From b4edfb9af93c39f448ac649edff3be4d17263297 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Mon, 5 Feb 2018 17:17:51 +0000
Subject: [PATCH] LTO: Include dso-local bit in ThinLTO cache key.

Differential Revision: https://reviews.llvm.org/D42713

llvm-svn: 324253
---
 llvm/include/llvm/IR/ModuleSummaryIndex.h         |  2 ++
 llvm/lib/IR/ModuleSummaryIndex.cpp                |  9 +++++++++
 llvm/lib/LTO/LTO.cpp                              |  4 +++-
 llvm/lib/Transforms/Utils/FunctionImportUtils.cpp | 12 ++----------
 llvm/test/LTO/Resolution/X86/cache-dso-local.ll   | 22 ++++++++++++++++++++++
 5 files changed, 38 insertions(+), 11 deletions(-)
 create mode 100644 llvm/test/LTO/Resolution/X86/cache-dso-local.ll

diff --git a/llvm/include/llvm/IR/ModuleSummaryIndex.h b/llvm/include/llvm/IR/ModuleSummaryIndex.h
index a48571a..d75986b 100644
--- a/llvm/include/llvm/IR/ModuleSummaryIndex.h
+++ b/llvm/include/llvm/IR/ModuleSummaryIndex.h
@@ -158,6 +158,8 @@ struct ValueInfo {
   const GlobalValueSummaryMapTy::value_type *getRef() const {
     return RefAndFlag.getPointer();
   }
+
+  bool isDSOLocal() const;
 };
 
 template <> struct DenseMapInfo<ValueInfo> {
diff --git a/llvm/lib/IR/ModuleSummaryIndex.cpp b/llvm/lib/IR/ModuleSummaryIndex.cpp
index ce4c8cc..ce74c00 100644
--- a/llvm/lib/IR/ModuleSummaryIndex.cpp
+++ b/llvm/lib/IR/ModuleSummaryIndex.cpp
@@ -17,6 +17,15 @@
 #include "llvm/Support/Path.h"
 using namespace llvm;
 
+bool ValueInfo::isDSOLocal() const {
+  // Need to check all summaries are local in case of hash collisions.
+  return getSummaryList().size() &&
+         llvm::all_of(getSummaryList(),
+                      [](const std::unique_ptr<GlobalValueSummary> &Summary) {
+                        return Summary->isDSOLocal();
+                      });
+}
+
 // Collect for the given module the list of function it defines
 // (GUID -> Summary).
 void ModuleSummaryIndex::collectDefinedFunctionsForModule(
diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp
index a5bdeac..02d1c75 100644
--- a/llvm/lib/LTO/LTO.cpp
+++ b/llvm/lib/LTO/LTO.cpp
@@ -177,8 +177,10 @@ static void computeCacheKey(
 
   auto AddUsedThings = [&](GlobalValueSummary *GS) {
     if (!GS) return;
-    for (const ValueInfo &VI : GS->refs())
+    for (const ValueInfo &VI : GS->refs()) {
+      AddUnsigned(VI.isDSOLocal());
       AddUsedCfiGlobal(VI.getGUID());
+    }
     if (auto *FS = dyn_cast<FunctionSummary>(GS)) {
       for (auto &TT : FS->type_tests())
         UsedTypeIds.insert(TT);
diff --git a/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp b/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp
index 6b5f593..bf6cce9 100644
--- a/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp
+++ b/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp
@@ -206,16 +206,8 @@ void FunctionImportGlobalProcessing::processGlobalForThinLTO(GlobalValue &GV) {
   // definition.
   if (GV.hasName()) {
     ValueInfo VI = ImportIndex.getValueInfo(GV.getGUID());
-    if (VI) {
-      // Need to check all summaries are local in case of hash collisions.
-      bool IsLocal = VI.getSummaryList().size() &&
-          llvm::all_of(VI.getSummaryList(),
-                       [](const std::unique_ptr<GlobalValueSummary> &Summary) {
-                         return Summary->isDSOLocal();
-                       });
-      if (IsLocal)
-        GV.setDSOLocal(true);
-    }
+    if (VI && VI.isDSOLocal())
+      GV.setDSOLocal(true);
   }
 
   bool DoPromote = false;
diff --git a/llvm/test/LTO/Resolution/X86/cache-dso-local.ll b/llvm/test/LTO/Resolution/X86/cache-dso-local.ll
new file mode 100644
index 0000000..5e5b94c
--- /dev/null
+++ b/llvm/test/LTO/Resolution/X86/cache-dso-local.ll
@@ -0,0 +1,22 @@
+; Tests whether the cache is sensitive to the dso-local bit on referenced
+; globals.
+; RUN: rm -rf %t.cache
+; RUN: opt -module-hash -module-summary -o %t.bc %s
+; RUN: llvm-lto2 run -o %t.o %t.bc -cache-dir %t.cache \
+; RUN:   -r %t.bc,foo,px \
+; RUN:   -r %t.bc,bar,px
+; RUN: llvm-lto2 run -o %t.o %t.bc -cache-dir %t.cache \
+; RUN:   -r %t.bc,foo,plx \
+; RUN:   -r %t.bc,bar,px
+; RUN: ls %t.cache | count 2
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define weak void @foo() {
+  ret void
+}
+
+define weak void()* @bar() {
+  ret void()* @foo
+}
-- 
2.7.4