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Add support for expressions in .sleb/.uleb directives.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118023 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Rafael Espindola
2010-11-02 17:22:24 +00:00
parent 8bc9ef77b7
commit 3ff57094a7
12 changed files with 236 additions and 95 deletions
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133
lib/MC/MCAssembler.cpp
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@ -318,6 +318,9 @@ uint64_t MCAssembler::ComputeFragmentSize(MCAsmLayout &Layout,
case MCFragment::FT_Inst:
return cast<MCInstFragment>(F).getInstSize();
case MCFragment::FT_LEB:
return cast<MCLEBFragment>(F).getSize();
case MCFragment::FT_Align: {
const MCAlignFragment &AF = cast<MCAlignFragment>(F);
@ -514,6 +517,23 @@ static void WriteFragmentData(const MCAssembler &Asm, const MCAsmLayout &Layout,
llvm_unreachable("unexpected inst fragment after lowering");
break;
case MCFragment::FT_LEB: {
MCLEBFragment &LF = cast<MCLEBFragment>(F);
// FIXME: It is probably better if we don't call EvaluateAsAbsolute in
// here.
int64_t Value;
LF.getValue().EvaluateAsAbsolute(Value, &Layout);
SmallString<32> Tmp;
raw_svector_ostream OSE(Tmp);
if (LF.isSigned())
MCObjectWriter::EncodeSLEB128(Value, OSE);
else
MCObjectWriter::EncodeULEB128(Value, OSE);
OW->WriteBytes(OSE.str());
break;
}
case MCFragment::FT_Org: {
MCOrgFragment &OF = cast<MCOrgFragment>(F);
@ -781,6 +801,63 @@ bool MCAssembler::FragmentNeedsRelaxation(const MCObjectWriter &Writer,
return false;
}
bool MCAssembler::RelaxInstruction(const MCObjectWriter &Writer,
MCAsmLayout &Layout,
MCInstFragment &IF) {
if (!FragmentNeedsRelaxation(Writer, &IF, Layout))
return false;
++stats::RelaxedInstructions;
// FIXME-PERF: We could immediately lower out instructions if we can tell
// they are fully resolved, to avoid retesting on later passes.
// Relax the fragment.
MCInst Relaxed;
getBackend().RelaxInstruction(IF.getInst(), Relaxed);
// Encode the new instruction.
//
// FIXME-PERF: If it matters, we could let the target do this. It can
// probably do so more efficiently in many cases.
SmallVector<MCFixup, 4> Fixups;
SmallString<256> Code;
raw_svector_ostream VecOS(Code);
getEmitter().EncodeInstruction(Relaxed, VecOS, Fixups);
VecOS.flush();
// Update the instruction fragment.
int SlideAmount = Code.size() - IF.getInstSize();
IF.setInst(Relaxed);
IF.getCode() = Code;
IF.getFixups().clear();
// FIXME: Eliminate copy.
for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
IF.getFixups().push_back(Fixups[i]);
// Update the layout, and remember that we relaxed.
Layout.UpdateForSlide(&IF, SlideAmount);
return true;
}
bool MCAssembler::RelaxLEB(const MCObjectWriter &Writer,
MCAsmLayout &Layout,
MCLEBFragment &LF) {
int64_t Value;
LF.getValue().EvaluateAsAbsolute(Value, &Layout);
SmallString<32> Tmp;
raw_svector_ostream OSE(Tmp);
if (LF.isSigned())
MCObjectWriter::EncodeSLEB128(Value, OSE);
else
MCObjectWriter::EncodeULEB128(Value, OSE);
uint64_t OldSize = LF.getSize();
LF.setSize(OSE.GetNumBytesInBuffer());
return OldSize != LF.getSize();
}
bool MCAssembler::LayoutOnce(const MCObjectWriter &Writer,
MCAsmLayout &Layout) {
++stats::RelaxationSteps;
@ -795,43 +872,18 @@ bool MCAssembler::LayoutOnce(const MCObjectWriter &Writer,
for (MCSectionData::iterator it2 = SD.begin(),
ie2 = SD.end(); it2 != ie2; ++it2) {
// Check if this is an instruction fragment that needs relaxation.
MCInstFragment *IF = dyn_cast<MCInstFragment>(it2);
if (!IF || !FragmentNeedsRelaxation(Writer, IF, Layout))
continue;
++stats::RelaxedInstructions;
// FIXME-PERF: We could immediately lower out instructions if we can tell
// they are fully resolved, to avoid retesting on later passes.
// Relax the fragment.
MCInst Relaxed;
getBackend().RelaxInstruction(IF->getInst(), Relaxed);
// Encode the new instruction.
//
// FIXME-PERF: If it matters, we could let the target do this. It can
// probably do so more efficiently in many cases.
SmallVector<MCFixup, 4> Fixups;
SmallString<256> Code;
raw_svector_ostream VecOS(Code);
getEmitter().EncodeInstruction(Relaxed, VecOS, Fixups);
VecOS.flush();
// Update the instruction fragment.
int SlideAmount = Code.size() - IF->getInstSize();
IF->setInst(Relaxed);
IF->getCode() = Code;
IF->getFixups().clear();
// FIXME: Eliminate copy.
for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
IF->getFixups().push_back(Fixups[i]);
// Update the layout, and remember that we relaxed.
Layout.UpdateForSlide(IF, SlideAmount);
WasRelaxed = true;
// Check if this is an fragment that needs relaxation.
switch(it2->getKind()) {
default:
break;
case MCFragment::FT_Inst:
WasRelaxed |= RelaxInstruction(Writer, Layout,
*cast<MCInstFragment>(it2));
break;
case MCFragment::FT_LEB:
WasRelaxed |= RelaxLEB(Writer, Layout, *cast<MCLEBFragment>(it2));
break;
}
}
}
@ -903,6 +955,7 @@ void MCFragment::dump() {
case MCFragment::FT_Inst: OS << "MCInstFragment"; break;
case MCFragment::FT_Org: OS << "MCOrgFragment"; break;
case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
case MCFragment::FT_LEB: OS << "MCLEBFragment"; break;
}
OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
@ -970,6 +1023,12 @@ void MCFragment::dump() {
<< " LineDelta:" << OF->getLineDelta();
break;
}
case MCFragment::FT_LEB: {
const MCLEBFragment *LF = cast<MCLEBFragment>(this);
OS << "\n ";
OS << " Value:" << LF->getValue() << " Signed:" << LF->isSigned();
break;
}
}
OS << ">";
}