[MSan] add KMSAN support to Clang driver

Boilerplate code for using KMSAN instrumentation in Clang.

We add a new command line flag, -fsanitize=kernel-memory, with a
corresponding SanitizerKind::KernelMemory, which, along with
SanitizerKind::Memory, maps to the memory_sanitizer feature.

KMSAN is only supported on x86_64 Linux.

It's incompatible with other sanitizers, but supports code coverage
instrumentation.

llvm-svn: 341641

1 files changed, 21 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 3fd01a73251..45be10f005b 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -265,14 +265,15 @@ static void addKernelHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
       /*CompileKernel*/ true, /*Recover*/ true));
 }
 
-static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
-                                   legacy::PassManagerBase &PM) {
+static void addGeneralOptsForMemorySanitizer(const PassManagerBuilder &Builder,
+                                             legacy::PassManagerBase &PM,
+                                             bool CompileKernel) {
   const PassManagerBuilderWrapper &BuilderWrapper =
       static_cast<const PassManagerBuilderWrapper&>(Builder);
   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
   int TrackOrigins = CGOpts.SanitizeMemoryTrackOrigins;
   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Memory);
-  PM.add(createMemorySanitizerPass(TrackOrigins, Recover));
+  PM.add(createMemorySanitizerPass(TrackOrigins, Recover, CompileKernel));
 
   // MemorySanitizer inserts complex instrumentation that mostly follows
   // the logic of the original code, but operates on "shadow" values.
@@ -287,6 +288,16 @@ static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
   }
 }
 
+static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
+                                   legacy::PassManagerBase &PM) {
+  addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ false);
+}
+
+static void addKernelMemorySanitizerPass(const PassManagerBuilder &Builder,
+                                         legacy::PassManagerBase &PM) {
+  addGeneralOptsForMemorySanitizer(Builder, PM, /*CompileKernel*/ true);
+}
+
 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
                                    legacy::PassManagerBase &PM) {
   PM.add(createThreadSanitizerPass());
@@ -614,6 +625,13 @@ void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
                            addMemorySanitizerPass);
   }
 
+  if (LangOpts.Sanitize.has(SanitizerKind::KernelMemory)) {
+    PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
+                           addKernelMemorySanitizerPass);
+    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
+                           addKernelMemorySanitizerPass);
+  }
+
   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
                            addThreadSanitizerPass);