[llvm] [llvm-profgen] Loading binary functions from .symtab when DWARF info is incomplete (PR #163654)

[via llvm-commits]

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@@ -820,6 +830,54 @@ void ProfiledBinary::populateSymbolAddressList(const ObjectFile *Obj) {
   }
 }
 
+void ProfiledBinary::populateSymbolsFromBinary(const ObjectFile *Obj) {
+  // Load binary functions from symbol table when Debug info is incomplete
+  const SmallVector<StringRef> Suffixes(
+      {".destroy", ".resume", ".llvm.", ".cold", ".warm"});
+  StringRef FileName = Obj->getFileName();
+  for (const SymbolRef &Symbol : Obj->symbols()) {
+    const SymbolRef::Type Type = unwrapOrError(Symbol.getType(), FileName);
+    const uint64_t Addr = unwrapOrError(Symbol.getAddress(), FileName);
+    const StringRef Name = unwrapOrError(Symbol.getName(), FileName);
+    uint64_t Size = 0;
+    if (isa<ELFObjectFileBase>(Symbol.getObject())) {
+      ELFSymbolRef ElfSymbol(Symbol);
+      Size = ElfSymbol.getSize();
+    }
+
+    if (Size == 0 || Type != SymbolRef::ST_Function)
+      continue;
+
+    const StringRef SymName =
+        FunctionSamples::getCanonicalFnName(Name, Suffixes);
+
+    auto Ret = BinaryFunctions.emplace(SymName, BinaryFunction());
+    auto &Func = Ret.first->second;
+    if (Ret.second) {
+      Func.FuncName = Ret.first->first;
+      HashBinaryFunctions[MD5Hash(StringRef(SymName))] = &Func;
+    }
+
+    if (auto Range = findFuncRange(Addr)) {
+      if (Ret.second && ShowDetailedWarning)
+        WithColor::warning()
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WenleiHe wrote:

Symbol table finding entry already existing in dwarf should not be a warning. 

When that happens, we should check if they both point to same ranges, and only warn when 
1) symbol table and dwarf conflicts for the actual range.
2) something is in symbol table, but not in dwarf (suggesting dwarf corrupted, e.g. due to relo overflow) 

https://github.com/llvm/llvm-project/pull/163654