[tablegen] Extract portions of AsmMatcherEmitter for re-use by another generator. NFC.
Summary:
This change is preparation for a change that will allow targets to verify that the instructions
they emit meet the predicates they specify. This is useful to ensure that C++
legalization/lowering/instruction-selection doesn't incorrectly select code for a different
subtarget than intended. Such cases are not caught by the integrated assembler when emitting
instructions directly to an object file.
Reviewers: qcolombet
Subscribers: qcolombet, beanz, mgorny, llvm-commits, modocache
Differential Revision: https://reviews.llvm.org/D25614
llvm-svn: 286945
diff --git a/llvm/utils/TableGen/SubtargetFeatureInfo.cpp b/llvm/utils/TableGen/SubtargetFeatureInfo.cpp
new file mode 100644
index 0000000..2f9e881
--- /dev/null
+++ b/llvm/utils/TableGen/SubtargetFeatureInfo.cpp
@@ -0,0 +1,89 @@
+//===- SubtargetFeatureInfo.cpp - Helpers for subtarget features ----------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "SubtargetFeatureInfo.h"
+
+#include "llvm/TableGen/Record.h"
+
+#include <map>
+
+using namespace llvm;
+
+void SubtargetFeatureInfo::dump() const {
+ errs() << getEnumName() << " " << Index << "\n";
+ TheDef->dump();
+}
+
+std::vector<std::pair<Record *, SubtargetFeatureInfo>>
+SubtargetFeatureInfo::getAll(const RecordKeeper &Records) {
+ std::vector<std::pair<Record *, SubtargetFeatureInfo>> SubtargetFeatures;
+ std::vector<Record *> AllPredicates =
+ Records.getAllDerivedDefinitions("Predicate");
+ for (Record *Pred : AllPredicates) {
+ // Ignore predicates that are not intended for the assembler.
+ //
+ // The "AssemblerMatcherPredicate" string should be promoted to an argument
+ // if we re-use the machinery for non-assembler purposes in future.
+ if (!Pred->getValueAsBit("AssemblerMatcherPredicate"))
+ continue;
+
+ if (Pred->getName().empty())
+ PrintFatalError(Pred->getLoc(), "Predicate has no name!");
+
+ SubtargetFeatures.emplace_back(
+ Pred, SubtargetFeatureInfo(Pred, SubtargetFeatures.size()));
+ }
+ return SubtargetFeatures;
+}
+
+void SubtargetFeatureInfo::emitComputeAvailableFeatures(
+ StringRef TargetName, StringRef ClassName,
+ std::map<Record *, SubtargetFeatureInfo, LessRecordByID> &SubtargetFeatures,
+ raw_ostream &OS) {
+ OS << "uint64_t " << TargetName << ClassName << "::\n"
+ << "ComputeAvailableFeatures(const FeatureBitset& FB) const {\n";
+ OS << " uint64_t Features = 0;\n";
+ for (const auto &SF : SubtargetFeatures) {
+ const SubtargetFeatureInfo &SFI = SF.second;
+
+ OS << " if (";
+ std::string CondStorage =
+ SFI.TheDef->getValueAsString("AssemblerCondString");
+ StringRef Conds = CondStorage;
+ std::pair<StringRef, StringRef> Comma = Conds.split(',');
+ bool First = true;
+ do {
+ if (!First)
+ OS << " && ";
+
+ bool Neg = false;
+ StringRef Cond = Comma.first;
+ if (Cond[0] == '!') {
+ Neg = true;
+ Cond = Cond.substr(1);
+ }
+
+ OS << "(";
+ if (Neg)
+ OS << "!";
+ OS << "FB[" << TargetName << "::" << Cond << "])";
+
+ if (Comma.second.empty())
+ break;
+
+ First = false;
+ Comma = Comma.second.split(',');
+ } while (true);
+
+ OS << ")\n";
+ OS << " Features |= " << SFI.getEnumName() << ";\n";
+ }
+ OS << " return Features;\n";
+ OS << "}\n\n";
+}