llvm-6502/include/llvm/MC/MCSectionCOFF.h
Rafael Espindola 013321a0f9 Fix a few issues with comdat handling on COFF.
* Section association cannot use just the section name as many
sections can have the same name. With this patch, the comdat symbol in
an assoc section is interpreted to mean a symbol in the associated
section and the mapping is discovered from it.

* Comdat symbols were not being set correctly. Instead we were getting
whatever was output first for that section.

A consequence is that associative sections now must use .section to
set the association. Using .linkonce would not work since it is not
possible to change a sections comdat symbol (it is used to decide if
we should create a new section or reuse an existing one).

This includes r210298, which was reverted because it was asserting
on an associated section having the same comdat as the associated
section.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210367 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-06 19:26:12 +00:00

88 lines
3.0 KiB
C++

//===- MCSectionCOFF.h - COFF Machine Code Sections -------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the MCSectionCOFF class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCSECTIONCOFF_H
#define LLVM_MC_MCSECTIONCOFF_H
#include "llvm/ADT/StringRef.h"
#include "llvm/MC/MCSection.h"
#include "llvm/Support/COFF.h"
namespace llvm {
class MCSymbol;
/// MCSectionCOFF - This represents a section on Windows
class MCSectionCOFF : public MCSection {
// The memory for this string is stored in the same MCContext as *this.
StringRef SectionName;
// FIXME: The following fields should not be mutable, but are for now so
// the asm parser can honor the .linkonce directive.
/// Characteristics - This is the Characteristics field of a section,
/// drawn from the enums below.
mutable unsigned Characteristics;
/// The COMDAT symbol of this section. Only valid if this is a COMDAT
/// section. Two COMDAT sections are merged if they have the same
/// COMDAT symbol.
const MCSymbol *COMDATSymbol;
/// Selection - This is the Selection field for the section symbol, if
/// it is a COMDAT section (Characteristics & IMAGE_SCN_LNK_COMDAT) != 0
mutable int Selection;
private:
friend class MCContext;
MCSectionCOFF(StringRef Section, unsigned Characteristics,
const MCSymbol *COMDATSymbol, int Selection, SectionKind K)
: MCSection(SV_COFF, K), SectionName(Section),
Characteristics(Characteristics), COMDATSymbol(COMDATSymbol),
Selection(Selection) {
assert ((Characteristics & 0x00F00000) == 0 &&
"alignment must not be set upon section creation");
}
~MCSectionCOFF();
public:
/// ShouldOmitSectionDirective - Decides whether a '.section' directive
/// should be printed before the section name
bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;
StringRef getSectionName() const { return SectionName; }
std::string getLabelBeginName() const override {
return SectionName.str() + "_begin";
}
std::string getLabelEndName() const override {
return SectionName.str() + "_end";
}
unsigned getCharacteristics() const { return Characteristics; }
const MCSymbol *getCOMDATSymbol() const { return COMDATSymbol; }
int getSelection() const { return Selection; }
void setSelection(int Selection) const;
void PrintSwitchToSection(const MCAsmInfo &MAI, raw_ostream &OS,
const MCExpr *Subsection) const override;
bool UseCodeAlign() const override;
bool isVirtualSection() const override;
static bool classof(const MCSection *S) {
return S->getVariant() == SV_COFF;
}
};
} // end namespace llvm
#endif