[PATCH] D67323: [NewPM][Sancov] Create the Sancov Pass after building the pipelines

[Leonard Chan via Phabricator via cfe-commits]

leonardchan created this revision.
leonardchan added reviewers: chandlerc, phosek.
leonardchan added a project: Sanitizers.
Herald added subscribers: cryptoad, kristof.beyls.
Herald added a project: clang.

We're running into linker errors from missing sancov sections:

  ld.lld: error: relocation refers to a discarded section: __sancov_guards
  >>> defined in user-arm64-ubsan-sancov-full.shlib/obj/third_party/ulib/scudo/scudo.wrappers_c.cc.o
  >>> referenced by common.h:26 (../../zircon/third_party/ulib/scudo/common.h:26)
  ... many other references

I believe this is due to a pass in the default pipeline that somehow discards these sections.  The `ModuleSanitizerCoveragePass` was initially added at the start f the pipeline. This now adds it to the end of the pipeline for optimized and unoptimized builds.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D67323

Files:
  clang/lib/CodeGen/BackendUtil.cpp


Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -1149,16 +1149,6 @@
             EntryExitInstrumenterPass(/*PostInlining=*/false)));
       });
 
-      if (CodeGenOpts.SanitizeCoverageType ||
-          CodeGenOpts.SanitizeCoverageIndirectCalls ||
-          CodeGenOpts.SanitizeCoverageTraceCmp) {
-        auto SancovOpts = getSancovOptsFromCGOpts(CodeGenOpts);
-        PB.registerPipelineStartEPCallback(
-            [SancovOpts](ModulePassManager &MPM) {
-              MPM.addPass(ModuleSanitizerCoveragePass(SancovOpts));
-            });
-      }
-
       // Register callbacks to schedule sanitizer passes at the appropriate part of
       // the pipeline.
       // FIXME: either handle asan/the remaining sanitizers or error out
@@ -1226,6 +1216,13 @@
       }
     }
 
+    if (CodeGenOpts.SanitizeCoverageType ||
+        CodeGenOpts.SanitizeCoverageIndirectCalls ||
+        CodeGenOpts.SanitizeCoverageTraceCmp) {
+      auto SancovOpts = getSancovOptsFromCGOpts(CodeGenOpts);
+      MPM.addPass(ModuleSanitizerCoveragePass(SancovOpts));
+    }
+
     if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
       bool Recover = CodeGenOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
       MPM.addPass(HWAddressSanitizerPass(
@@ -1237,13 +1234,6 @@
     }
 
     if (CodeGenOpts.OptimizationLevel == 0) {
-      if (CodeGenOpts.SanitizeCoverageType ||
-          CodeGenOpts.SanitizeCoverageIndirectCalls ||
-          CodeGenOpts.SanitizeCoverageTraceCmp) {
-        auto SancovOpts = getSancovOptsFromCGOpts(CodeGenOpts);
-        MPM.addPass(ModuleSanitizerCoveragePass(SancovOpts));
-      }
-
       addSanitizersAtO0(MPM, TargetTriple, LangOpts, CodeGenOpts);
     }
   }


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