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[sancov] do not instrument nodes that are full pre-dominators 

Summary:
Without tree pruning clang has 2,667,552 points.
Wiht only dominators pruning: 1,515,586.
With both dominators & predominators pruning: 1,340,534.

Differential Revision: http://reviews.llvm.org/D17671

llvm-svn: 262103
This commit is contained in:
Mike Aizatsky 2016-02-27 02:10:27 +00:00
parent 2d4f8f168b
commit 9b53ab7121
1 changed files with 22 additions and 11 deletions
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33
llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
View File

@ -31,6 +31,7 @@
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/EHPersonalities.h"
#include "llvm/Analysis/PostDominators.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/DataLayout.h"
@ -159,8 +160,12 @@ class SanitizerCoverageModule : public ModulePass {
const char *getPassName() const override {
return "SanitizerCoverageModule";
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<PostDominatorTreeWrapperPass>();
}
private:
private:
void InjectCoverageForIndirectCalls(Function &F,
ArrayRef<Instruction *> IndirCalls);
void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets);
@ -305,20 +310,24 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
return true;
}
static bool shouldInstrumentBlock(const BasicBlock *BB,
const DominatorTree *DT) {
static bool shouldInstrumentBlock(const BasicBlock *BB, const DominatorTree *DT,
const PostDominatorTree *PDT) {
if (!ClPruneBlocks)
return true;
if (succ_begin(BB) == succ_end(BB))
return true;
// Check if BB dominates all its successors.
bool DominatesAll = succ_begin(BB) != succ_end(BB);
for (const BasicBlock *SUCC : make_range(succ_begin(BB), succ_end(BB))) {
if (!DT->dominates(BB, SUCC))
return true;
DominatesAll &= DT->dominates(BB, SUCC);
}
return false;
// Check if BB pre-dominates all predecessors.
bool PreDominatesAll = pred_begin(BB) != pred_end(BB);
for (const BasicBlock *PRED : make_range(pred_begin(BB), pred_end(BB))) {
PreDominatesAll &= PDT->dominates(BB, PRED);
}
return !(DominatesAll || PreDominatesAll);
}
bool SanitizerCoverageModule::runOnFunction(Function &F) {
@ -338,10 +347,12 @@ bool SanitizerCoverageModule::runOnFunction(Function &F) {
SmallVector<Instruction*, 8> CmpTraceTargets;
SmallVector<Instruction*, 8> SwitchTraceTargets;
DominatorTree DT;
DT.recalculate(F);
DominatorTree *DT = &getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
PostDominatorTree *PDT =
&getAnalysis<PostDominatorTreeWrapperPass>(F).getPostDomTree();
for (auto &BB : F) {
if (shouldInstrumentBlock(&BB, &DT))
if (shouldInstrumentBlock(&BB, DT, PDT))
BlocksToInstrument.push_back(&BB);
for (auto &Inst : BB) {
if (Options.IndirectCalls) {