From 5cb64b18b7f3f8222f7b4ea4c001f24cf4077ad3 Mon Sep 17 00:00:00 2001
From: Mehdi Amini <mehdi.amini@apple.com>
Date: Tue, 14 Feb 2017 02:20:51 +0000
Subject: [PATCH] [ThinLTO] Make a copy of buffer identifier in
 ThinLTOCodeGenerator

We can't assume that the `const char *` provided through libLTO has a
lifetime that expands beyond the codegenerator itself.

llvm-svn: 295018
---
 .../llvm/LTO/legacy/ThinLTOCodeGenerator.h    | 19 +++++++++++-
 lib/LTO/ThinLTOCodeGenerator.cpp              | 31 ++++++++++---------
 2 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/include/llvm/LTO/legacy/ThinLTOCodeGenerator.h b/include/llvm/LTO/legacy/ThinLTOCodeGenerator.h
index cb4a16cb5b7..0cc3b26e965 100644
--- a/include/llvm/LTO/legacy/ThinLTOCodeGenerator.h
+++ b/include/llvm/LTO/legacy/ThinLTOCodeGenerator.h
@@ -31,6 +31,23 @@ class StringRef;
 class LLVMContext;
 class TargetMachine;
 
+/// Wrapper around MemoryBufferRef, owning the identifier
+class ThinLTOBuffer {
+  std::string OwnedIdentifier;
+  StringRef Buffer;
+
+public:
+  ThinLTOBuffer(StringRef Buffer, StringRef Identifier)
+      : OwnedIdentifier(Identifier), Buffer(Buffer) {}
+
+  MemoryBufferRef getMemBuffer() const {
+    return MemoryBufferRef(Buffer,
+                           {OwnedIdentifier.c_str(), OwnedIdentifier.size()});
+  }
+  StringRef getBuffer() const { return Buffer; }
+  StringRef getBufferIdentifier() const { return OwnedIdentifier; }
+};
+
 /// Helper to gather options relevant to the target machine creation
 struct TargetMachineBuilder {
   Triple TheTriple;
@@ -280,7 +297,7 @@ private:
 
   /// Vector holding the input buffers containing the bitcode modules to
   /// process.
-  std::vector<MemoryBufferRef> Modules;
+  std::vector<ThinLTOBuffer> Modules;
 
   /// Set of symbols that need to be preserved outside of the set of bitcode
   /// files.
diff --git a/lib/LTO/ThinLTOCodeGenerator.cpp b/lib/LTO/ThinLTOCodeGenerator.cpp
index 22b89fe4740..9e3b89bc17c 100644
--- a/lib/LTO/ThinLTOCodeGenerator.cpp
+++ b/lib/LTO/ThinLTOCodeGenerator.cpp
@@ -129,13 +129,13 @@ static void computePrevailingCopies(
 }
 
 static StringMap<MemoryBufferRef>
-generateModuleMap(const std::vector<MemoryBufferRef> &Modules) {
+generateModuleMap(const std::vector<ThinLTOBuffer> &Modules) {
   StringMap<MemoryBufferRef> ModuleMap;
   for (auto &ModuleBuffer : Modules) {
     assert(ModuleMap.find(ModuleBuffer.getBufferIdentifier()) ==
                ModuleMap.end() &&
            "Expect unique Buffer Identifier");
-    ModuleMap[ModuleBuffer.getBufferIdentifier()] = ModuleBuffer;
+    ModuleMap[ModuleBuffer.getBufferIdentifier()] = ModuleBuffer.getMemBuffer();
   }
   return ModuleMap;
 }
@@ -501,13 +501,13 @@ static void initTMBuilder(TargetMachineBuilder &TMBuilder,
 } // end anonymous namespace
 
 void ThinLTOCodeGenerator::addModule(StringRef Identifier, StringRef Data) {
-  MemoryBufferRef Buffer(Data, Identifier);
+  ThinLTOBuffer Buffer(Data, Identifier);
   if (Modules.empty()) {
     // First module added, so initialize the triple and some options
     LLVMContext Context;
     StringRef TripleStr;
-    ErrorOr<std::string> TripleOrErr =
-        expectedToErrorOrAndEmitErrors(Context, getBitcodeTargetTriple(Buffer));
+    ErrorOr<std::string> TripleOrErr = expectedToErrorOrAndEmitErrors(
+        Context, getBitcodeTargetTriple(Buffer.getMemBuffer()));
     if (TripleOrErr)
       TripleStr = *TripleOrErr;
     Triple TheTriple(TripleStr);
@@ -517,8 +517,8 @@ void ThinLTOCodeGenerator::addModule(StringRef Identifier, StringRef Data) {
   else {
     LLVMContext Context;
     StringRef TripleStr;
-    ErrorOr<std::string> TripleOrErr =
-        expectedToErrorOrAndEmitErrors(Context, getBitcodeTargetTriple(Buffer));
+    ErrorOr<std::string> TripleOrErr = expectedToErrorOrAndEmitErrors(
+        Context, getBitcodeTargetTriple(Buffer.getMemBuffer()));
     if (TripleOrErr)
       TripleStr = *TripleOrErr;
     assert(TMBuilder.TheTriple.str() == TripleStr &&
@@ -567,7 +567,8 @@ std::unique_ptr<ModuleSummaryIndex> ThinLTOCodeGenerator::linkCombinedIndex() {
   uint64_t NextModuleId = 0;
   for (auto &ModuleBuffer : Modules) {
     Expected<std::unique_ptr<object::ModuleSummaryIndexObjectFile>> ObjOrErr =
-        object::ModuleSummaryIndexObjectFile::create(ModuleBuffer);
+        object::ModuleSummaryIndexObjectFile::create(
+            ModuleBuffer.getMemBuffer());
     if (!ObjOrErr) {
       // FIXME diagnose
       logAllUnhandledErrors(
@@ -831,8 +832,9 @@ void ThinLTOCodeGenerator::run() {
         Context.setDiscardValueNames(LTODiscardValueNames);
 
         // Parse module now
-        auto TheModule = loadModuleFromBuffer(ModuleBuffer, Context, false,
-                                              /*IsImporting*/ false);
+        auto TheModule =
+            loadModuleFromBuffer(ModuleBuffer.getMemBuffer(), Context, false,
+                                 /*IsImporting*/ false);
 
         // CodeGen
         auto OutputBuffer = codegen(*TheModule);
@@ -922,8 +924,8 @@ void ThinLTOCodeGenerator::run() {
   std::iota(ModulesOrdering.begin(), ModulesOrdering.end(), 0);
   std::sort(ModulesOrdering.begin(), ModulesOrdering.end(),
             [&](int LeftIndex, int RightIndex) {
-              auto LSize = Modules[LeftIndex].getBufferSize();
-              auto RSize = Modules[RightIndex].getBufferSize();
+              auto LSize = Modules[LeftIndex].getBuffer().size();
+              auto RSize = Modules[RightIndex].getBuffer().size();
               return LSize > RSize;
             });
 
@@ -976,8 +978,9 @@ void ThinLTOCodeGenerator::run() {
         }
 
         // Parse module now
-        auto TheModule = loadModuleFromBuffer(ModuleBuffer, Context, false,
-                                              /*IsImporting*/ false);
+        auto TheModule =
+            loadModuleFromBuffer(ModuleBuffer.getMemBuffer(), Context, false,
+                                 /*IsImporting*/ false);
 
         // Save temps: original file.
         saveTempBitcode(*TheModule, SaveTempsDir, count, ".0.original.bc");