From 438900938c3ac9d7fac2dd5d2c85ca4b9b2e35f7 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Thu, 3 Oct 2013 18:29:09 +0000
Subject: Optimize linkonce_odr unnamed_addr functions during LTO.

Generalize the API so we can distinguish symbols that are needed just for a DSO
symbol table from those that are used from some native .o.

The symbols that are only wanted for the dso symbol table can be dropped if
llvm can prove every other dso has a copy (linkonce_odr) and the address is not
important (unnamed_addr).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191922 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/LTO/LTOCodeGenerator.cpp | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

(limited to 'lib/LTO/LTOCodeGenerator.cpp')

diff --git a/lib/LTO/LTOCodeGenerator.cpp b/lib/LTO/LTOCodeGenerator.cpp
index 3abb6238b3..e35e33666e 100644
--- a/lib/LTO/LTOCodeGenerator.cpp
+++ b/lib/LTO/LTOCodeGenerator.cpp
@@ -310,6 +310,7 @@ bool LTOCodeGenerator::determineTarget(std::string &errMsg) {
 void LTOCodeGenerator::
 applyRestriction(GlobalValue &GV,
                  std::vector<const char*> &MustPreserveList,
+                 std::vector<const char*> &DSOList,
                  SmallPtrSet<GlobalValue*, 8> &AsmUsed,
                  Mangler &Mangler) {
   SmallString<64> Buffer;
@@ -319,6 +320,8 @@ applyRestriction(GlobalValue &GV,
     return;
   if (MustPreserveSymbols.count(Buffer))
     MustPreserveList.push_back(GV.getName().data());
+  if (DSOSymbols.count(Buffer))
+    DSOList.push_back(GV.getName().data());
   if (AsmUndefinedRefs.count(Buffer))
     AsmUsed.insert(&GV);
 }
@@ -348,17 +351,18 @@ void LTOCodeGenerator::applyScopeRestrictions() {
                      NULL);
   Mangler Mangler(MContext, TargetMach);
   std::vector<const char*> MustPreserveList;
+  std::vector<const char*> DSOList;
   SmallPtrSet<GlobalValue*, 8> AsmUsed;
 
   for (Module::iterator f = mergedModule->begin(),
          e = mergedModule->end(); f != e; ++f)
-    applyRestriction(*f, MustPreserveList, AsmUsed, Mangler);
+    applyRestriction(*f, MustPreserveList, DSOList, AsmUsed, Mangler);
   for (Module::global_iterator v = mergedModule->global_begin(),
          e = mergedModule->global_end(); v !=  e; ++v)
-    applyRestriction(*v, MustPreserveList, AsmUsed, Mangler);
+    applyRestriction(*v, MustPreserveList, DSOList, AsmUsed, Mangler);
   for (Module::alias_iterator a = mergedModule->alias_begin(),
          e = mergedModule->alias_end(); a != e; ++a)
-    applyRestriction(*a, MustPreserveList, AsmUsed, Mangler);
+    applyRestriction(*a, MustPreserveList, DSOList, AsmUsed, Mangler);
 
   GlobalVariable *LLVMCompilerUsed =
     mergedModule->getGlobalVariable("llvm.compiler.used");
@@ -386,7 +390,7 @@ void LTOCodeGenerator::applyScopeRestrictions() {
     LLVMCompilerUsed->setSection("llvm.metadata");
   }
 
-  passes.add(createInternalizePass(MustPreserveList));
+  passes.add(createInternalizePass(MustPreserveList, DSOList));
 
   // apply scope restrictions
   passes.run(*mergedModule);
-- 
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