RuntimeLibcalls: Add methods to recognize libcall names (#149001)

Also replace the current static DenseMap of preserved symbol
names in the Symtab hack with this. That was broken statefulness
across compiles, so this at least fixes that. However this is
still broken, llvm-as shouldn't really depend on the triple.

1 files changed, 22 insertions, 23 deletions

diff --git a/llvm/lib/Object/IRSymtab.cpp b/llvm/lib/Object/IRSymtab.cpp
index 2579fa3..79eeb08 100644
--- a/llvm/lib/Object/IRSymtab.cpp
+++ b/llvm/lib/Object/IRSymtab.cpp
@@ -54,6 +54,11 @@ static const char *PreservedSymbols[] = {
     "__stack_chk_guard",
 };
 
+static bool isPreservedGlobalVarName(StringRef Name) {
+  return StringRef(PreservedSymbols[0]) == Name ||
+         StringRef(PreservedSymbols[1]) == Name;
+}
+
 namespace {
 
 const char *getExpectedProducerName() {
@@ -81,12 +86,16 @@ struct Builder {
   // The StringTableBuilder does not create a copy of any strings added to it,
   // so this provides somewhere to store any strings that we create.
   Builder(SmallVector<char, 0> &Symtab, StringTableBuilder &StrtabBuilder,
-          BumpPtrAllocator &Alloc)
-      : Symtab(Symtab), StrtabBuilder(StrtabBuilder), Saver(Alloc) {}
+          BumpPtrAllocator &Alloc, const Triple &TT)
+      : Symtab(Symtab), StrtabBuilder(StrtabBuilder), Saver(Alloc), TT(TT),
+        Libcalls(TT) {}
 
   DenseMap<const Comdat *, int> ComdatMap;
   Mangler Mang;
-  Triple TT;
+  const Triple &TT;
+
+  // FIXME: This shouldn't be here.
+  RTLIB::RuntimeLibcallsInfo Libcalls;
 
   std::vector<storage::Comdat> Comdats;
   std::vector<storage::Module> Mods;
@@ -98,6 +107,10 @@ struct Builder {
 
   std::vector<storage::Str> DependentLibraries;
 
+  bool isPreservedLibFuncName(StringRef Name) {
+    return Libcalls.getSupportedLibcallImpl(Name) != RTLIB::Unsupported;
+  }
+
   void setStr(storage::Str &S, StringRef Value) {
     S.Offset = StrtabBuilder.add(Value);
     S.Size = Value.size();
@@ -213,18 +226,6 @@ Expected<int> Builder::getComdatIndex(const Comdat *C, const Module *M) {
   return P.first->second;
 }
 
-static DenseSet<StringRef> buildPreservedSymbolsSet(const Triple &TT) {
-  DenseSet<StringRef> PreservedSymbolSet(std::begin(PreservedSymbols),
-                                         std::end(PreservedSymbols));
-  // FIXME: Do we need to pass in ABI fields from TargetOptions?
-  RTLIB::RuntimeLibcallsInfo Libcalls(TT);
-  for (RTLIB::LibcallImpl Impl : Libcalls.getLibcallImpls()) {
-    if (Impl != RTLIB::Unsupported)
-      PreservedSymbolSet.insert(Libcalls.getLibcallImplName(Impl));
-  }
-  return PreservedSymbolSet;
-}
-
 Error Builder::addSymbol(const ModuleSymbolTable &Msymtab,
                          const SmallPtrSet<GlobalValue *, 4> &Used,
                          ModuleSymbolTable::Symbol Msym) {
@@ -278,13 +279,11 @@ Error Builder::addSymbol(const ModuleSymbolTable &Msymtab,
     return Error::success();
   }
 
-  setStr(Sym.IRName, GV->getName());
-
-  static const DenseSet<StringRef> PreservedSymbolsSet =
-      buildPreservedSymbolsSet(GV->getParent()->getTargetTriple());
-  bool IsPreservedSymbol = PreservedSymbolsSet.contains(GV->getName());
+  StringRef GVName = GV->getName();
+  setStr(Sym.IRName, GVName);
 
-  if (Used.count(GV) || IsPreservedSymbol)
+  if (Used.count(GV) || isPreservedLibFuncName(GVName) ||
+      isPreservedGlobalVarName(GVName))
     Sym.Flags |= 1 << storage::Symbol::FB_used;
   if (GV->isThreadLocal())
     Sym.Flags |= 1 << storage::Symbol::FB_tls;
@@ -351,7 +350,6 @@ Error Builder::build(ArrayRef<Module *> IRMods) {
   setStr(Hdr.Producer, kExpectedProducerName);
   setStr(Hdr.TargetTriple, IRMods[0]->getTargetTriple().str());
   setStr(Hdr.SourceFileName, IRMods[0]->getSourceFileName());
-  TT = IRMods[0]->getTargetTriple();
 
   for (auto *M : IRMods)
     if (Error Err = addModule(M))
@@ -377,7 +375,8 @@ Error Builder::build(ArrayRef<Module *> IRMods) {
 Error irsymtab::build(ArrayRef<Module *> Mods, SmallVector<char, 0> &Symtab,
                       StringTableBuilder &StrtabBuilder,
                       BumpPtrAllocator &Alloc) {
-  return Builder(Symtab, StrtabBuilder, Alloc).build(Mods);
+  const Triple &TT = Mods[0]->getTargetTriple();
+  return Builder(Symtab, StrtabBuilder, Alloc, TT).build(Mods);
 }
 
 // Upgrade a vector of bitcode modules created by an old version of LLVM by