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MC: Simplify MayNeedRelaxation to not provide the fixups, so we can query it

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llvm-svn: 104707
This commit is contained in:
Daniel Dunbar 2010-05-26 17:45:29 +00:00
parent 6f08a37562
commit 77240e2337
4 changed files with 13 additions and 32 deletions
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5
include/llvm/Target/TargetAsmBackend.h
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@ -112,10 +112,7 @@ public:
/// relaxation.
///
/// \arg Inst - The instruction to test.
/// \arg Fixups - The actual fixups this instruction encoded to, for potential
/// use by the target backend.
virtual bool MayNeedRelaxation(const MCInst &Inst,
const SmallVectorImpl<MCFixup> &Fixups) const = 0;
virtual bool MayNeedRelaxation(const MCInst &Inst) const = 0;
/// RelaxInstruction - Relax the instruction in the given fragment to the next
/// wider instruction.

2
lib/MC/MCAssembler.cpp
View File

@ -787,7 +787,7 @@ bool MCAssembler::FragmentNeedsRelaxation(const MCInstFragment *IF,
// If this inst doesn't ever need relaxation, ignore it. This occurs when we
// are intentionally pushing out inst fragments, or because we relaxed a
// previous instruction to one that doesn't need relaxation.
if (!getBackend().MayNeedRelaxation(IF->getInst(), IF->getFixups()))
if (!getBackend().MayNeedRelaxation(IF->getInst()))
return false;
for (MCInstFragment::const_fixup_iterator it = IF->fixup_begin(),

2
lib/MC/MCMachOStreamer.cpp
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@ -452,7 +452,7 @@ void MCMachOStreamer::EmitInstruction(const MCInst &Inst) {
// total knowledge about undefined symbols at that point). Even now, though,
// we can do a decent job, especially on Darwin where scattering means that we
// are going to often know that we can never fully resolve a fixup.
if (Assembler.getBackend().MayNeedRelaxation(Inst, AsmFixups)) {
if (Assembler.getBackend().MayNeedRelaxation(Inst)) {
MCInstFragment *IF = new MCInstFragment(Inst, CurSectionData);
IF->setAtom(CurrentAtomMap.lookup(CurSectionData));

36
lib/Target/X86/X86AsmBackend.cpp
View File

@ -54,8 +54,7 @@ public:
DF.getContents()[Fixup.getOffset() + i] = uint8_t(Value >> (i * 8));
}
bool MayNeedRelaxation(const MCInst &Inst,
const SmallVectorImpl<MCFixup> &Fixups) const;
bool MayNeedRelaxation(const MCInst &Inst) const;
void RelaxInstruction(const MCInstFragment *IF, MCInst &Res) const;
@ -88,31 +87,16 @@ static unsigned getRelaxedOpcode(unsigned Op) {
}
}
bool X86AsmBackend::MayNeedRelaxation(const MCInst &Inst,
const SmallVectorImpl<MCFixup> &Fixups) const {
for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
const MCFixup &F = Fixups[i];
bool X86AsmBackend::MayNeedRelaxation(const MCInst &Inst) const {
// Check if this instruction is ever relaxable.
if (getRelaxedOpcode(Inst.getOpcode()) == Inst.getOpcode())
return false;
// We don't support relaxing anything else currently. Make sure we error out
// if we see a non-constant 1 or 2 byte fixup.
//
// FIXME: We should need to check this here, this is better checked in the
// object writer which should be verifying that any final relocations match
// the expected fixup. However, that code is more complicated and hasn't
// been written yet. See the FIXMEs in MachObjectWriter.cpp.
if ((F.getKind() == FK_Data_1 || F.getKind() == FK_Data_2) &&
!isa<MCConstantExpr>(F.getValue()))
report_fatal_error("unexpected small fixup with a non-constant operand!");
// Check for a 1byte pcrel fixup, and enforce that we would know how to
// relax this instruction.
if (unsigned(F.getKind()) == X86::reloc_pcrel_1byte) {
assert(getRelaxedOpcode(Inst.getOpcode()) != Inst.getOpcode());
return true;
}
}
return false;
// If so, just assume it can be relaxed. Once we support relaxing more complex
// instructions we should check that the instruction actually has symbolic
// operands before doing this, but we need to be careful about things like
// PCrel.
return true;
}
// FIXME: Can tblgen help at all here to verify there aren't other instructions