From 39ed1db310a69281e3399f3b1d8a137788e8319f Mon Sep 17 00:00:00 2001
From: Mehdi Amini <mehdi.amini@apple.com>
Date: Tue, 10 Jan 2017 00:55:47 +0000
Subject: [PATCH] [ThinLTO] Hash more part of the config to build cache entries

This has been fixed in the "new" LTO API used by Gold/LLD, this is
fixing the same issue in the libLTO API used by ld64 (amongst other)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291518 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/LTO/ThinLTOCodeGenerator.cpp | 36 ++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/lib/LTO/ThinLTOCodeGenerator.cpp b/lib/LTO/ThinLTOCodeGenerator.cpp
index 928f69a17de..a14b86179d6 100644
--- a/lib/LTO/ThinLTOCodeGenerator.cpp
+++ b/lib/LTO/ThinLTOCodeGenerator.cpp
@@ -284,7 +284,8 @@ public:
       const FunctionImporter::ExportSetTy &ExportList,
       const std::map<GlobalValue::GUID, GlobalValue::LinkageTypes> &ResolvedODR,
       const GVSummaryMapTy &DefinedFunctions,
-      const DenseSet<GlobalValue::GUID> &PreservedSymbols) {
+      const DenseSet<GlobalValue::GUID> &PreservedSymbols, unsigned OptLevel,
+      const TargetMachineBuilder &TMBuilder) {
     if (CachePath.empty())
       return;
 
@@ -306,12 +307,42 @@ public:
 
     SHA1 Hasher;
 
+    // Include the parts of the LTO configuration that affect code generation.
+    auto AddString = [&](StringRef Str) {
+      Hasher.update(Str);
+      Hasher.update(ArrayRef<uint8_t>{0});
+    };
+    auto AddUnsigned = [&](unsigned I) {
+      uint8_t Data[4];
+      Data[0] = I;
+      Data[1] = I >> 8;
+      Data[2] = I >> 16;
+      Data[3] = I >> 24;
+      Hasher.update(ArrayRef<uint8_t>{Data, 4});
+    };
+
     // Start with the compiler revision
     Hasher.update(LLVM_VERSION_STRING);
 #ifdef HAVE_LLVM_REVISION
     Hasher.update(LLVM_REVISION);
 #endif
 
+    // Hash the optimization level and the target machine settings.
+    AddString(TMBuilder.MCpu);
+    // FIXME: Hash more of Options. For now all clients initialize Options from
+    // command-line flags (which is unsupported in production), but may set
+    // RelaxELFRelocations. The clang driver can also pass FunctionSections,
+    // DataSections and DebuggerTuning via command line flags.
+    AddUnsigned(TMBuilder.Options.RelaxELFRelocations);
+    AddUnsigned(TMBuilder.Options.FunctionSections);
+    AddUnsigned(TMBuilder.Options.DataSections);
+    AddUnsigned((unsigned)TMBuilder.Options.DebuggerTuning);
+    AddString(TMBuilder.MAttr);
+    if (TMBuilder.RelocModel)
+      AddUnsigned(*TMBuilder.RelocModel);
+    AddUnsigned(TMBuilder.CGOptLevel);
+    AddUnsigned(OptLevel);
+
     Hasher.update(ArrayRef<uint8_t>((uint8_t *)&ModHash[0], sizeof(ModHash)));
     for (auto F : ExportList)
       // The export list can impact the internalization, be conservative here
@@ -928,7 +959,8 @@ void ThinLTOCodeGenerator::run() {
         ModuleCacheEntry CacheEntry(CacheOptions.Path, *Index, ModuleIdentifier,
                                     ImportLists[ModuleIdentifier], ExportList,
                                     ResolvedODR[ModuleIdentifier],
-                                    DefinedFunctions, GUIDPreservedSymbols);
+                                    DefinedFunctions, GUIDPreservedSymbols,
+                                    OptLevel, TMBuilder);
         auto CacheEntryPath = CacheEntry.getEntryPath();
 
         {
-- 
2.40.0