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mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-02 00:42:52 +01:00
llvm-mirror/include/llvm/Target/TargetLoweringObjectFile.h
Chris Lattner 48bdeff884 move emitUsedDirectiveFor to TargetLoweringObjectFile and rename it to
indicate that it is a predicate, not an emitter.  This eliminates TAI
dependencies on Mangler and GlobalValue.

llvm-svn: 77726
2009-07-31 20:52:39 +00:00

403 lines
14 KiB
C++

//===-- llvm/Target/TargetLoweringObjectFile.h - Object Info ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements classes used to handle lowerings specific to common
// object file formats.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H
#define LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
namespace llvm {
class MCSection;
class MCContext;
class GlobalValue;
class Mangler;
class TargetMachine;
/// SectionKind - This is a simple POD value that classifies the properties of
/// a section. A global variable is classified into the deepest possible
/// classification, and then the target maps them onto their sections based on
/// what capabilities they have.
///
/// The comments below describe these as if they were an inheritance hierarchy
/// in order to explain the predicates below.
class SectionKind {
public:
enum Kind {
/// Metadata - Debug info sections or other metadata.
Metadata,
/// Text - Text section, used for functions and other executable code.
Text,
/// ReadOnly - Data that is never written to at program runtime by the
/// program or the dynamic linker. Things in the top-level readonly
/// SectionKind are not mergeable.
ReadOnly,
/// MergeableCString - This is a special section for nul-terminated
/// strings. The linker can unique the C strings, knowing their
/// semantics. Because it uniques based on the nul terminators, the
/// compiler can't put strings in this section that have embeded nuls
/// in them.
MergeableCString,
/// MergeableConst - These are sections for merging fixed-length
/// constants together. For example, this can be used to unique
/// constant pool entries etc.
MergeableConst,
/// MergeableConst4 - This is a section used by 4-byte constants,
/// for example, floats.
MergeableConst4,
/// MergeableConst8 - This is a section used by 8-byte constants,
/// for example, doubles.
MergeableConst8,
/// MergeableConst16 - This is a section used by 16-byte constants,
/// for example, vectors.
MergeableConst16,
/// Writeable - This is the base of all segments that need to be written
/// to during program runtime.
/// ThreadLocal - This is the base of all TLS segments. All TLS
/// objects must be writeable, otherwise there is no reason for them to
/// be thread local!
/// ThreadBSS - Zero-initialized TLS data objects.
ThreadBSS,
/// ThreadData - Initialized TLS data objects.
ThreadData,
/// GlobalWriteableData - Writeable data that is global (not thread
/// local).
/// BSS - Zero initialized writeable data.
BSS,
/// DataRel - This is the most general form of data that is written
/// to by the program, it can have random relocations to arbitrary
/// globals.
DataRel,
/// DataRelLocal - This is writeable data that has a non-zero
/// initializer and has relocations in it, but all of the
/// relocations are known to be within the final linked image
/// the global is linked into.
DataRelLocal,
/// DataNoRel - This is writeable data that has a non-zero
/// initializer, but whose initializer is known to have no
/// relocations.
DataNoRel,
/// ReadOnlyWithRel - These are global variables that are never
/// written to by the program, but that have relocations, so they
/// must be stuck in a writeable section so that the dynamic linker
/// can write to them. If it chooses to, the dynamic linker can
/// mark the pages these globals end up on as read-only after it is
/// done with its relocation phase.
ReadOnlyWithRel,
/// ReadOnlyWithRelLocal - This is data that is readonly by the
/// program, but must be writeable so that the dynamic linker
/// can perform relocations in it. This is used when we know
/// that all the relocations are to globals in this final
/// linked image.
ReadOnlyWithRelLocal
};
private:
Kind K : 6;
/// Weak - This is true if the referenced symbol is weak (i.e. linkonce,
/// weak, weak_odr, etc). This is orthogonal from the categorization.
bool Weak : 1;
/// ExplicitSection - This is true if the global had a section explicitly
/// specified on it.
bool ExplicitSection : 1;
public:
// FIXME: REMOVE.
Kind getKind() const { return K; }
bool isWeak() const { return Weak; }
bool hasExplicitSection() const { return ExplicitSection; }
bool isMetadata() const { return K == Metadata; }
bool isText() const { return K == Text; }
bool isReadOnly() const {
return K == ReadOnly || K == MergeableCString || isMergeableConst();
}
bool isMergeableCString() const { return K == MergeableCString; }
bool isMergeableConst() const {
return K == MergeableConst || K == MergeableConst4 ||
K == MergeableConst8 || K == MergeableConst16;
}
bool isMergeableConst4() const { return K == MergeableConst4; }
bool isMergeableConst8() const { return K == MergeableConst8; }
bool isMergeableConst16() const { return K == MergeableConst16; }
bool isWriteable() const {
return isThreadLocal() || isGlobalWriteableData();
}
bool isThreadLocal() const {
return K == ThreadData || K == ThreadBSS;
}
bool isThreadBSS() const { return K == ThreadBSS; }
bool isThreadData() const { return K == ThreadData; }
bool isGlobalWriteableData() const {
return isBSS() || isDataRel() || isReadOnlyWithRel();
}
bool isBSS() const { return K == BSS; }
bool isDataRel() const {
return K == DataRel || K == DataRelLocal || K == DataNoRel;
}
bool isDataRelLocal() const {
return K == DataRelLocal || K == DataNoRel;
}
bool isDataNoRel() const { return K == DataNoRel; }
bool isReadOnlyWithRel() const {
return K == ReadOnlyWithRel || K == ReadOnlyWithRelLocal;
}
bool isReadOnlyWithRelLocal() const {
return K == ReadOnlyWithRelLocal;
}
static SectionKind get(Kind K, bool isWeak = false,
bool hasExplicitSection = false) {
SectionKind Res;
Res.K = K;
Res.Weak = isWeak;
Res.ExplicitSection = hasExplicitSection;
return Res;
}
};
class TargetLoweringObjectFile {
MCContext *Ctx;
protected:
TargetLoweringObjectFile();
/// TextSection - Section directive for standard text.
///
const MCSection *TextSection; // Defaults to ".text".
/// DataSection - Section directive for standard data.
///
const MCSection *DataSection; // Defaults to ".data".
// FIXME: SINK THESE.
const MCSection *BSSSection_;
/// ReadOnlySection - This is the directive that is emitted to switch to a
/// read-only section for constant data (e.g. data declared const,
/// jump tables).
const MCSection *ReadOnlySection; // Defaults to NULL
/// TLSDataSection - Section directive for Thread Local data.
///
const MCSection *TLSDataSection; // Defaults to ".tdata".
/// TLSBSSSection - Section directive for Thread Local uninitialized data.
/// Null if this target doesn't support a BSS section.
///
const MCSection *TLSBSSSection; // Defaults to ".tbss".
const MCSection *CStringSection_;
public:
// FIXME: NONPUB.
const MCSection *getOrCreateSection(const char *Name,
bool isDirective,
SectionKind::Kind K) const;
public:
virtual ~TargetLoweringObjectFile();
/// Initialize - this method must be called before any actual lowering is
/// done. This specifies the current context for codegen, and gives the
/// lowering implementations a chance to set up their default sections.
virtual void Initialize(MCContext &ctx, const TargetMachine &TM) {
Ctx = &ctx;
}
const MCSection *getTextSection() const { return TextSection; }
const MCSection *getDataSection() const { return DataSection; }
/// shouldEmitUsedDirectiveFor - This hook allows targets to selectively
/// decide not to emit the UsedDirective for some symbols in llvm.used.
/// FIXME: REMOVE this (rdar://7071300)
virtual bool shouldEmitUsedDirectiveFor(const GlobalValue *GV,
Mangler *) const {
return (GV!=0);
}
/// getSectionForMergeableConstant - Given a mergeable constant with the
/// specified size and relocation information, return a section that it
/// should be placed in.
virtual const MCSection *
getSectionForMergeableConstant(SectionKind Kind) const;
/// getKindForNamedSection - If this target wants to be able to override
/// section flags based on the name of the section specified for a global
/// variable, it can implement this. This is used on ELF systems so that
/// ".tbss" gets the TLS bit set etc.
virtual SectionKind::Kind getKindForNamedSection(const char *Section,
SectionKind::Kind K) const{
return K;
}
/// SectionForGlobal - This method computes the appropriate section to emit
/// the specified global variable or function definition. This should not
/// be passed external (or available externally) globals.
const MCSection *SectionForGlobal(const GlobalValue *GV,
Mangler *Mang,
const TargetMachine &TM) const;
/// getSpecialCasedSectionGlobals - Allow the target to completely override
/// section assignment of a global.
/// FIXME: ELIMINATE this by making PIC16 implement ADDRESS with
/// getFlagsForNamedSection.
virtual const MCSection *
getSpecialCasedSectionGlobals(const GlobalValue *GV, Mangler *Mang,
SectionKind Kind) const {
return 0;
}
/// getSectionFlagsAsString - Turn the flags in the specified SectionKind
/// into a string that can be printed to the assembly file after the
/// ".section foo" part of a section directive.
virtual void getSectionFlagsAsString(SectionKind Kind,
SmallVectorImpl<char> &Str) const {
}
protected:
virtual const MCSection *
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const;
};
class TargetLoweringObjectFileELF : public TargetLoweringObjectFile {
bool AtIsCommentChar; // True if @ is the comment character on this target.
bool HasCrazyBSS;
public:
/// ELF Constructor - AtIsCommentChar is true if the CommentCharacter from TAI
/// is "@".
TargetLoweringObjectFileELF(bool atIsCommentChar = false,
// FIXME: REMOVE AFTER UNIQUING IS FIXED.
bool hasCrazyBSS = false)
: AtIsCommentChar(atIsCommentChar), HasCrazyBSS(hasCrazyBSS) {}
virtual void Initialize(MCContext &Ctx, const TargetMachine &TM);
/// getSectionForMergeableConstant - Given a mergeable constant with the
/// specified size and relocation information, return a section that it
/// should be placed in.
virtual const MCSection *
getSectionForMergeableConstant(SectionKind Kind) const;
virtual SectionKind::Kind getKindForNamedSection(const char *Section,
SectionKind::Kind K) const;
void getSectionFlagsAsString(SectionKind Kind,
SmallVectorImpl<char> &Str) const;
virtual const MCSection *
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const;
protected:
const MCSection *DataRelSection;
const MCSection *DataRelLocalSection;
const MCSection *DataRelROSection;
const MCSection *DataRelROLocalSection;
const MCSection *MergeableConst4Section;
const MCSection *MergeableConst8Section;
const MCSection *MergeableConst16Section;
};
class TargetLoweringObjectFileMachO : public TargetLoweringObjectFile {
const MCSection *TextCoalSection;
const MCSection *ConstTextCoalSection;
const MCSection *ConstDataCoalSection;
const MCSection *ConstDataSection;
const MCSection *DataCoalSection;
const MCSection *FourByteConstantSection;
const MCSection *EightByteConstantSection;
const MCSection *SixteenByteConstantSection;
public:
virtual void Initialize(MCContext &Ctx, const TargetMachine &TM);
virtual const MCSection *
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const;
virtual const MCSection *
getSectionForMergeableConstant(SectionKind Kind) const;
/// shouldEmitUsedDirectiveFor - This hook allows targets to selectively
/// decide not to emit the UsedDirective for some symbols in llvm.used.
/// FIXME: REMOVE this (rdar://7071300)
virtual bool shouldEmitUsedDirectiveFor(const GlobalValue *GV,
Mangler *) const;
};
class TargetLoweringObjectFileCOFF : public TargetLoweringObjectFile {
public:
virtual void Initialize(MCContext &Ctx, const TargetMachine &TM);
virtual void getSectionFlagsAsString(SectionKind Kind,
SmallVectorImpl<char> &Str) const;
virtual const MCSection *
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const;
};
} // end namespace llvm
#endif