llvm-6502/lib/MC/MCSubtargetInfo.cpp
Duncan P. N. Exon Smith c9978bab4b MC: Only allow changing feature bits in MCSubtargetInfo
Disallow all mutation of `MCSubtargetInfo` expect the feature bits.

Besides deleting the assignment operators -- which were dead "code" --
this restricts `InitMCProcessorInfo()` to subclass initialization
sequences, and exposes a new more limited function called
`setDefaultFeatures()` for use by the ARMAsmParser `.cpu` directive.

There's a small functional change here: ARMAsmParser used to adjust
`MCSubtargetInfo::CPUSchedModel` as a side effect of calling
`InitMCProcessorInfo()`, but I've removed that suspicious behaviour.
Since the AsmParser shouldn't be doing any scheduling, there shouldn't
be any observable change...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241961 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-10 22:52:15 +00:00

113 lines
4.1 KiB
C++

//===-- MCSubtargetInfo.cpp - Subtarget Information -----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/MC/MCInstrItineraries.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace llvm;
static FeatureBitset getFeatures(StringRef CPU, StringRef FS,
ArrayRef<SubtargetFeatureKV> ProcDesc,
ArrayRef<SubtargetFeatureKV> ProcFeatures) {
SubtargetFeatures Features(FS);
return Features.getFeatureBits(CPU, ProcDesc, ProcFeatures);
}
void MCSubtargetInfo::InitMCProcessorInfo(StringRef CPU, StringRef FS) {
FeatureBits = getFeatures(CPU, FS, ProcDesc, ProcFeatures);
if (!CPU.empty())
CPUSchedModel = &getSchedModelForCPU(CPU);
else
CPUSchedModel = &MCSchedModel::GetDefaultSchedModel();
}
void MCSubtargetInfo::setDefaultFeatures(StringRef CPU) {
FeatureBits = getFeatures(CPU, "", ProcDesc, ProcFeatures);
}
MCSubtargetInfo::MCSubtargetInfo(
const Triple &TT, StringRef C, StringRef FS,
ArrayRef<SubtargetFeatureKV> PF, ArrayRef<SubtargetFeatureKV> PD,
const SubtargetInfoKV *ProcSched, const MCWriteProcResEntry *WPR,
const MCWriteLatencyEntry *WL, const MCReadAdvanceEntry *RA,
const InstrStage *IS, const unsigned *OC, const unsigned *FP)
: TargetTriple(TT), CPU(C), ProcFeatures(PF), ProcDesc(PD),
ProcSchedModels(ProcSched), WriteProcResTable(WPR), WriteLatencyTable(WL),
ReadAdvanceTable(RA), Stages(IS), OperandCycles(OC), ForwardingPaths(FP) {
InitMCProcessorInfo(CPU, FS);
}
/// ToggleFeature - Toggle a feature and returns the re-computed feature
/// bits. This version does not change the implied bits.
FeatureBitset MCSubtargetInfo::ToggleFeature(uint64_t FB) {
FeatureBits.flip(FB);
return FeatureBits;
}
FeatureBitset MCSubtargetInfo::ToggleFeature(const FeatureBitset &FB) {
FeatureBits ^= FB;
return FeatureBits;
}
/// ToggleFeature - Toggle a feature and returns the re-computed feature
/// bits. This version will also change all implied bits.
FeatureBitset MCSubtargetInfo::ToggleFeature(StringRef FS) {
SubtargetFeatures Features;
FeatureBits = Features.ToggleFeature(FeatureBits, FS, ProcFeatures);
return FeatureBits;
}
FeatureBitset MCSubtargetInfo::ApplyFeatureFlag(StringRef FS) {
SubtargetFeatures Features;
FeatureBits = Features.ApplyFeatureFlag(FeatureBits, FS, ProcFeatures);
return FeatureBits;
}
const MCSchedModel &MCSubtargetInfo::getSchedModelForCPU(StringRef CPU) const {
assert(ProcSchedModels && "Processor machine model not available!");
unsigned NumProcs = ProcDesc.size();
#ifndef NDEBUG
for (size_t i = 1; i < NumProcs; i++) {
assert(strcmp(ProcSchedModels[i - 1].Key, ProcSchedModels[i].Key) < 0 &&
"Processor machine model table is not sorted");
}
#endif
// Find entry
const SubtargetInfoKV *Found =
std::lower_bound(ProcSchedModels, ProcSchedModels+NumProcs, CPU);
if (Found == ProcSchedModels+NumProcs || StringRef(Found->Key) != CPU) {
if (CPU != "help") // Don't error if the user asked for help.
errs() << "'" << CPU
<< "' is not a recognized processor for this target"
<< " (ignoring processor)\n";
return MCSchedModel::GetDefaultSchedModel();
}
assert(Found->Value && "Missing processor SchedModel value");
return *(const MCSchedModel *)Found->Value;
}
InstrItineraryData
MCSubtargetInfo::getInstrItineraryForCPU(StringRef CPU) const {
const MCSchedModel SchedModel = getSchedModelForCPU(CPU);
return InstrItineraryData(SchedModel, Stages, OperandCycles, ForwardingPaths);
}
/// Initialize an InstrItineraryData instance.
void MCSubtargetInfo::initInstrItins(InstrItineraryData &InstrItins) const {
InstrItins = InstrItineraryData(getSchedModel(), Stages, OperandCycles,
ForwardingPaths);
}