r371326 - [NewPM][Sancov] Create the Sancov Pass after building the pipelines

[Leonard Chan via cfe-commits]

Author: leonardchan
Date: Sun Sep  8 00:30:17 2019
New Revision: 371326

URL: http://llvm.org/viewvc/llvm-project?rev=371326&view=rev
Log:
[NewPM][Sancov] Create the Sancov Pass after building the pipelines

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 of the pipeline. This now adds it to the end of the pipeline for
optimized and unoptimized builds.

Differential Revision: https://reviews.llvm.org/D67323

Modified:
    cfe/trunk/lib/CodeGen/BackendUtil.cpp

Modified: cfe/trunk/lib/CodeGen/BackendUtil.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/BackendUtil.cpp?rev=371326&r1=371325&r2=371326&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/BackendUtil.cpp (original)
+++ cfe/trunk/lib/CodeGen/BackendUtil.cpp Sun Sep  8 00:30:17 2019
@@ -1149,16 +1149,6 @@ void EmitAssemblyHelper::EmitAssemblyWit
             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 @@ void EmitAssemblyHelper::EmitAssemblyWit
       }
     }
 
+    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 @@ void EmitAssemblyHelper::EmitAssemblyWit
     }
 
     if (CodeGenOpts.OptimizationLevel == 0) {
-      if (CodeGenOpts.SanitizeCoverageType ||
-          CodeGenOpts.SanitizeCoverageIndirectCalls ||
-          CodeGenOpts.SanitizeCoverageTraceCmp) {
-        auto SancovOpts = getSancovOptsFromCGOpts(CodeGenOpts);
-        MPM.addPass(ModuleSanitizerCoveragePass(SancovOpts));
-      }
-
       addSanitizersAtO0(MPM, TargetTriple, LangOpts, CodeGenOpts);
     }
   }