Reapply "[ubsan] Connect -fsanitize-skip-hot-cutoff to LowerAllowCheckPass<cutoffs>" (#125032) (#125037)

This reverts commit 928cad49beec0120686478f502899222e836b545 i.e.,
relands dccd27112722109d2e2f03e8da9ce8690f06e11b, with a fix to avoid
use-after-scope by changing the lambda to capture by value.

1 files changed, 16 insertions, 7 deletions

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 3e65eeb..97e9bbc 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -795,14 +795,23 @@ static void addSanitizers(const Triple &TargetTriple,
     PB.registerOptimizerLastEPCallback(SanitizersCallback);
   }
 
-  if (LowerAllowCheckPass::IsRequested()) {
+  // SanitizeSkipHotCutoffs: doubles with range [0, 1]
+  // Opts.cutoffs: unsigned ints with range [0, 1000000]
+  auto ScaledCutoffs = CodeGenOpts.SanitizeSkipHotCutoffs.getAllScaled(1000000);
+
+  // TODO: remove IsRequested()
+  if (LowerAllowCheckPass::IsRequested() || ScaledCutoffs.has_value()) {
     // We want to call it after inline, which is about OptimizerEarlyEPCallback.
-    PB.registerOptimizerEarlyEPCallback([&](ModulePassManager &MPM,
-                                            OptimizationLevel Level,
-                                            ThinOrFullLTOPhase Phase) {
-      LowerAllowCheckPass::Options Opts;
-      MPM.addPass(createModuleToFunctionPassAdaptor(LowerAllowCheckPass(Opts)));
-    });
+    PB.registerOptimizerEarlyEPCallback(
+        [ScaledCutoffs](ModulePassManager &MPM, OptimizationLevel Level,
+                        ThinOrFullLTOPhase Phase) {
+          LowerAllowCheckPass::Options Opts;
+          // TODO: after removing IsRequested(), make this unconditional
+          if (ScaledCutoffs.has_value())
+            Opts.cutoffs = ScaledCutoffs.value();
+          MPM.addPass(
+              createModuleToFunctionPassAdaptor(LowerAllowCheckPass(Opts)));
+        });
   }
 }