doFinalizationAtSectionEnd(MCSection *Section) {}
};
/// Create a dummy machine code streamer, which does nothing. This is useful for
/// timing the assembler front end.
MCStreamer *createNullStreamer(MCContext &Ctx);
} // end namespace llvm
#endif // LLVM_MC_MCSTREAMER_H