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fix PR8144, a bug where constant merge would merge globals marked

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attribute(used).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113911 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2010-09-15 00:30:11 +00:00
parent 05ae0c6026
commit 49ddd3a1a4
2 changed files with 41 additions and 1 deletions
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28
lib/Transforms/IPO/ConstantMerge.cpp
View File

@ -19,10 +19,12 @@
#define DEBUG_TYPE "constmerge"
#include "llvm/Transforms/IPO.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
@ -46,7 +48,27 @@ INITIALIZE_PASS(ConstantMerge, "constmerge",
ModulePass *llvm::createConstantMergePass() { return new ConstantMerge(); }
/// Find values that are marked as llvm.used.
static void FindUsedValues(GlobalVariable *LLVMUsed,
SmallPtrSet<const GlobalValue*, 8> &UsedValues) {
if (LLVMUsed == 0) return;
ConstantArray *Inits = dyn_cast<ConstantArray>(LLVMUsed->getInitializer());
if (Inits == 0) return;
for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
if (GlobalValue *GV =
dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts()))
UsedValues.insert(GV);
}
bool ConstantMerge::runOnModule(Module &M) {
// Find all the globals that are marked "used". These cannot be merged.
SmallPtrSet<const GlobalValue*, 8> UsedGlobals;
FindUsedValues(M.getGlobalVariable("llvm.used"), UsedGlobals);
FindUsedValues(M.getGlobalVariable("llvm.compiler.used"), UsedGlobals);
// Map unique constant/section pairs to globals. We don't want to merge
// globals in different sections.
DenseMap<Constant*, GlobalVariable*> CMap;
@ -79,9 +101,13 @@ bool ConstantMerge::runOnModule(Module &M) {
// Only process constants with initializers in the default addres space.
if (!GV->isConstant() ||!GV->hasDefinitiveInitializer() ||
GV->getType()->getAddressSpace() != 0 || !GV->getSection().empty())
GV->getType()->getAddressSpace() != 0 || !GV->getSection().empty() ||
// Don't touch values marked with attribute(used).
UsedGlobals.count(GV))
continue;
Constant *Init = GV->getInitializer();
// Check to see if the initializer is already known.

14
test/Transforms/ConstantMerge/dont-merge.ll
View File

@ -28,3 +28,17 @@ define void @test2(i32** %P1, i32 addrspace(30)** %P2) {
store i32 addrspace(30)* @T2b, i32 addrspace(30)** %P2
ret void
}
; PR8144 - Don't merge globals marked attribute(used)
; CHECK: @T3A =
; CHECK: @T3B =
@T3A = internal constant i32 0
@T3B = internal constant i32 0
@llvm.used = appending global [2 x i32*] [i32* @T3A, i32* @T3B], section
"llvm.metadata"
define void @test3() {
call void asm sideeffect "T3A, T3B",""() ; invisible use of T3A and T3B
ret void
}