From f5377021c55e7ffc158488fb94d580772573d978 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Fri, 22 Aug 2014 01:18:18 +0000
Subject: [PATCH] [dfsan] Fix non-determinism bug in non-zero label check
 annotator.

We now use a std::vector instead of a DenseSet to store the list of
label checks so that we can iterate over it deterministically.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216255 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../Instrumentation/DataFlowSanitizer.cpp      | 18 ++++++++----------
 .../DataFlowSanitizer/debug-nonzero-labels.ll  | 13 ++++++++-----
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
index 9f5e0bb844d..6323a56d06f 100644
--- a/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -280,7 +280,7 @@ struct DFSanFunction {
   DenseMap<AllocaInst *, AllocaInst *> AllocaShadowMap;
   std::vector<std::pair<PHINode *, PHINode *> > PHIFixups;
   DenseSet<Instruction *> SkipInsts;
-  DenseSet<Value *> NonZeroChecks;
+  std::vector<Value *> NonZeroChecks;
   bool AvoidNewBlocks;
 
   struct CachedCombinedShadow {
@@ -802,18 +802,16 @@ bool DataFlowSanitizer::runOnModule(Module &M) {
     // yet).  To make our life easier, do this work in a pass after the main
     // instrumentation.
     if (ClDebugNonzeroLabels) {
-      for (DenseSet<Value *>::iterator i = DFSF.NonZeroChecks.begin(),
-                                       e = DFSF.NonZeroChecks.end();
-           i != e; ++i) {
+      for (Value *V : DFSF.NonZeroChecks) {
         Instruction *Pos;
-        if (Instruction *I = dyn_cast<Instruction>(*i))
+        if (Instruction *I = dyn_cast<Instruction>(V))
           Pos = I->getNextNode();
         else
           Pos = DFSF.F->getEntryBlock().begin();
         while (isa<PHINode>(Pos) || isa<AllocaInst>(Pos))
           Pos = Pos->getNextNode();
         IRBuilder<> IRB(Pos);
-        Value *Ne = IRB.CreateICmpNE(*i, DFSF.DFS.ZeroShadow);
+        Value *Ne = IRB.CreateICmpNE(V, DFSF.DFS.ZeroShadow);
         BranchInst *BI = cast<BranchInst>(SplitBlockAndInsertIfThen(
             Ne, Pos, /*Unreachable=*/false, ColdCallWeights));
         IRBuilder<> ThenIRB(BI);
@@ -878,7 +876,7 @@ Value *DFSanFunction::getShadow(Value *V) {
         break;
       }
       }
-      NonZeroChecks.insert(Shadow);
+      NonZeroChecks.push_back(Shadow);
     } else {
       Shadow = DFS.ZeroShadow;
     }
@@ -1138,7 +1136,7 @@ void DFSanVisitor::visitLoadInst(LoadInst &LI) {
     Shadow = DFSF.combineShadows(Shadow, PtrShadow, &LI);
   }
   if (Shadow != DFSF.DFS.ZeroShadow)
-    DFSF.NonZeroChecks.insert(Shadow);
+    DFSF.NonZeroChecks.push_back(Shadow);
 
   DFSF.setShadow(&LI, Shadow);
 }
@@ -1480,7 +1478,7 @@ void DFSanVisitor::visitCallSite(CallSite CS) {
       LoadInst *LI = NextIRB.CreateLoad(DFSF.getRetvalTLS());
       DFSF.SkipInsts.insert(LI);
       DFSF.setShadow(CS.getInstruction(), LI);
-      DFSF.NonZeroChecks.insert(LI);
+      DFSF.NonZeroChecks.push_back(LI);
     }
   }
 
@@ -1534,7 +1532,7 @@ void DFSanVisitor::visitCallSite(CallSite CS) {
           ExtractValueInst::Create(NewCS.getInstruction(), 1, "", Next);
       DFSF.SkipInsts.insert(ExShadow);
       DFSF.setShadow(ExVal, ExShadow);
-      DFSF.NonZeroChecks.insert(ExShadow);
+      DFSF.NonZeroChecks.push_back(ExShadow);
 
       CS.getInstruction()->replaceAllUsesWith(ExVal);
     }
diff --git a/test/Instrumentation/DataFlowSanitizer/debug-nonzero-labels.ll b/test/Instrumentation/DataFlowSanitizer/debug-nonzero-labels.ll
index 6bcd5c5f0c1..eb28c2c5245 100644
--- a/test/Instrumentation/DataFlowSanitizer/debug-nonzero-labels.ll
+++ b/test/Instrumentation/DataFlowSanitizer/debug-nonzero-labels.ll
@@ -3,13 +3,16 @@ target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f3
 
 declare i32 @g()
 
-; CHECK: define { i32, i16 } @"dfs$f"(i32, i16)
-define i32 @f(i32) {
+; CHECK: define { i32, i16 } @"dfs$f"(i32, i32, i16, i16)
+define i32 @f(i32, i32) {
   ; CHECK: [[LOCALLABELALLOCA:%.*]] = alloca i16
-  ; CHECK: [[ARGCMP:%.*]] = icmp ne i16 %1, 0
-  ; CHECK: br i1 [[ARGCMP]]
   %i = alloca i32
-  store i32 %0, i32* %i
+  ; CHECK: [[ARGCMP1:%.*]] = icmp ne i16 %3, 0
+  ; CHECK: br i1 [[ARGCMP1]]
+  ; CHECK: [[ARGCMP2:%.*]] = icmp ne i16 %2, 0
+  ; CHECK: br i1 [[ARGCMP2]]
+  %x = add i32 %0, %1
+  store i32 %x, i32* %i
   ; CHECK: [[CALL:%.*]] = call { i32, i16 } @"dfs$g"()
   ; CHECK: [[CALLLABEL:%.*]] = extractvalue { i32, i16 } [[CALL]], 1
   ; CHECK: [[CALLCMP:%.*]] = icmp ne i16 [[CALLLABEL]], 0