fmayer updated this revision to Diff 358043.
fmayer added a comment.

update


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D105703/new/

https://reviews.llvm.org/D105703

Files:
  clang/lib/CodeGen/BackendUtil.cpp
  clang/test/CodeGen/hwasan-stack-safety-analysis-asm.c
  clang/test/CodeGen/hwasan-stack-safety-analysis.c
  llvm/include/llvm/Transforms/Instrumentation/HWAddressSanitizer.h
  llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp

Index: llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -17,6 +17,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
+#include "llvm/Analysis/StackSafetyAnalysis.h"
 #include "llvm/BinaryFormat/ELF.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
@@ -109,6 +110,10 @@
                                        cl::desc("instrument stack (allocas)"),
                                        cl::Hidden, cl::init(true));
 
+static cl::opt<bool>
+    ClUseStackSafety("hwasan-use-stack-safety", cl::Hidden, cl::init(true),
+                     cl::Hidden, cl::desc("Use Stack Safety analysis results"));
+
 static cl::opt<bool> ClUARRetagToZero(
     "hwasan-uar-retag-to-zero",
     cl::desc("Clear alloca tags before returning from the function to allow "
@@ -192,13 +197,31 @@
 
 namespace {
 
+bool shouldUsePageAliases(const Triple &TargetTriple) {
+  return ClUsePageAliases && TargetTriple.getArch() == Triple::x86_64;
+// No one should use the option directly.
+#pragma GCC poison ClUsePageAliases
+}
+
+bool shouldInstrumentStack(const Triple &TargetTriple) {
+  return shouldUsePageAliases(TargetTriple) ? false : ClInstrumentStack;
+// No one should use the option directly.
+#pragma GCC poison ClInstrumentStack
+}
+
+bool shouldUseStackSafetyAnalysis(const Triple &TargetTriple) {
+  return shouldInstrumentStack(TargetTriple) && ClUseStackSafety;
+// No one should use the option directly.
+#pragma GCC poison ClUseStackSafety
+}
 /// An instrumentation pass implementing detection of addressability bugs
 /// using tagged pointers.
 class HWAddressSanitizer {
 public:
   explicit HWAddressSanitizer(Module &M, bool CompileKernel = false,
-                              bool Recover = false)
-      : M(M) {
+                              bool Recover = false,
+                              const StackSafetyGlobalInfo *SSI = nullptr)
+      : M(M), SSI(SSI) {
     this->Recover = ClRecover.getNumOccurrences() > 0 ? ClRecover : Recover;
     this->CompileKernel = ClEnableKhwasan.getNumOccurrences() > 0
                               ? ClEnableKhwasan
@@ -207,6 +230,8 @@
     initializeModule();
   }
 
+  void setSSI(const StackSafetyGlobalInfo *S) { SSI = S; }
+
   bool sanitizeFunction(Function &F);
   void initializeModule();
   void createHwasanCtorComdat();
@@ -259,6 +284,7 @@
 private:
   LLVMContext *C;
   Module &M;
+  const StackSafetyGlobalInfo *SSI;
   Triple TargetTriple;
   FunctionCallee HWAsanMemmove, HWAsanMemcpy, HWAsanMemset;
   FunctionCallee HWAsanHandleVfork;
@@ -329,8 +355,10 @@
   static char ID;
 
   explicit HWAddressSanitizerLegacyPass(bool CompileKernel = false,
-                                        bool Recover = false)
-      : FunctionPass(ID), CompileKernel(CompileKernel), Recover(Recover) {
+                                        bool Recover = false,
+                                        Triple TargetTriple = {})
+      : FunctionPass(ID), CompileKernel(CompileKernel), Recover(Recover),
+        TargetTriple(TargetTriple) {
     initializeHWAddressSanitizerLegacyPassPass(
         *PassRegistry::getPassRegistry());
   }
@@ -338,11 +366,18 @@
   StringRef getPassName() const override { return "HWAddressSanitizer"; }
 
   bool doInitialization(Module &M) override {
-    HWASan = std::make_unique<HWAddressSanitizer>(M, CompileKernel, Recover);
+    HWASan = std::make_unique<HWAddressSanitizer>(M, CompileKernel, Recover,
+                                                  /*SSI=*/nullptr);
     return true;
   }
 
   bool runOnFunction(Function &F) override {
+    if (shouldUseStackSafetyAnalysis(TargetTriple)) {
+      // We cannot call getAnalysis in doInitialization, that would cause a
+      // crash as the required analyses are not initialized yet.
+      HWASan->setSSI(
+          &getAnalysis<StackSafetyGlobalInfoWrapperPass>().getResult());
+    }
     return HWASan->sanitizeFunction(F);
   }
 
@@ -351,10 +386,17 @@
     return false;
   }
 
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    if (shouldUseStackSafetyAnalysis(TargetTriple)) {
+      AU.addRequired<StackSafetyGlobalInfoWrapperPass>();
+    }
+  }
+
 private:
   std::unique_ptr<HWAddressSanitizer> HWASan;
   bool CompileKernel;
   bool Recover;
+  Triple TargetTriple;
 };
 
 } // end anonymous namespace
@@ -370,18 +412,25 @@
     "HWAddressSanitizer: detect memory bugs using tagged addressing.", false,
     false)
 
-FunctionPass *llvm::createHWAddressSanitizerLegacyPassPass(bool CompileKernel,
-                                                           bool Recover) {
+FunctionPass *
+llvm::createHWAddressSanitizerLegacyPassPass(bool CompileKernel, bool Recover,
+                                             Triple TargetTriple) {
   assert(!CompileKernel || Recover);
-  return new HWAddressSanitizerLegacyPass(CompileKernel, Recover);
+  return new HWAddressSanitizerLegacyPass(CompileKernel, Recover, TargetTriple);
 }
 
-HWAddressSanitizerPass::HWAddressSanitizerPass(bool CompileKernel, bool Recover)
-    : CompileKernel(CompileKernel), Recover(Recover) {}
+HWAddressSanitizerPass::HWAddressSanitizerPass(bool CompileKernel, bool Recover,
+                                               Triple TargetTriple)
+    : CompileKernel(CompileKernel), Recover(Recover),
+      TargetTriple(TargetTriple) {}
 
 PreservedAnalyses HWAddressSanitizerPass::run(Module &M,
                                               ModuleAnalysisManager &MAM) {
-  HWAddressSanitizer HWASan(M, CompileKernel, Recover);
+  const StackSafetyGlobalInfo *SSI = nullptr;
+  if (shouldUseStackSafetyAnalysis(TargetTriple)) {
+    SSI = &MAM.getResult<StackSafetyGlobalAnalysis>(M);
+  }
+  HWAddressSanitizer HWASan(M, CompileKernel, Recover, SSI);
   bool Modified = false;
   for (Function &F : M)
     Modified |= HWASan.sanitizeFunction(F);
@@ -503,9 +552,9 @@
   // - Intel LAM (default)
   // - pointer aliasing (heap only)
   bool IsX86_64 = TargetTriple.getArch() == Triple::x86_64;
-  UsePageAliases = ClUsePageAliases && IsX86_64;
+  UsePageAliases = shouldUsePageAliases(TargetTriple);
   InstrumentWithCalls = IsX86_64 ? true : ClInstrumentWithCalls;
-  InstrumentStack = UsePageAliases ? false : ClInstrumentStack;
+  InstrumentStack = shouldInstrumentStack(TargetTriple);
   PointerTagShift = IsX86_64 ? 57 : 56;
   TagMaskByte = IsX86_64 ? 0x3F : 0xFF;
 
@@ -1223,6 +1272,7 @@
 }
 
 bool HWAddressSanitizer::isInterestingAlloca(const AllocaInst &AI) {
+  // clang-format off
   return (AI.getAllocatedType()->isSized() &&
           // FIXME: instrument dynamic allocas, too
           AI.isStaticAlloca() &&
@@ -1235,7 +1285,10 @@
           // dynamic alloca instrumentation for them as well.
           !AI.isUsedWithInAlloca() &&
           // swifterror allocas are register promoted by ISel
-          !AI.isSwiftError());
+          !AI.isSwiftError()) &&
+          // safe allocas are not interesting
+          !(SSI && SSI->isSafe(AI));
+  // clang-format on
 }
 
 bool HWAddressSanitizer::sanitizeFunction(Function &F) {
Index: llvm/include/llvm/Transforms/Instrumentation/HWAddressSanitizer.h
===================================================================
--- llvm/include/llvm/Transforms/Instrumentation/HWAddressSanitizer.h
+++ llvm/include/llvm/Transforms/Instrumentation/HWAddressSanitizer.h
@@ -14,6 +14,8 @@
 #ifndef LLVM_TRANSFORMS_INSTRUMENTATION_HWADDRESSSANITIZER_H
 #define LLVM_TRANSFORMS_INSTRUMENTATION_HWADDRESSSANITIZER_H
 
+#include "llvm/ADT/Triple.h"
+
 #include "llvm/IR/Function.h"
 #include "llvm/IR/PassManager.h"
 
@@ -25,17 +27,20 @@
 class HWAddressSanitizerPass : public PassInfoMixin<HWAddressSanitizerPass> {
 public:
   explicit HWAddressSanitizerPass(bool CompileKernel = false,
-                                  bool Recover = false);
+                                  bool Recover = false,
+                                  Triple TargetTriple = {});
   PreservedAnalyses run(Module &M, ModuleAnalysisManager &MAM);
   static bool isRequired() { return true; }
 
 private:
   bool CompileKernel;
   bool Recover;
+  Triple TargetTriple;
 };
 
 FunctionPass *createHWAddressSanitizerLegacyPassPass(bool CompileKernel = false,
-                                                     bool Recover = false);
+                                                     bool Recover = false,
+                                                     Triple TargetTriple = {});
 
 namespace HWASanAccessInfo {
 
Index: clang/test/CodeGen/hwasan-stack-safety-analysis.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/hwasan-stack-safety-analysis.c
@@ -0,0 +1,11 @@
+// RUN: %clang -fsanitize=hwaddress -target aarch64-linux-gnu -S -emit-llvm -mllvm -hwasan-use-stack-safety=true -mllvm -hwasan-generate-tags-with-calls -O2 %s -o - | FileCheck %s --check-prefix=SAFETY
+// RUN: %clang -fsanitize=hwaddress -target aarch64-linux-gnu -S -emit-llvm -mllvm -hwasan-use-stack-safety=false -mllvm -hwasan-generate-tags-with-calls -O2 %s -o - | FileCheck %s --check-prefix=NOSAFETY
+
+int main(int argc, char **argv) {
+  char buf[10];
+  volatile char *x = buf;
+  *x = 0;
+  return buf[0];
+  // NOSAFETY: __hwasan_generate_tag
+  // SAFETY-NOT: __hwasan_generate_tag
+}
Index: clang/test/CodeGen/hwasan-stack-safety-analysis-asm.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/hwasan-stack-safety-analysis-asm.c
@@ -0,0 +1,11 @@
+// RUN: %clang -fsanitize=hwaddress -target aarch64-linux-gnu -S -mllvm -hwasan-use-stack-safety=true -mllvm -hwasan-generate-tags-with-calls -O2 %s -o - | FileCheck %s --check-prefix=SAFETY
+// RUN: %clang -fsanitize=hwaddress -target aarch64-linux-gnu -S -mllvm -hwasan-use-stack-safety=false -mllvm -hwasan-generate-tags-with-calls -O2 %s -o - | FileCheck %s --check-prefix=NOSAFETY
+
+int main(int argc, char **argv) {
+  char buf[10];
+  volatile char *x = buf;
+  *x = 0;
+  return buf[0];
+  // NOSAFETY: __hwasan_generate_tag
+  // SAFETY-NOT: __hwasan_generate_tag
+}
Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -314,14 +314,17 @@
       static_cast<const PassManagerBuilderWrapper &>(Builder);
   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::HWAddress);
-  PM.add(
-      createHWAddressSanitizerLegacyPassPass(/*CompileKernel*/ false, Recover));
+  PM.add(createHWAddressSanitizerLegacyPassPass(
+      /*CompileKernel*/ false, Recover, BuilderWrapper.getTargetTriple()));
 }
 
 static void addKernelHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
                                             legacy::PassManagerBase &PM) {
+  const PassManagerBuilderWrapper &BuilderWrapper =
+      static_cast<const PassManagerBuilderWrapper &>(Builder);
   PM.add(createHWAddressSanitizerLegacyPassPass(
-      /*CompileKernel*/ true, /*Recover*/ true));
+      /*CompileKernel*/ true, /*Recover*/ true,
+      BuilderWrapper.getTargetTriple()));
 }
 
 static void addGeneralOptsForMemorySanitizer(const PassManagerBuilder &Builder,
@@ -1164,7 +1167,8 @@
     auto HWASanPass = [&](SanitizerMask Mask, bool CompileKernel) {
       if (LangOpts.Sanitize.has(Mask)) {
         bool Recover = CodeGenOpts.SanitizeRecover.has(Mask);
-        MPM.addPass(HWAddressSanitizerPass(CompileKernel, Recover));
+        MPM.addPass(
+            HWAddressSanitizerPass(CompileKernel, Recover, TargetTriple));
       }
     };
     HWASanPass(SanitizerKind::HWAddress, false);
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