[PATCH] D122336: [InstrProfiling] No runtime hook for unused funcs

Gulfem Savrun Yeniceri via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Thu Mar 24 08:59:08 PDT 2022


gulfem updated this revision to Diff 417945.
gulfem added a comment.

Addressed phosek's comment.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D122336/new/

https://reviews.llvm.org/D122336

Files:
  clang/test/CoverageMapping/unused_function_no_runtime_hook.cpp
  llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp


Index: llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -558,16 +558,18 @@
   TT = Triple(M.getTargetTriple());
 
   bool MadeChange = false;
-
-  // Emit the runtime hook even if no counters are present.
-  if (needsRuntimeHookUnconditionally(TT))
+  bool NeedsRuntimeHook = needsRuntimeHookUnconditionally(TT);
+  if (NeedsRuntimeHook)
     MadeChange = emitRuntimeHook();
 
   // Improve compile time by avoiding linear scans when there is no work.
   GlobalVariable *CoverageNamesVar =
       M.getNamedGlobal(getCoverageUnusedNamesVarName());
-  if (!containsProfilingIntrinsics(M) && !CoverageNamesVar)
-    return MadeChange;
+  if (!containsProfilingIntrinsics(M)) {
+    if (!CoverageNamesVar || !NeedsRuntimeHook) {
+      return MadeChange;
+    }
+  }
 
   // We did not know how many value sites there would be inside
   // the instrumented function. This is counting the number of instrumented
Index: clang/test/CoverageMapping/unused_function_no_runtime_hook.cpp
===================================================================
--- /dev/null
+++ clang/test/CoverageMapping/unused_function_no_runtime_hook.cpp
@@ -0,0 +1,6 @@
+// RUN: %clang -target x86_64-unknown-fuchsia -fprofile-instr-generate -fcoverage-mapping -emit-llvm -S %s -o - | FileCheck %s
+
+// CHECK-NOT: @__llvm_profile_runtime
+static int f0() {
+  return 100;
+}


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