Jack Carter f9f753c2ea Mips ELF: Mark object file as ABI compliant
When producing objects that are abi compliant we are 
marking neither the object file nor the assembly file
correctly and thus generate warnings. 

We need to set the EF_CPIC flag in the ELF header when
generating direct object.

Note that the warning is only generated when compiling without PIC.

When compiling with clang the warning will be suppressed by supplying:

 -Wa,-mno-shared -Wa,-call_nonpic

Also the following directive should also be added:

	.option	pic0

when compiling without PIC,  This eliminates the need for supplying:

  -mno-shared -call_nonpic

on the assembler command line.

Patch by Douglas Gilmore

llvm-svn: 184220
2013-06-18 19:47:15 +00:00

94 lines
2.9 KiB
C++

//===-- MipsELFStreamer.cpp - MipsELFStreamer ---------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===-------------------------------------------------------------------===//
#include "MCTargetDesc/MipsELFStreamer.h"
#include "MipsSubtarget.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCELF.h"
#include "llvm/MC/MCELFSymbolFlags.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
namespace llvm {
MCELFStreamer* createMipsELFStreamer(MCContext &Context, MCAsmBackend &TAB,
raw_ostream &OS, MCCodeEmitter *Emitter,
bool RelaxAll, bool NoExecStack) {
MipsELFStreamer *S = new MipsELFStreamer(Context, TAB, OS, Emitter,
RelaxAll, NoExecStack);
return S;
}
// For llc. Set a group of ELF header flags
void
MipsELFStreamer::emitELFHeaderFlagsCG(const MipsSubtarget &Subtarget) {
if (hasRawTextSupport())
return;
// Update e_header flags
MCAssembler& MCA = getAssembler();
unsigned EFlags = MCA.getELFHeaderEFlags();
// TODO: Need to add -mabicalls and -mno-abicalls flags.
// Currently we assume that -mabicalls is the default.
EFlags |= ELF::EF_MIPS_CPIC;
if (Subtarget.inMips16Mode())
EFlags |= ELF::EF_MIPS_ARCH_ASE_M16;
else
EFlags |= ELF::EF_MIPS_NOREORDER;
// Architecture
if (Subtarget.hasMips64r2())
EFlags |= ELF::EF_MIPS_ARCH_64R2;
else if (Subtarget.hasMips64())
EFlags |= ELF::EF_MIPS_ARCH_64;
else if (Subtarget.hasMips32r2())
EFlags |= ELF::EF_MIPS_ARCH_32R2;
else
EFlags |= ELF::EF_MIPS_ARCH_32;
if (Subtarget.inMicroMipsMode())
EFlags |= ELF::EF_MIPS_MICROMIPS;
// ABI
if (Subtarget.isABI_O32())
EFlags |= ELF::EF_MIPS_ABI_O32;
// Relocation Model
Reloc::Model RM = Subtarget.getRelocationModel();
if (RM == Reloc::PIC_ || RM == Reloc::Default)
EFlags |= ELF::EF_MIPS_PIC;
else if (RM == Reloc::Static)
; // Do nothing for Reloc::Static
else
llvm_unreachable("Unsupported relocation model for e_flags");
MCA.setELFHeaderEFlags(EFlags);
}
// For llc. Set a symbol's STO flags
void
MipsELFStreamer::emitMipsSTOCG(const MipsSubtarget &Subtarget,
MCSymbol *Sym,
unsigned Val) {
if (hasRawTextSupport())
return;
MCSymbolData &Data = getOrCreateSymbolData(Sym);
// The "other" values are stored in the last 6 bits of the second byte
// The traditional defines for STO values assume the full byte and thus
// the shift to pack it.
MCELF::setOther(Data, Val >> 2);
}
} // namespace llvm