[ASan] Initial support for Kernel AddressSanitizer

This patch adds initial support for the -fsanitize=kernel-address flag to Clang.
Right now it's quite restricted: only out-of-line instrumentation is supported, globals are not instrumented, some GCC kasan flags are not supported.
Using this patch I am able to build and boot the KASan tree with LLVMLinux patches from github.com/ramosian-glider/kasan/tree/kasan_llvmlinux.
To disable KASan instrumentation for a certain function attribute((no_sanitize("kernel-address"))) can be used.

llvm-svn: 240131

9 files changed, 40 insertions, 12 deletions

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 8eff4c4427b..d9a3389c58f 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -3681,7 +3681,8 @@ void RecordDecl::LoadFieldsFromExternalStorage() const {
 
 bool RecordDecl::mayInsertExtraPadding(bool EmitRemark) const {
   ASTContext &Context = getASTContext();
-  if (!Context.getLangOpts().Sanitize.has(SanitizerKind::Address) ||
+  if (!Context.getLangOpts().Sanitize.hasOneOf(
+          SanitizerKind::Address | SanitizerKind::KernelAddress) ||
       !Context.getLangOpts().SanitizeAddressFieldPadding)
     return false;
   const auto &Blacklist = Context.getSanitizerBlacklist();
diff --git a/clang/lib/Basic/Sanitizers.cpp b/clang/lib/Basic/Sanitizers.cpp
index 8c4884b8ec3..d3676b6b465 100644
--- a/clang/lib/Basic/Sanitizers.cpp
+++ b/clang/lib/Basic/Sanitizers.cpp
@@ -25,6 +25,10 @@ bool SanitizerSet::has(SanitizerMask K) const {
   return Mask & K;
 }
 
+bool SanitizerSet::hasOneOf(SanitizerMask K) const {
+  return Mask & K;
+}
+
 void SanitizerSet::set(SanitizerMask K, bool Value) {
   assert(llvm::countPopulation(K) == 1);
   Mask = Value ? (Mask | K) : (Mask & ~K);
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 30e9ebffa28..f5edea7810a 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -201,8 +201,14 @@ static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
 
 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
                                       legacy::PassManagerBase &PM) {
-  PM.add(createAddressSanitizerFunctionPass());
-  PM.add(createAddressSanitizerModulePass());
+  PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/false));
+  PM.add(createAddressSanitizerModulePass(/*CompileKernel*/false));
+}
+
+static void addKernelAddressSanitizerPasses(const PassManagerBuilder &Builder,
+                                            legacy::PassManagerBase &PM) {
+  PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/true));
+  PM.add(createAddressSanitizerModulePass(/*CompileKernel*/true));
 }
 
 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
@@ -328,6 +334,13 @@ void EmitAssemblyHelper::CreatePasses() {
                            addAddressSanitizerPasses);
   }
 
+  if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
+    PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
+                           addKernelAddressSanitizerPasses);
+    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
+                           addKernelAddressSanitizerPasses);
+  }
+
   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
                            addMemorySanitizerPass);
diff --git a/clang/lib/CodeGen/CGDeclCXX.cpp b/clang/lib/CodeGen/CGDeclCXX.cpp
index 50a499607f8..bae8ab4ea0d 100644
--- a/clang/lib/CodeGen/CGDeclCXX.cpp
+++ b/clang/lib/CodeGen/CGDeclCXX.cpp
@@ -267,7 +267,8 @@ llvm::Function *CodeGenModule::CreateGlobalInitOrDestructFunction(
     Fn->setDoesNotThrow();
 
   if (!isInSanitizerBlacklist(Fn, Loc)) {
-    if (getLangOpts().Sanitize.has(SanitizerKind::Address))
+    if (getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
+                                        SanitizerKind::KernelAddress))
       Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
     if (getLangOpts().Sanitize.has(SanitizerKind::Thread))
       Fn->addFnAttr(llvm::Attribute::SanitizeThread);
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index f370ac27676..bece41e9ecb 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -615,7 +615,7 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
   }
 
   // Apply sanitizer attributes to the function.
-  if (SanOpts.has(SanitizerKind::Address))
+  if (SanOpts.hasOneOf(SanitizerKind::Address | SanitizerKind::KernelAddress))
     Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
   if (SanOpts.has(SanitizerKind::Thread))
     Fn->addFnAttr(llvm::Attribute::SanitizeThread);
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index c0cbe98484f..2dd5414795e 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1218,8 +1218,9 @@ bool CodeGenModule::isInSanitizerBlacklist(llvm::Function *Fn,
 bool CodeGenModule::isInSanitizerBlacklist(llvm::GlobalVariable *GV,
                                            SourceLocation Loc, QualType Ty,
                                            StringRef Category) const {
-  // For now globals can be blacklisted only in ASan.
-  if (!LangOpts.Sanitize.has(SanitizerKind::Address))
+  // For now globals can be blacklisted only in ASan and KASan.
+  if (!LangOpts.Sanitize.hasOneOf(
+          SanitizerKind::Address | SanitizerKind::KernelAddress))
     return false;
   const auto &SanitizerBL = getContext().getSanitizerBlacklist();
   if (SanitizerBL.isBlacklistedGlobal(GV->getName(), Category))
diff --git a/clang/lib/CodeGen/SanitizerMetadata.cpp b/clang/lib/CodeGen/SanitizerMetadata.cpp
index 7c38b2807e9..2a338bac4b4 100644
--- a/clang/lib/CodeGen/SanitizerMetadata.cpp
+++ b/clang/lib/CodeGen/SanitizerMetadata.cpp
@@ -25,7 +25,8 @@ void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
                                            SourceLocation Loc, StringRef Name,
                                            QualType Ty, bool IsDynInit,
                                            bool IsBlacklisted) {
-  if (!CGM.getLangOpts().Sanitize.has(SanitizerKind::Address))
+  if (!CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
+                                           SanitizerKind::KernelAddress))
     return;
   IsDynInit &= !CGM.isInSanitizerBlacklist(GV, Loc, Ty, "init");
   IsBlacklisted |= CGM.isInSanitizerBlacklist(GV, Loc, Ty);
@@ -56,7 +57,8 @@ void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
 
 void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
                                            const VarDecl &D, bool IsDynInit) {
-  if (!CGM.getLangOpts().Sanitize.has(SanitizerKind::Address))
+  if (!CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
+                                           SanitizerKind::KernelAddress))
     return;
   std::string QualName;
   llvm::raw_string_ostream OS(QualName);
@@ -67,7 +69,8 @@ void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
 void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
   // For now, just make sure the global is not modified by the ASan
   // instrumentation.
-  if (CGM.getLangOpts().Sanitize.has(SanitizerKind::Address))
+  if (CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
+                                          SanitizerKind::KernelAddress))
     reportGlobalToASan(GV, SourceLocation(), "", QualType(), false, true);
 }
 
diff --git a/clang/lib/Driver/SanitizerArgs.cpp b/clang/lib/Driver/SanitizerArgs.cpp
index 9918fcbd5e1..4d27a393182 100644
--- a/clang/lib/Driver/SanitizerArgs.cpp
+++ b/clang/lib/Driver/SanitizerArgs.cpp
@@ -305,7 +305,10 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
   std::pair<SanitizerMask, SanitizerMask> IncompatibleGroups[] = {
       std::make_pair(Address, Thread), std::make_pair(Address, Memory),
       std::make_pair(Thread, Memory), std::make_pair(Leak, Thread),
-      std::make_pair(Leak, Memory)};
+      std::make_pair(Leak, Memory), std::make_pair(KernelAddress, Address),
+      std::make_pair(KernelAddress, Leak),
+      std::make_pair(KernelAddress, Thread),
+      std::make_pair(KernelAddress, Memory)};
   for (auto G : IncompatibleGroups) {
     SanitizerMask Group = G.first;
     if (Kinds & Group) {
diff --git a/clang/lib/Lex/PPMacroExpansion.cpp b/clang/lib/Lex/PPMacroExpansion.cpp
index c63cafb6d79..ccfb30240b0 100644
--- a/clang/lib/Lex/PPMacroExpansion.cpp
+++ b/clang/lib/Lex/PPMacroExpansion.cpp
@@ -1049,7 +1049,9 @@ static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
     Feature = Feature.substr(2, Feature.size() - 4);
 
   return llvm::StringSwitch<bool>(Feature)
-      .Case("address_sanitizer", LangOpts.Sanitize.has(SanitizerKind::Address))
+      .Case("address_sanitizer",
+            LangOpts.Sanitize.hasOneOf(SanitizerKind::Address |
+                                       SanitizerKind::KernelAddress))
       .Case("attribute_analyzer_noreturn", true)
       .Case("attribute_availability", true)
       .Case("attribute_availability_with_message", true)