llvm-6502/lib/Transforms/Scalar/FlattenCFGPass.cpp
Chandler Carruth 7962dbdc65 [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE
definition below all of the header #include lines, lib/Transforms/...
edition.

This one is tricky for two reasons. We again have a couple of passes
that define something else before the includes as well. I've sunk their
name macros with the DEBUG_TYPE.

Also, InstCombine contains headers that need DEBUG_TYPE, so now those
headers #define and #undef DEBUG_TYPE around their code, leaving them
well formed modular headers. Fixing these headers was a large motivation
for all of these changes, as "leaky" macros of this form are hard on the
modules implementation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206844 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-22 02:55:47 +00:00

81 lines
2.3 KiB
C++

//===- FlattenCFGPass.cpp - CFG Flatten Pass ----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements flattening of CFG.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Scalar.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/IR/CFG.h"
#include "llvm/Pass.h"
#include "llvm/Transforms/Utils/Local.h"
using namespace llvm;
#define DEBUG_TYPE "flattencfg"
namespace {
struct FlattenCFGPass : public FunctionPass {
static char ID; // Pass identification, replacement for typeid
public:
FlattenCFGPass() : FunctionPass(ID) {
initializeFlattenCFGPassPass(*PassRegistry::getPassRegistry());
}
bool runOnFunction(Function &F) override;
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<AliasAnalysis>();
}
private:
AliasAnalysis *AA;
};
}
char FlattenCFGPass::ID = 0;
INITIALIZE_PASS_BEGIN(FlattenCFGPass, "flattencfg", "Flatten the CFG", false,
false)
INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
INITIALIZE_PASS_END(FlattenCFGPass, "flattencfg", "Flatten the CFG", false,
false)
// Public interface to the FlattenCFG pass
FunctionPass *llvm::createFlattenCFGPass() { return new FlattenCFGPass(); }
/// iterativelyFlattenCFG - Call FlattenCFG on all the blocks in the function,
/// iterating until no more changes are made.
static bool iterativelyFlattenCFG(Function &F, AliasAnalysis *AA) {
bool Changed = false;
bool LocalChange = true;
while (LocalChange) {
LocalChange = false;
// Loop over all of the basic blocks and remove them if they are unneeded...
//
for (Function::iterator BBIt = F.begin(); BBIt != F.end();) {
if (FlattenCFG(BBIt++, AA)) {
LocalChange = true;
}
}
Changed |= LocalChange;
}
return Changed;
}
bool FlattenCFGPass::runOnFunction(Function &F) {
AA = &getAnalysis<AliasAnalysis>();
bool EverChanged = false;
// iterativelyFlattenCFG can make some blocks dead.
while (iterativelyFlattenCFG(F, AA)) {
removeUnreachableBlocks(F);
EverChanged = true;
}
return EverChanged;
}