llvm-6502/lib/MC/MCSectionELF.cpp
Rafael Espindola e0a2541eb7 Add r228980 back.
Add support for having multiple sections with the same name and comdat.

Using this in combination with -ffunction-sections allows LLVM to output a .o
file with mulitple sections named .text. This saves space by avoiding long
unique names of the form .text.<C++ mangled name>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229541 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-17 20:48:01 +00:00

167 lines
4.1 KiB
C++

//===- lib/MC/MCSectionELF.cpp - ELF Code Section Representation ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
MCSectionELF::~MCSectionELF() {} // anchor.
// Decides whether a '.section' directive
// should be printed before the section name.
bool MCSectionELF::ShouldOmitSectionDirective(StringRef Name,
const MCAsmInfo &MAI) const {
if (Unique)
return false;
// FIXME: Does .section .bss/.data/.text work everywhere??
if (Name == ".text" || Name == ".data" ||
(Name == ".bss" && !MAI.usesELFSectionDirectiveForBSS()))
return true;
return false;
}
static void printName(raw_ostream &OS, StringRef Name) {
if (Name.find_first_not_of("0123456789_."
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ") == Name.npos) {
OS << Name;
return;
}
OS << '"';
for (const char *B = Name.begin(), *E = Name.end(); B < E; ++B) {
if (*B == '"') // Unquoted "
OS << "\\\"";
else if (*B != '\\') // Neither " or backslash
OS << *B;
else if (B + 1 == E) // Trailing backslash
OS << "\\\\";
else {
OS << B[0] << B[1]; // Quoted character
++B;
}
}
OS << '"';
}
void MCSectionELF::PrintSwitchToSection(const MCAsmInfo &MAI,
raw_ostream &OS,
const MCExpr *Subsection) const {
if (ShouldOmitSectionDirective(SectionName, MAI)) {
OS << '\t' << getSectionName();
if (Subsection)
OS << '\t' << *Subsection;
OS << '\n';
return;
}
OS << "\t.section\t";
printName(OS, getSectionName());
// Handle the weird solaris syntax if desired.
if (MAI.usesSunStyleELFSectionSwitchSyntax() &&
!(Flags & ELF::SHF_MERGE)) {
if (Flags & ELF::SHF_ALLOC)
OS << ",#alloc";
if (Flags & ELF::SHF_EXECINSTR)
OS << ",#execinstr";
if (Flags & ELF::SHF_WRITE)
OS << ",#write";
if (Flags & ELF::SHF_EXCLUDE)
OS << ",#exclude";
if (Flags & ELF::SHF_TLS)
OS << ",#tls";
OS << '\n';
return;
}
OS << ",\"";
if (Flags & ELF::SHF_ALLOC)
OS << 'a';
if (Flags & ELF::SHF_EXCLUDE)
OS << 'e';
if (Flags & ELF::SHF_EXECINSTR)
OS << 'x';
if (Flags & ELF::SHF_GROUP)
OS << 'G';
if (Flags & ELF::SHF_WRITE)
OS << 'w';
if (Flags & ELF::SHF_MERGE)
OS << 'M';
if (Flags & ELF::SHF_STRINGS)
OS << 'S';
if (Flags & ELF::SHF_TLS)
OS << 'T';
// If there are target-specific flags, print them.
if (Flags & ELF::XCORE_SHF_CP_SECTION)
OS << 'c';
if (Flags & ELF::XCORE_SHF_DP_SECTION)
OS << 'd';
OS << '"';
OS << ',';
// If comment string is '@', e.g. as on ARM - use '%' instead
if (MAI.getCommentString()[0] == '@')
OS << '%';
else
OS << '@';
if (Type == ELF::SHT_INIT_ARRAY)
OS << "init_array";
else if (Type == ELF::SHT_FINI_ARRAY)
OS << "fini_array";
else if (Type == ELF::SHT_PREINIT_ARRAY)
OS << "preinit_array";
else if (Type == ELF::SHT_NOBITS)
OS << "nobits";
else if (Type == ELF::SHT_NOTE)
OS << "note";
else if (Type == ELF::SHT_PROGBITS)
OS << "progbits";
if (EntrySize) {
assert(Flags & ELF::SHF_MERGE);
OS << "," << EntrySize;
}
if (Flags & ELF::SHF_GROUP) {
OS << ",";
printName(OS, Group->getName());
OS << ",comdat";
}
if (Unique)
OS << ",unique";
OS << '\n';
if (Subsection)
OS << "\t.subsection\t" << *Subsection << '\n';
}
bool MCSectionELF::UseCodeAlign() const {
return getFlags() & ELF::SHF_EXECINSTR;
}
bool MCSectionELF::isVirtualSection() const {
return getType() == ELF::SHT_NOBITS;
}