Use std::bitset for SubtargetFeatures.
Previously, subtarget features were a bitfield with the underlying type being uint64_t.
Since several targets (X86 and ARM, in particular) have hit or were very close to hitting this bound, switching the features to use a bitset.
No functional change.
The first several times this was committed (e.g. r229831, r233055), it caused several buildbot failures.
Apparently the reason for most failures was both clang and gcc's inability to deal with large numbers (> 10K) of bitset constructor calls in tablegen-generated initializers of instruction info tables.
This should now be fixed.
llvm-svn: 238192
diff --git a/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp b/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
index 772294c..3469d19 100644
--- a/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
+++ b/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
@@ -80,20 +80,19 @@
MCContext &Ctx,
std::unique_ptr<const MCInstrInfo> MII)
: MCDisassembler(STI, Ctx), MII(std::move(MII)) {
- switch (STI.getFeatureBits() &
- (X86::Mode16Bit | X86::Mode32Bit | X86::Mode64Bit)) {
- case X86::Mode16Bit:
+ const FeatureBitset &FB = STI.getFeatureBits();
+ if (FB[X86::Mode16Bit]) {
fMode = MODE_16BIT;
- break;
- case X86::Mode32Bit:
+ return;
+ } else if (FB[X86::Mode32Bit]) {
fMode = MODE_32BIT;
- break;
- case X86::Mode64Bit:
+ return;
+ } else if (FB[X86::Mode64Bit]) {
fMode = MODE_64BIT;
- break;
- default:
- llvm_unreachable("Invalid CPU mode");
+ return;
}
+
+ llvm_unreachable("Invalid CPU mode");
}
struct Region {