From 67af0456bc713b1f27e7b38bae1bf707172b8cdf Mon Sep 17 00:00:00 2001 From: "Duncan P. N. Exon Smith" Date: Tue, 14 Jan 2014 06:37:26 +0000 Subject: LTO: add API to set strategy for -internalize Add API to LTOCodeGenerator to specify a strategy for the -internalize pass. This is a new attempt at Bill's change in r185882, which he reverted in r188029 due to problems with the gold linker. This puts the onus on the linker to decide whether (and what) to internalize. In particular, running internalize before outputting an object file may change a 'weak' symbol into an internal one, even though that symbol could be needed by an external object file --- e.g., with arclite. This patch enables three strategies: - LTO_INTERNALIZE_FULL: the default (and the old behaviour). - LTO_INTERNALIZE_NONE: skip -internalize. - LTO_INTERNALIZE_HIDDEN: only -internalize symbols with hidden visibility. LTO_INTERNALIZE_FULL should be used when linking an executable. Outputting an object file (e.g., via ld -r) is more complicated, and depends on whether hidden symbols should be internalized. E.g., for ld -r, LTO_INTERNALIZE_NONE can be used when -keep_private_externs, and LTO_INTERNALIZE_HIDDEN can be used otherwise. However, LTO_INTERNALIZE_FULL is inappropriate, since the output object file will eventually need to link with others. lto_codegen_set_internalize_strategy() sets the strategy for subsequent calls to lto_codegen_write_merged_modules() and lto_codegen_compile*(). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199191 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/IPO/Internalize.cpp | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-) (limited to 'lib/Transforms') diff --git a/lib/Transforms/IPO/Internalize.cpp b/lib/Transforms/IPO/Internalize.cpp index dae69ce091..775ca96851 100644 --- a/lib/Transforms/IPO/Internalize.cpp +++ b/lib/Transforms/IPO/Internalize.cpp @@ -54,10 +54,11 @@ APIList("internalize-public-api-list", cl::value_desc("list"), namespace { class InternalizePass : public ModulePass { std::set ExternalNames; + bool OnlyHidden; public: static char ID; // Pass identification, replacement for typeid - explicit InternalizePass(); - explicit InternalizePass(ArrayRef ExportList); + explicit InternalizePass(bool OnlyHidden = false); + explicit InternalizePass(ArrayRef ExportList, bool OnlyHidden); void LoadFile(const char *Filename); virtual bool runOnModule(Module &M); @@ -72,16 +73,17 @@ char InternalizePass::ID = 0; INITIALIZE_PASS(InternalizePass, "internalize", "Internalize Global Symbols", false, false) -InternalizePass::InternalizePass() - : ModulePass(ID) { +InternalizePass::InternalizePass(bool OnlyHidden) + : ModulePass(ID), OnlyHidden(OnlyHidden) { initializeInternalizePassPass(*PassRegistry::getPassRegistry()); if (!APIFile.empty()) // If a filename is specified, use it. LoadFile(APIFile.c_str()); ExternalNames.insert(APIList.begin(), APIList.end()); } -InternalizePass::InternalizePass(ArrayRef ExportList) - : ModulePass(ID){ +InternalizePass::InternalizePass(ArrayRef ExportList, + bool OnlyHidden) + : ModulePass(ID), OnlyHidden(OnlyHidden) { initializeInternalizePassPass(*PassRegistry::getPassRegistry()); for(ArrayRef::const_iterator itr = ExportList.begin(); itr != ExportList.end(); itr++) { @@ -106,7 +108,11 @@ void InternalizePass::LoadFile(const char *Filename) { } static bool shouldInternalize(const GlobalValue &GV, - const std::set &ExternalNames) { + const std::set &ExternalNames, + bool OnlyHidden) { + if (OnlyHidden && !GV.hasHiddenVisibility()) + return false; + // Function must be defined here if (GV.isDeclaration()) return false; @@ -155,9 +161,8 @@ bool InternalizePass::runOnModule(Module &M) { } // Mark all functions not in the api as internal. - // FIXME: maybe use private linkage? for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) { - if (!shouldInternalize(*I, ExternalNames)) + if (!shouldInternalize(*I, ExternalNames, OnlyHidden)) continue; I->setLinkage(GlobalValue::InternalLinkage); @@ -191,10 +196,9 @@ bool InternalizePass::runOnModule(Module &M) { // Mark all global variables with initializers that are not in the api as // internal as well. - // FIXME: maybe use private linkage? for (Module::global_iterator I = M.global_begin(), E = M.global_end(); I != E; ++I) { - if (!shouldInternalize(*I, ExternalNames)) + if (!shouldInternalize(*I, ExternalNames, OnlyHidden)) continue; I->setLinkage(GlobalValue::InternalLinkage); @@ -206,7 +210,7 @@ bool InternalizePass::runOnModule(Module &M) { // Mark all aliases that are not in the api as internal as well. for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end(); I != E; ++I) { - if (!shouldInternalize(*I, ExternalNames)) + if (!shouldInternalize(*I, ExternalNames, OnlyHidden)) continue; I->setLinkage(GlobalValue::InternalLinkage); @@ -218,10 +222,11 @@ bool InternalizePass::runOnModule(Module &M) { return Changed; } -ModulePass *llvm::createInternalizePass() { - return new InternalizePass(); +ModulePass *llvm::createInternalizePass(bool OnlyHidden) { + return new InternalizePass(OnlyHidden); } -ModulePass *llvm::createInternalizePass(ArrayRef ExportList) { - return new InternalizePass(ExportList); +ModulePass *llvm::createInternalizePass(ArrayRef ExportList, + bool OnlyHidden) { + return new InternalizePass(ExportList, OnlyHidden); } -- cgit v1.2.3