[asan/coverage] change the way asan coverage instrumentation is done: instead of...

llvm-svn: 222675

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep.cc b/compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
index bd98adb..af8f943 100644 (file)
--- a/compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
@@ -12,14 +12,14 @@
 //
 // Compiler instrumentation:
 // For every interesting basic block the compiler injects the following code:
-// if (*Guard) {
-//    __sanitizer_cov();
-//    *Guard = 1;
+// if (Guard) {
+//    __sanitizer_cov(&Guard);
 // }
 // It's fine to call __sanitizer_cov more than once for a given block.
 //
 // Run-time:
 //  - __sanitizer_cov(): record that we've executed the PC (GET_CALLER_PC).
+//    and atomically set Guard to 1.
 //  - __sanitizer_cov_dump: dump the coverage data to disk.
 //  For every module of the current process that has coverage data
 //  this will create a file module_name.PID.sancov. The file format is simple:
@@ -65,7 +65,7 @@ class CoverageData {
   void BeforeFork();
   void AfterFork(int child_pid);
   void Extend(uptr npcs);
-  void Add(uptr pc);
+  void Add(uptr pc, u8 *guard);
   void IndirCall(uptr caller, uptr callee, uptr callee_cache[],
                  uptr cache_size);
   void DumpCallerCalleePairs();
@@ -230,15 +230,19 @@ void CoverageData::Extend(uptr npcs) {
   atomic_store(&pc_array_size, size, memory_order_release);
 }
 
-// Simply add the pc into the vector under lock. If the function is called more
-// than once for a given PC it will be inserted multiple times, which is fine.
-void CoverageData::Add(uptr pc) {
+// Atomically add the pc to the vector. The atomically set the guard to 1.
+// If the function is called more than once for a given PC it will
+// be inserted multiple times, which is fine.
+void CoverageData::Add(uptr pc, u8 *guard) {
   if (!pc_array) return;
   uptr idx = atomic_fetch_add(&pc_array_index, 1, memory_order_relaxed);
   CHECK_LT(idx * sizeof(uptr),
            atomic_load(&pc_array_size, memory_order_acquire));
   pc_array[idx] = pc;
   atomic_fetch_add(&coverage_counter, 1, memory_order_relaxed);
+  // Set the guard.
+  atomic_uint8_t *atomic_guard = reinterpret_cast<atomic_uint8_t*>(guard);
+  atomic_store(atomic_guard, 1, memory_order_relaxed);
 }
 
 // Registers a pair caller=>callee.
@@ -537,8 +541,9 @@ void CovAfterFork(int child_pid) {
 }  // namespace __sanitizer
 
 extern "C" {
-SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov() {
-  coverage_data.Add(StackTrace::GetPreviousInstructionPc(GET_CALLER_PC()));
+SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov(u8 *guard) {
+  coverage_data.Add(StackTrace::GetPreviousInstructionPc(GET_CALLER_PC()),
+                    guard);
 }
 SANITIZER_INTERFACE_ATTRIBUTE void
 __sanitizer_cov_indir_call16(uptr callee, uptr callee_cache16[]) {

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h b/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
index d77ca8f..97eef74 100644 (file)
--- a/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
@@ -120,7 +120,7 @@ extern "C" {
 
   SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_dump();
   SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_init();
-  SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov();
+  SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov(__sanitizer::u8 *guard);
   SANITIZER_INTERFACE_ATTRIBUTE
   void __sanitizer_annotate_contiguous_container(const void *beg,
                                                  const void *end,

diff --git a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
index f882072..60d7f9f 100644 (file)
--- a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -13,9 +13,8 @@
 // We create a Guard boolean variable with the same linkage
 // as the function and inject this code into the entry block (CoverageLevel=1)
 // or all blocks (CoverageLevel>=2):
-// if (*Guard) {
-//    __sanitizer_cov();
-//    *Guard = 1;
+// if (Guard) {
+//    __sanitizer_cov(&Guard);
 // }
 // The accesses to Guard are atomic. The rest of the logic is
 // in __sanitizer_cov (it's fine to call it more than once).
@@ -132,6 +131,7 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
   DataLayoutPass *DLP = &getAnalysis<DataLayoutPass>();
   IntptrTy = Type::getIntNTy(*C, DLP->getDataLayout().getPointerSizeInBits());
   Type *VoidTy = Type::getVoidTy(*C);
+  IRBuilder<> IRB(*C);
 
   Function *CtorFunc =
       Function::Create(FunctionType::get(VoidTy, false),
@@ -139,8 +139,8 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
   ReturnInst::Create(*C, BasicBlock::Create(*C, "", CtorFunc));
   appendToGlobalCtors(M, CtorFunc, kSanCtorAndDtorPriority);
 
-  SanCovFunction =
-      checkInterfaceFunction(M.getOrInsertFunction(kSanCovName, VoidTy, nullptr));
+  SanCovFunction = checkInterfaceFunction(
+      M.getOrInsertFunction(kSanCovName, VoidTy, IRB.getInt8PtrTy(), nullptr));
   SanCovIndirCallFunction = checkInterfaceFunction(M.getOrInsertFunction(
       kSanCovIndirCallName, VoidTy, IntptrTy, IntptrTy, nullptr));
   SanCovModuleInit = checkInterfaceFunction(M.getOrInsertFunction(
@@ -157,7 +157,7 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
   for (auto &F : M)
     runOnFunction(F);
 
-  IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator());
+  IRB.SetInsertPoint(CtorFunc->getEntryBlock().getTerminator());
   IRB.CreateCall(SanCovModuleInit,
                  ConstantInt::get(IntptrTy, SanCovFunction->getNumUses()));
   return true;
@@ -279,10 +279,7 @@ void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F,
   IRB.SetInsertPoint(Ins);
   IRB.SetCurrentDebugLocation(EntryLoc);
   // __sanitizer_cov gets the PC of the instruction using GET_CALLER_PC.
-  IRB.CreateCall(SanCovFunction);
-  StoreInst *Store = IRB.CreateStore(ConstantInt::get(Int8Ty, 1), Guard);
-  Store->setAtomic(Monotonic);
-  Store->setAlignment(1);
+  IRB.CreateCall(SanCovFunction, Guard);
 }
 
 char SanitizerCoverageModule::ID = 0;

diff --git a/llvm/test/Instrumentation/SanitizerCoverage/coverage-dbg.ll b/llvm/test/Instrumentation/SanitizerCoverage/coverage-dbg.ll
index eea93b8..3520f8a 100644 (file)
--- a/llvm/test/Instrumentation/SanitizerCoverage/coverage-dbg.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/coverage-dbg.ll
@@ -15,7 +15,7 @@
 ; and add sanitize_address to @_ZN1A1fEv
 
 ; Test that __sanitizer_cov call has !dbg pointing to the opening { of A::f().
-; CHECK: call void @__sanitizer_cov(), !dbg [[A:!.*]]
+; CHECK: call void @__sanitizer_cov(i8*{{.*}}), !dbg [[A:!.*]]
 ; CHECK: [[A]] = metadata !{i32 6, i32 0, metadata !{{.*}}, null}
 
 

diff --git a/llvm/test/Instrumentation/SanitizerCoverage/coverage.ll b/llvm/test/Instrumentation/SanitizerCoverage/coverage.ll
index da0498d..2d9a56a 100644 (file)
--- a/llvm/test/Instrumentation/SanitizerCoverage/coverage.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/coverage.ll
@@ -36,9 +36,9 @@ entry:
 ; CHECK1: %0 = load atomic i8* @__sancov_gen_cov_foo monotonic, align 1
 ; CHECK1: %1 = icmp eq i8 0, %0
 ; CHECK1: br i1 %1, label %2, label %3
-; CHECK1: call void @__sanitizer_cov
+; CHECK1: call void @__sanitizer_cov(i8*{{.*}})
 ; CHECK1-NOT: call void @__sanitizer_cov
-; CHECK1: store atomic i8 1, i8* @__sancov_gen_cov_foo monotonic, align 1
+; CHECK1: ret void
 
 ; CHECK1-LABEL: define internal void @sancov.module_ctor
 ; CHECK1-NOT: ret

diff --git a/llvm/test/Instrumentation/SanitizerCoverage/coverage2-dbg.ll b/llvm/test/Instrumentation/SanitizerCoverage/coverage2-dbg.ll
index 9b26329..f351fe1 100644 (file)
--- a/llvm/test/Instrumentation/SanitizerCoverage/coverage2-dbg.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/coverage2-dbg.ll
@@ -17,9 +17,9 @@ target triple = "x86_64-unknown-linux-gnu"
 ; Check that __sanitizer_cov call has !dgb pointing to the beginning
 ; of appropriate basic blocks.
 ; CHECK-LABEL:_Z3fooPi
-; CHECK: call void @__sanitizer_cov(), !dbg [[A:!.*]]
-; CHECK: call void @__sanitizer_cov(), !dbg [[B:!.*]]
-; CHECK: call void @__sanitizer_cov(), !dbg [[C:!.*]]
+; CHECK: call void @__sanitizer_cov(i8*{{.*}}), !dbg [[A:!.*]]
+; CHECK: call void @__sanitizer_cov(i8*{{.*}}), !dbg [[B:!.*]]
+; CHECK: call void @__sanitizer_cov(i8*{{.*}}), !dbg [[C:!.*]]
 ; CHECK: ret void
 ; CHECK: [[A]] = metadata !{i32 1, i32 0, metadata !{{.*}}, null}
 ; CHECK: [[B]] = metadata !{i32 3, i32 5, metadata !{{.*}}, null}