From e1c173bc77e44fe250d905f9e2399dd8868e51a0 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Tue, 7 Mar 2006 17:56:59 +0000 Subject: [PATCH] Fix ConstantMerge/2006-03-07-DontMergeDiffSections.ll, a problem Jim hypotheticalized about, where we would incorrectly merge two globals in different sections. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26597 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/IPO/ConstantMerge.cpp | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) diff --git a/lib/Transforms/IPO/ConstantMerge.cpp b/lib/Transforms/IPO/ConstantMerge.cpp index b6026f27364..220d0d8722c 100644 --- a/lib/Transforms/IPO/ConstantMerge.cpp +++ b/lib/Transforms/IPO/ConstantMerge.cpp @@ -39,7 +39,9 @@ namespace { ModulePass *llvm::createConstantMergePass() { return new ConstantMerge(); } bool ConstantMerge::runOnModule(Module &M) { - std::map CMap; + // Map unique constant/section pairs to globals. We don't want to merge + // globals in different sections. + std::map, GlobalVariable*> CMap; // Replacements - This vector contains a list of replacements to perform. std::vector > Replacements; @@ -56,23 +58,24 @@ bool ConstantMerge::runOnModule(Module &M) { // because doing so may cause initializers of other globals to be rewritten, // invalidating the Constant* pointers in CMap. // - for (Module::global_iterator GV = M.global_begin(), E = M.global_end(); GV != E; ++GV) - // Only process constants with initializers + for (Module::global_iterator GV = M.global_begin(), E = M.global_end(); + GV != E; ++GV) + // Only process constants with initializers. if (GV->isConstant() && GV->hasInitializer()) { Constant *Init = GV->getInitializer(); - // Check to see if the initializer is already known... - std::map::iterator I = CMap.find(Init); + // Check to see if the initializer is already known. + GlobalVariable *&Slot = CMap[std::make_pair(Init, GV->getSection())]; - if (I == CMap.end()) { // Nope, add it to the map - CMap.insert(I, std::make_pair(Init, GV)); + if (Slot == 0) { // Nope, add it to the map. + Slot = GV; } else if (GV->hasInternalLinkage()) { // Yup, this is a duplicate! // Make all uses of the duplicate constant use the canonical version. - Replacements.push_back(std::make_pair(GV, I->second)); - } else if (I->second->hasInternalLinkage()) { + Replacements.push_back(std::make_pair(GV, Slot)); + } else if (GV->hasInternalLinkage()) { // Make all uses of the duplicate constant use the canonical version. - Replacements.push_back(std::make_pair(I->second, GV)); - I->second = GV; + Replacements.push_back(std::make_pair(Slot, GV)); + Slot = GV; } }