From e29996c9a2188a38c70457a40de31ec6dd6b0f18 Mon Sep 17 00:00:00 2001
From: Jann Horn <jannh@google.com>
Date: Thu, 30 Apr 2020 11:04:51 +0200
Subject: [PATCH] [AddressSanitizer] Refactor ClDebug{Min,Max} handling

Summary:
A following commit will split the loop over ToInstrument into two.
To avoid having to duplicate the condition for suppressing instrumentation
sites based on ClDebug{Min,Max}, refactor it out into a new function.

While we're at it, we can also avoid the indirection through
NumInstrumented for setting FunctionModified.

This is patch 1/4 of a patch series:
https://reviews.llvm.org/D77616 [PATCH 1/4] [AddressSanitizer] Refactor ClDebug{Min,Max} handling
https://reviews.llvm.org/D77617 [PATCH 2/4] [AddressSanitizer] Split out memory intrinsic handling
https://reviews.llvm.org/D77618 [PATCH 3/4] [AddressSanitizer] Refactor: Permit >1 interesting operands per instruction
https://reviews.llvm.org/D77619 [PATCH 4/4] [AddressSanitizer] Instrument byval call arguments

Reviewers: kcc, glider

Reviewed By: glider

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77616
---
 .../Transforms/Instrumentation/AddressSanitizer.cpp    | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 4556e32..d6dedc6 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -638,6 +638,7 @@ struct AddressSanitizer {
                                  Value *SizeArgument, uint32_t Exp);
   void instrumentMemIntrinsic(MemIntrinsic *MI);
   Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
+  bool suppressInstrumentationSiteForDebug(int &Instrumented);
   bool instrumentFunction(Function &F, const TargetLibraryInfo *TLI);
   bool maybeInsertAsanInitAtFunctionEntry(Function &F);
   void maybeInsertDynamicShadowAtFunctionEntry(Function &F);
@@ -2610,6 +2611,14 @@ void AddressSanitizer::markEscapedLocalAllocas(Function &F) {
   }
 }
 
+bool AddressSanitizer::suppressInstrumentationSiteForDebug(int &Instrumented) {
+  bool ShouldInstrument =
+      ClDebugMin < 0 || ClDebugMax < 0 ||
+      (Instrumented >= ClDebugMin && Instrumented <= ClDebugMax);
+  Instrumented++;
+  return !ShouldInstrument;
+}
+
 bool AddressSanitizer::instrumentFunction(Function &F,
                                           const TargetLibraryInfo *TLI) {
   if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false;
@@ -2710,15 +2719,14 @@ bool AddressSanitizer::instrumentFunction(Function &F,
   // Instrument.
   int NumInstrumented = 0;
   for (auto Inst : ToInstrument) {
-    if (ClDebugMin < 0 || ClDebugMax < 0 ||
-        (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
+    if (!suppressInstrumentationSiteForDebug(NumInstrumented)) {
       if (isInterestingMemoryAccess(Inst, &IsWrite, &TypeSize, &Alignment))
         instrumentMop(ObjSizeVis, Inst, UseCalls,
                       F.getParent()->getDataLayout());
       else
         instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
     }
-    NumInstrumented++;
+    FunctionModified = true;
   }
 
   FunctionStackPoisoner FSP(F, *this);
@@ -2733,10 +2741,10 @@ bool AddressSanitizer::instrumentFunction(Function &F,
 
   for (auto Inst : PointerComparisonsOrSubtracts) {
     instrumentPointerComparisonOrSubtraction(Inst);
-    NumInstrumented++;
+    FunctionModified = true;
   }
 
-  if (NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty())
+  if (ChangedStack || !NoReturnCalls.empty())
     FunctionModified = true;
 
   LLVM_DEBUG(dbgs() << "ASAN done instrumenting: " << FunctionModified << " "
-- 
2.7.4