Don't DCE FreeInst's. We were using those! Patch from Owen Anderson.

[oota-llvm.git] / lib / Transforms / IPO / StripSymbols.cpp

diff --git a/lib/Transforms/IPO/StripSymbols.cpp b/lib/Transforms/IPO/StripSymbols.cpp
index ee60ba2913ef0eb8a58616e01e54c7210ef079e0..cd2396258c41f8b6d99ca1b07bb245cfdebcfbb7 100644 (file)
--- a/lib/Transforms/IPO/StripSymbols.cpp
+++ b/lib/Transforms/IPO/StripSymbols.cpp
@@ -2,8 +2,8 @@
 //
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
@@ -29,6 +29,7 @@
 #include "llvm/ValueSymbolTable.h"
 #include "llvm/TypeSymbolTable.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/ADT/SmallPtrSet.h"
 using namespace llvm;
 
 namespace {
@@ -100,13 +101,33 @@ bool StripSymbols::runOnModule(Module &M) {
   // If we're not just stripping debug info, strip all symbols from the
   // functions and the names from any internal globals.
   if (!OnlyDebugInfo) {
+    SmallPtrSet<const GlobalValue*, 8> llvmUsedValues;
+    if (GlobalVariable *LLVMUsed = M.getGlobalVariable("llvm.used")) {
+      llvmUsedValues.insert(LLVMUsed);
+      // Collect values that are preserved as per explicit request.
+      // llvm.used is used to list these values.
+      if (ConstantArray *Inits = 
+            dyn_cast<ConstantArray>(LLVMUsed->getInitializer())) {
+        for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i) {
+          if (GlobalValue *GV = dyn_cast<GlobalValue>(Inits->getOperand(i)))
+            llvmUsedValues.insert(GV);
+          else if (ConstantExpr *CE =
+                       dyn_cast<ConstantExpr>(Inits->getOperand(i)))
+            if (CE->getOpcode() == Instruction::BitCast)
+              if (GlobalValue *GV = dyn_cast<GlobalValue>(CE->getOperand(0)))
+                llvmUsedValues.insert(GV);
+        }
+      }
+    }
+
     for (Module::global_iterator I = M.global_begin(), E = M.global_end();
-         I != E; ++I)
-      if (I->hasInternalLinkage())
+         I != E; ++I) {
+      if (I->hasInternalLinkage() && llvmUsedValues.count(I) == 0)
         I->setName("");     // Internal symbols can't participate in linkage
+    }
 
     for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
-      if (I->hasInternalLinkage())
+      if (I->hasInternalLinkage() && llvmUsedValues.count(I) == 0)
         I->setName("");     // Internal symbols can't participate in linkage
       StripSymtab(I->getValueSymbolTable());
     }