[llvm-commits] [llvm] r160544 - in /llvm/trunk: lib/Transforms/Instrumentation/AddressSanitizer.cpp test/Instrumentation/AddressSanitizer/basic.ll

[Kostya Serebryany]

Author: kcc
Date: Fri Jul 20 04:54:50 2012
New Revision: 160544

URL: http://llvm.org/viewvc/llvm-project?rev=160544&view=rev
Log:
[asan] make sure that the crash callbacks do not get merged (Chandler's idea: insert an empty InlineAsm). Change the order in which the new BBs are inserted: the slow path BB is insert between old BBs, the crash BB is inserted at the end. Don't create an empty BB (introduced by recent commits). Update the test. The experimental code that does manual crash callback merge will most likely be deleted later. 

Modified:
    llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
    llvm/trunk/test/Instrumentation/AddressSanitizer/basic.ll

Modified: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp?rev=160544&r1=160543&r2=160544&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp Fri Jul 20 04:54:50 2012
@@ -18,6 +18,7 @@
 #include "FunctionBlackList.h"
 #include "llvm/Function.h"
 #include "llvm/IRBuilder.h"
+#include "llvm/InlineAsm.h"
 #include "llvm/IntrinsicInst.h"
 #include "llvm/LLVMContext.h"
 #include "llvm/Module.h"
@@ -224,6 +225,7 @@
   OwningPtr<FunctionBlackList> BL;
   // This array is indexed by AccessIsWrite and log2(AccessSize).
   Function *AsanErrorCallback[2][kNumberOfAccessSizes];
+  InlineAsm *EmptyAsm;
 };
 
 }  // namespace
@@ -276,7 +278,7 @@
   BranchInst *CheckTerm = 0;
   if (!ThenBlock) {
     LLVMContext &C = Head->getParent()->getParent()->getContext();
-    ThenBlock = BasicBlock::Create(C, "", Head->getParent());
+    ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
     CheckTerm = BranchInst::Create(Tail, ThenBlock);
   }
   BranchInst *HeadNewTerm =
@@ -414,7 +416,10 @@
                            Addr, PC);
   else
     Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex], Addr);
-  Call->setDoesNotReturn();
+  // We don't do Call->setDoesNotReturn() because the BB already has
+  // UnreachableInst at the end.
+  // This EmptyAsm is required to avoid callback merge.
+  IRB.CreateCall(EmptyAsm);
   return Call;
 }
 
@@ -483,10 +488,13 @@
 
   size_t Granularity = 1 << MappingScale;
   if (TypeSize < 8 * Granularity) {
-    Instruction *CheckTerm = splitBlockAndInsertIfThen(Cmp);
+    BranchInst *CheckTerm = splitBlockAndInsertIfThen(Cmp);
+    assert(CheckTerm->isUnconditional());
+    BasicBlock *NextBB = CheckTerm->getSuccessor(0);
     IRB.SetInsertPoint(CheckTerm);
     Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
-    splitBlockAndInsertIfThen(Cmp2, CrashBlock);
+    BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
+    ReplaceInstWithInst(CheckTerm, NewTerm);
   } else {
     splitBlockAndInsertIfThen(Cmp, CrashBlock);
   }
@@ -695,6 +703,10 @@
           M.getOrInsertFunction(FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
     }
   }
+  // We insert an empty inline asm after __asan_report* to avoid callback merge.
+  EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
+                            StringRef(""), StringRef(""),
+                            /*hasSideEffects=*/true);
 
   llvm::Triple targetTriple(M.getTargetTriple());
   bool isAndroid = targetTriple.getEnvironment() == llvm::Triple::ANDROIDEABI;

Modified: llvm/trunk/test/Instrumentation/AddressSanitizer/basic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/AddressSanitizer/basic.ll?rev=160544&r1=160543&r2=160544&view=diff
==============================================================================
--- llvm/trunk/test/Instrumentation/AddressSanitizer/basic.ll (original)
+++ llvm/trunk/test/Instrumentation/AddressSanitizer/basic.ll Fri Jul 20 04:54:50 2012
@@ -16,15 +16,6 @@
 ; CHECK:   icmp ne i8
 ; CHECK:   br i1 %{{.*}}, label %{{.*}}, label %{{.*}}
 ;
-; The actual load comes next because ASan adds the last instrumentation block
-; to the end of the function.
-; CHECK:   %tmp1 = load i32* %a
-; CHECK:   ret i32 %tmp1
-
-; The crash block reports the error.
-; CHECK:   call void @__asan_report_load4(i64 %[[LOAD_ADDR]]) noreturn
-; CHECK:   unreachable
-;
 ; First instrumentation block refines the shadow test.
 ; CHECK:   and i64 %[[LOAD_ADDR]], 7
 ; CHECK:   add i64 %{{.*}}, 3
@@ -32,6 +23,16 @@
 ; CHECK:   icmp sge i8 %{{.*}}, %[[LOAD_SHADOW]]
 ; CHECK:   br i1 %{{.*}}, label %{{.*}}, label %{{.*}}
 ;
+; The actual load comes next because ASan adds the crash block
+; to the end of the function.
+; CHECK:   %tmp1 = load i32* %a
+; CHECK:   ret i32 %tmp1
+
+; The crash block reports the error.
+; CHECK:   call void @__asan_report_load4(i64 %[[LOAD_ADDR]])
+; CHECK:   unreachable
+;
+
 
 entry:
   %tmp1 = load i32* %a
@@ -49,15 +50,6 @@
 ; CHECK:   icmp ne i8
 ; CHECK:   br i1 %{{.*}}, label %{{.*}}, label %{{.*}}
 ;
-; The actual store comes next because ASan adds the last instrumentation block
-; to the end of the function.
-; CHECK:   store i32 42, i32* %a
-; CHECK:   ret void
-;
-; The crash block reports the error.
-; CHECK:   call void @__asan_report_store4(i64 %[[STORE_ADDR]]) noreturn
-; CHECK:   unreachable
-;
 ; First instrumentation block refines the shadow test.
 ; CHECK:   and i64 %[[STORE_ADDR]], 7
 ; CHECK:   add i64 %{{.*}}, 3
@@ -65,6 +57,15 @@
 ; CHECK:   icmp sge i8 %{{.*}}, %[[STORE_SHADOW]]
 ; CHECK:   br i1 %{{.*}}, label %{{.*}}, label %{{.*}}
 ;
+; The actual load comes next because ASan adds the crash block
+; to the end of the function.
+; CHECK:   store i32 42, i32* %a
+; CHECK:   ret void
+;
+; The crash block reports the error.
+; CHECK:   call void @__asan_report_store4(i64 %[[STORE_ADDR]])
+; CHECK:   unreachable
+;
 
 entry:
   store i32 42, i32* %a