Changes from Duncan's review:

* merge two weak functions by making them both alias a third non-weak fn
 * don't reimplement CallSite::hasArgument
 * whitelist the safe linkage types


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58568 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2008-11-02 16:46:26 +00:00
parent e491515730
commit 6feb333695
2 changed files with 39 additions and 9 deletions

View File

@ -54,6 +54,7 @@
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include <map>
@ -265,6 +266,28 @@ static bool fold(std::vector<Function *> &FnVec, unsigned i, unsigned j) {
}
}
if (F->hasWeakLinkage() && G->hasWeakLinkage()) {
GlobalAlias *GA_F = new GlobalAlias(F->getType(), F->getLinkage(), "",
0, F->getParent());
GA_F->takeName(F);
GA_F->setVisibility(F->getVisibility());
F->setAlignment(std::max(F->getAlignment(), G->getAlignment()));
F->replaceAllUsesWith(GA_F);
F->setName("folded." + GA_F->getName());
F->setLinkage(GlobalValue::ExternalLinkage);
GA_F->setAliasee(F);
GlobalAlias *GA_G = new GlobalAlias(G->getType(), G->getLinkage(), "",
F, G->getParent());
GA_G->takeName(G);
GA_G->setVisibility(G->getVisibility());
G->replaceAllUsesWith(GA_G);
G->eraseFromParent();
++NumFunctionsMerged;
return true;
}
DOUT << "Failed on " << F->getName() << " and " << G->getName() << "\n";
++NumMergeFails;
@ -289,14 +312,10 @@ static bool hasAddressTaken(User *U) {
return true;
// Make sure we aren't passing U as a parameter to call instead of the
// callee. getOperand(0) is the callee for both CallInst and InvokeInst.
// Check the other operands to see if any of them is F.
for (User::op_iterator OI = I->op_begin() + 1, OE = I->op_end(); OI != OE;
++OI) {
if (*OI == U)
// callee.
if (CallSite(cast<Instruction>(Use)).hasArgument(U))
return true;
}
}
return false;
}
@ -310,8 +329,8 @@ bool MergeFunctions::runOnModule(Module &M) {
if (F->isDeclaration() || F->isIntrinsic())
continue;
if (F->hasLinkOnceLinkage() || F->hasCommonLinkage() ||
F->hasDLLImportLinkage() || F->hasDLLExportLinkage())
if (!F->hasInternalLinkage() && !F->hasExternalLinkage() &&
!F->hasWeakLinkage())
continue;
if (hasAddressTaken(F))

View File

@ -0,0 +1,11 @@
; RUN: llvm-as < %s | opt -mergefunc | llvm-dis | grep {alias weak} | count 2
define weak i32 @sum(i32 %x, i32 %y) {
%sum = add i32 %x, %y
ret i32 %sum
}
define weak i32 @add(i32 %x, i32 %y) {
%sum = add i32 %x, %y
ret i32 %sum
}