[PATCH] D32064: [asan] Disable ASan global-GC depending on the target and CGOpts

[Evgeniy Stepanov via Phabricator via cfe-commits]

eugenis created this revision.

The linux part is a bit ahead of time - the instrumentation code where this matters have not landed yet. But when it does, this would be the right condition, and for now ELF instrumentation simply ignores this setting.


Repository:
  rL LLVM

https://reviews.llvm.org/D32064

Files:
  lib/CodeGen/BackendUtil.cpp


Index: lib/CodeGen/BackendUtil.cpp
===================================================================
--- lib/CodeGen/BackendUtil.cpp
+++ lib/CodeGen/BackendUtil.cpp
@@ -132,16 +132,20 @@
 // that we add to the PassManagerBuilder.
 class PassManagerBuilderWrapper : public PassManagerBuilder {
 public:
-  PassManagerBuilderWrapper(const CodeGenOptions &CGOpts,
+  PassManagerBuilderWrapper(const Triple &TargetTriple,
+                            const CodeGenOptions &CGOpts,
                             const LangOptions &LangOpts)
-      : PassManagerBuilder(), CGOpts(CGOpts), LangOpts(LangOpts) {}
+      : PassManagerBuilder(), TargetTriple(TargetTriple), CGOpts(CGOpts),
+        LangOpts(LangOpts) {}
+  const Triple &getTargetTriple() const { return TargetTriple; }
   const CodeGenOptions &getCGOpts() const { return CGOpts; }
   const LangOptions &getLangOpts() const { return LangOpts; }
+
 private:
+  const Triple &TargetTriple;
   const CodeGenOptions &CGOpts;
   const LangOptions &LangOpts;
 };
-
 }
 
 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
@@ -188,16 +192,36 @@
   PM.add(createSanitizerCoverageModulePass(Opts));
 }
 
+// Check if ASan should use GC-friendly instrumentation for globals.
+// First of all, there is no point if -fdata-sections is off (expect for MachO,
+// where this is not a factor). Also, on ELF this feature requires an assembler
+// extension that only works with -integrated-as at the moment.
+static bool asanUseGlobalsGC(const Triple &T, const CodeGenOptions &CGOpts) {
+  switch (T.getObjectFormat()) {
+  case Triple::MachO:
+    return true;
+  case Triple::COFF:
+    return CGOpts.DataSections;
+  case Triple::ELF:
+    return CGOpts.DataSections && !CGOpts.DisableIntegratedAS;
+  default:
+    return false;
+  }
+}
+
 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
                                       legacy::PassManagerBase &PM) {
   const PassManagerBuilderWrapper &BuilderWrapper =
       static_cast<const PassManagerBuilderWrapper&>(Builder);
+  const Triple &T = BuilderWrapper.getTargetTriple();
   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Address);
   bool UseAfterScope = CGOpts.SanitizeAddressUseAfterScope;
+  bool UseGlobalsGC = asanUseGlobalsGC(T, CGOpts);
   PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/ false, Recover,
                                             UseAfterScope));
-  PM.add(createAddressSanitizerModulePass(/*CompileKernel*/false, Recover));
+  PM.add(createAddressSanitizerModulePass(/*CompileKernel*/ false, Recover,
+                                          UseGlobalsGC));
 }
 
 static void addKernelAddressSanitizerPasses(const PassManagerBuilder &Builder,
@@ -435,16 +459,16 @@
   if (CodeGenOpts.DisableLLVMPasses)
     return;
 
-  PassManagerBuilderWrapper PMBuilder(CodeGenOpts, LangOpts);
-
   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)
   // are inserted before PMBuilder ones - they'd get the default-constructed
   // TLI with an unknown target otherwise.
   Triple TargetTriple(TheModule->getTargetTriple());
   std::unique_ptr<TargetLibraryInfoImpl> TLII(
       createTLII(TargetTriple, CodeGenOpts));
 
+  PassManagerBuilderWrapper PMBuilder(TargetTriple, CodeGenOpts, LangOpts);
+
   // At O0 and O1 we only run the always inliner which is more efficient. At
   // higher optimization levels we run the normal inliner.
   if (CodeGenOpts.OptimizationLevel <= 1) {


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