1 files changed, 36 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp b/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
index 01938a0f357..084e6b7e436 100644
--- a/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -109,6 +109,8 @@ private:
   insertCounterWriteout(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
   Function *insertFlush(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
 
+  void AddFlushBeforeForkAndExec();
+
   enum class GCovFileType { GCNO, GCDA };
   std::string mangleName(const DICompileUnit *CU, GCovFileType FileType);
 
@@ -468,6 +470,8 @@ bool GCOVProfiler::runOnModule(Module &M, const TargetLibraryInfo &TLI) {
   this->TLI = &TLI;
   Ctx = &M.getContext();
 
+  AddFlushBeforeForkAndExec();
+
   if (Options.EmitNotes) emitProfileNotes();
   if (Options.EmitData) return emitProfileArcs();
   return false;
@@ -524,6 +528,38 @@ static bool shouldKeepInEntry(BasicBlock::iterator It) {
 	return false;
 }
 
+void GCOVProfiler::AddFlushBeforeForkAndExec() {
+  SmallVector<Instruction *, 2> ForkAndExecs;
+  for (auto &F : M->functions()) {
+    for (auto &I : instructions(F)) {
+      if (CallInst *CI = dyn_cast<CallInst>(&I)) {
+        if (Function *Callee = CI->getCalledFunction()) {
+          LibFunc LF;
+          if (TLI->getLibFunc(*Callee, LF) &&
+              (LF == LibFunc_fork || LF == LibFunc_execl ||
+               LF == LibFunc_execle || LF == LibFunc_execlp ||
+               LF == LibFunc_execv || LF == LibFunc_execvp ||
+               LF == LibFunc_execve || LF == LibFunc_execvpe ||
+               LF == LibFunc_execvP)) {
+            ForkAndExecs.push_back(&I);
+          }
+        }
+      }
+    }
+  }
+
+  // We need to split the block after the fork/exec call
+  // because else the counters for the lines after will be
+  // the same as before the call.
+  for (auto I : ForkAndExecs) {
+    IRBuilder<> Builder(I);
+    FunctionType *FTy = FunctionType::get(Builder.getVoidTy(), {}, false);
+    Constant *GCOVFlush = M->getOrInsertFunction("__gcov_flush", FTy);
+    Builder.CreateCall(GCOVFlush);
+    I->getParent()->splitBasicBlock(I);
+  }
+}
+
 void GCOVProfiler::emitProfileNotes() {
   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
   if (!CU_Nodes) return;