MCELF: Port EmitInstruction changes from MachO streamer. Patch by Roman Divacky.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112260 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index 2631c5f..fcc6262 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -34,6 +34,8 @@
namespace {
class MCELFStreamer : public MCObjectStreamer {
+ void EmitInstToFragment(const MCInst &Inst);
+ void EmitInstToData(const MCInst &Inst);
public:
MCELFStreamer(MCContext &Context, TargetAsmBackend &TAB,
raw_ostream &OS, MCCodeEmitter *Emitter)
@@ -328,6 +330,40 @@
SD.setFlags(ELF_STT_File | ELF_STB_Local | ELF_STV_Default);
}
+void MCELFStreamer::EmitInstToFragment(const MCInst &Inst) {
+ MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
+
+ // Add the fixups and data.
+ //
+ // FIXME: Revisit this design decision when relaxation is done, we may be
+ // able to get away with not storing any extra data in the MCInst.
+ SmallVector<MCFixup, 4> Fixups;
+ SmallString<256> Code;
+ raw_svector_ostream VecOS(Code);
+ getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
+ VecOS.flush();
+
+ IF->getCode() = Code;
+ IF->getFixups() = Fixups;
+}
+
+void MCELFStreamer::EmitInstToData(const MCInst &Inst) {
+ MCDataFragment *DF = getOrCreateDataFragment();
+
+ SmallVector<MCFixup, 4> Fixups;
+ SmallString<256> Code;
+ raw_svector_ostream VecOS(Code);
+ getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
+ VecOS.flush();
+
+ // Add the fixups and data.
+ for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
+ Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
+ DF->addFixup(Fixups[i]);
+ }
+ DF->getContents().append(Code.begin(), Code.end());
+}
+
void MCELFStreamer::EmitInstruction(const MCInst &Inst) {
// Scan for values.
for (unsigned i = 0; i != Inst.getNumOperands(); ++i)
@@ -336,56 +372,25 @@
getCurrentSectionData()->setHasInstructions(true);
- // FIXME-PERF: Common case is that we don't need to relax, encode directly
- // onto the data fragments buffers.
-
- SmallVector<MCFixup, 4> Fixups;
- SmallString<256> Code;
- raw_svector_ostream VecOS(Code);
- getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
- VecOS.flush();
-
- // FIXME: Eliminate this copy.
- SmallVector<MCFixup, 4> AsmFixups;
- for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
- MCFixup &F = Fixups[i];
- AsmFixups.push_back(MCFixup::Create(F.getOffset(), F.getValue(),
- F.getKind()));
- }
-
- // See if we might need to relax this instruction, if so it needs its own
- // fragment.
- //
- // FIXME-PERF: Support target hook to do a fast path that avoids the encoder,
- // when we can immediately tell that we will get something which might need
- // relaxation (and compute its size).
- //
- // FIXME-PERF: We should also be smart about immediately relaxing instructions
- // which we can already show will never possibly fit (we can also do a very
- // good job of this before we do the first relaxation pass, because we have
- // 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 (getAssembler().getBackend().MayNeedRelaxation(Inst)) {
- MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData());
-
- // Add the fixups and data.
- //
- // FIXME: Revisit this design decision when relaxation is done, we may be
- // able to get away with not storing any extra data in the MCInst.
- IF->getCode() = Code;
- IF->getFixups() = AsmFixups;
-
+ // If this instruction doesn't need relaxation, just emit it as data.
+ if (!getAssembler().getBackend().MayNeedRelaxation(Inst)) {
+ EmitInstToData(Inst);
return;
}
- // Add the fixups and data.
- MCDataFragment *DF = getOrCreateDataFragment();
- for (unsigned i = 0, e = AsmFixups.size(); i != e; ++i) {
- AsmFixups[i].setOffset(AsmFixups[i].getOffset() + DF->getContents().size());
- DF->addFixup(AsmFixups[i]);
+ // Otherwise, if we are relaxing everything, relax the instruction as much as
+ // possible and emit it as data.
+ if (getAssembler().getRelaxAll()) {
+ MCInst Relaxed;
+ getAssembler().getBackend().RelaxInstruction(Inst, Relaxed);
+ while (getAssembler().getBackend().MayNeedRelaxation(Relaxed))
+ getAssembler().getBackend().RelaxInstruction(Relaxed, Relaxed);
+ EmitInstToData(Relaxed);
+ return;
}
- DF->getContents().append(Code.begin(), Code.end());
+
+ // Otherwise emit to a separate fragment.
+ EmitInstToFragment(Inst);
}
void MCELFStreamer::Finish() {