From 044eb2f6afba375a914ac9d8024f8f5142bb912e Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Mon, 18 Dec 2017 20:10:56 +0000
Subject: Vendor import of llvm trunk r321017:
 https://llvm.org/svn/llvm-project/llvm/trunk@321017

---
 lib/Object/IRSymtab.cpp | 58 +++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 46 insertions(+), 12 deletions(-)

(limited to 'lib/Object/IRSymtab.cpp')

diff --git a/lib/Object/IRSymtab.cpp b/lib/Object/IRSymtab.cpp
index 7a6424a76a981..2d8d3f7c08780 100644
--- a/lib/Object/IRSymtab.cpp
+++ b/lib/Object/IRSymtab.cpp
@@ -72,7 +72,7 @@ struct Builder {
           BumpPtrAllocator &Alloc)
       : Symtab(Symtab), StrtabBuilder(StrtabBuilder), Saver(Alloc) {}
 
-  DenseMap<const Comdat *, unsigned> ComdatMap;
+  DenseMap<const Comdat *, int> ComdatMap;
   Mangler Mang;
   Triple TT;
 
@@ -97,6 +97,8 @@ struct Builder {
                   reinterpret_cast<const char *>(Objs.data() + Objs.size()));
   }
 
+  Expected<int> getComdatIndex(const Comdat *C, const Module *M);
+
   Error addModule(Module *M);
   Error addSymbol(const ModuleSymbolTable &Msymtab,
                   const SmallPtrSet<GlobalValue *, 8> &Used,
@@ -140,6 +142,35 @@ Error Builder::addModule(Module *M) {
   return Error::success();
 }
 
+Expected<int> Builder::getComdatIndex(const Comdat *C, const Module *M) {
+  auto P = ComdatMap.insert(std::make_pair(C, Comdats.size()));
+  if (P.second) {
+    std::string Name;
+    if (TT.isOSBinFormatCOFF()) {
+      const GlobalValue *GV = M->getNamedValue(C->getName());
+      if (!GV)
+        return make_error<StringError>("Could not find leader",
+                                       inconvertibleErrorCode());
+      // Internal leaders do not affect symbol resolution, therefore they do not
+      // appear in the symbol table.
+      if (GV->hasLocalLinkage()) {
+        P.first->second = -1;
+        return -1;
+      }
+      llvm::raw_string_ostream OS(Name);
+      Mang.getNameWithPrefix(OS, GV, false);
+    } else {
+      Name = C->getName();
+    }
+
+    storage::Comdat Comdat;
+    setStr(Comdat.Name, Saver.save(Name));
+    Comdats.push_back(Comdat);
+  }
+
+  return P.first->second;
+}
+
 Error Builder::addSymbol(const ModuleSymbolTable &Msymtab,
                          const SmallPtrSet<GlobalValue *, 8> &Used,
                          ModuleSymbolTable::Symbol Msym) {
@@ -156,6 +187,7 @@ Error Builder::addSymbol(const ModuleSymbolTable &Msymtab,
     Unc = &Uncommons.back();
     *Unc = {};
     setStr(Unc->COFFWeakExternFallbackName, "");
+    setStr(Unc->SectionName, "");
     return *Unc;
   };
 
@@ -215,14 +247,10 @@ Error Builder::addSymbol(const ModuleSymbolTable &Msymtab,
     return make_error<StringError>("Unable to determine comdat of alias!",
                                    inconvertibleErrorCode());
   if (const Comdat *C = Base->getComdat()) {
-    auto P = ComdatMap.insert(std::make_pair(C, Comdats.size()));
-    Sym.ComdatIndex = P.first->second;
-
-    if (P.second) {
-      storage::Comdat Comdat;
-      setStr(Comdat.Name, C->getName());
-      Comdats.push_back(Comdat);
-    }
+    Expected<int> ComdatIndexOrErr = getComdatIndex(C, GV->getParent());
+    if (!ComdatIndexOrErr)
+      return ComdatIndexOrErr.takeError();
+    Sym.ComdatIndex = *ComdatIndexOrErr;
   }
 
   if (TT.isOSBinFormatCOFF()) {
@@ -230,16 +258,22 @@ Error Builder::addSymbol(const ModuleSymbolTable &Msymtab,
 
     if ((Flags & object::BasicSymbolRef::SF_Weak) &&
         (Flags & object::BasicSymbolRef::SF_Indirect)) {
+      auto *Fallback = dyn_cast<GlobalValue>(
+          cast<GlobalAlias>(GV)->getAliasee()->stripPointerCasts());
+      if (!Fallback)
+        return make_error<StringError>("Invalid weak external",
+                                       inconvertibleErrorCode());
       std::string FallbackName;
       raw_string_ostream OS(FallbackName);
-      Msymtab.printSymbolName(
-          OS, cast<GlobalValue>(
-                  cast<GlobalAlias>(GV)->getAliasee()->stripPointerCasts()));
+      Msymtab.printSymbolName(OS, Fallback);
       OS.flush();
       setStr(Uncommon().COFFWeakExternFallbackName, Saver.save(FallbackName));
     }
   }
 
+  if (!Base->getSection().empty())
+    setStr(Uncommon().SectionName, Saver.save(Base->getSection()));
+
   return Error::success();
 }
 
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