Reduce the size of MCRelaxableFragment.
MCRelaxableFragment previously kept a copy of MCSubtargetInfo and
MCInst to enable re-encoding the MCInst later during relaxation. A copy
of MCSubtargetInfo (instead of a reference or pointer) was needed
because the feature bits could be modified by the parser.
This commit replaces the MCSubtargetInfo copy in MCRelaxableFragment
with a constant reference to MCSubtargetInfo. The copies of
MCSubtargetInfo are kept in MCContext, and the target parsers are now
responsible for asking MCContext to provide a copy whenever the feature
bits of MCSubtargetInfo have to be toggled.
With this patch, I saw a 4% reduction in peak memory usage when I
compiled verify-uselistorder.lto.bc using llc.
rdar://problem/21736951
Differential Revision: http://reviews.llvm.org/D14346
llvm-svn: 253127
diff --git a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
index 1794ede..0512ebc 100644
--- a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -346,6 +346,7 @@
// FeatureMipsGP64 | FeatureMips1)
// Clearing Mips3 is equivalent to clear (FeatureMips3 | FeatureMips4).
void selectArch(StringRef ArchFeature) {
+ MCSubtargetInfo &STI = copySTI();
FeatureBitset FeatureBits = STI.getFeatureBits();
FeatureBits &= ~MipsAssemblerOptions::AllArchRelatedMask;
STI.setFeatureBits(FeatureBits);
@@ -356,6 +357,7 @@
void setFeatureBits(uint64_t Feature, StringRef FeatureString) {
if (!(getSTI().getFeatureBits()[Feature])) {
+ MCSubtargetInfo &STI = copySTI();
setAvailableFeatures(
ComputeAvailableFeatures(STI.ToggleFeature(FeatureString)));
AssemblerOptions.back()->setFeatures(STI.getFeatureBits());
@@ -364,6 +366,7 @@
void clearFeatureBits(uint64_t Feature, StringRef FeatureString) {
if (getSTI().getFeatureBits()[Feature]) {
+ MCSubtargetInfo &STI = copySTI();
setAvailableFeatures(
ComputeAvailableFeatures(STI.ToggleFeature(FeatureString)));
AssemblerOptions.back()->setFeatures(STI.getFeatureBits());
@@ -388,7 +391,7 @@
#undef GET_OPERAND_DIAGNOSTIC_TYPES
};
- MipsAsmParser(MCSubtargetInfo &sti, MCAsmParser &parser,
+ MipsAsmParser(const MCSubtargetInfo &sti, MCAsmParser &parser,
const MCInstrInfo &MII, const MCTargetOptions &Options)
: MCTargetAsmParser(Options, sti),
ABI(MipsABIInfo::computeTargetABI(Triple(sti.getTargetTriple()),
@@ -4746,6 +4749,7 @@
if (AssemblerOptions.size() == 2)
return reportParseError(Loc, ".set pop with no .set push");
+ MCSubtargetInfo &STI = copySTI();
AssemblerOptions.pop_back();
setAvailableFeatures(
ComputeAvailableFeatures(AssemblerOptions.back()->getFeatures()));
@@ -4819,6 +4823,7 @@
return reportParseError("unexpected token, expected end of statement");
// Reset assembler options to their initial values.
+ MCSubtargetInfo &STI = copySTI();
setAvailableFeatures(
ComputeAvailableFeatures(AssemblerOptions.front()->getFeatures()));
STI.setFeatureBits(AssemblerOptions.front()->getFeatures());