[HWASAN] Don't instrument loads from global if globals are not tagged

[vitalybuka]

No description provided.

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Vitaly Buka (vitalybuka)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/86774.diff

3 Files Affected:

• (modified) llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp (+8)
• (modified) llvm/test/Instrumentation/HWAddressSanitizer/globals-access.ll (-16)
• (modified) llvm/test/Instrumentation/HWAddressSanitizer/use-after-scope-setjmp.ll (-1)

diff --git a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
index 96fd530be33318..f89a22d951a9f7 100644
--- a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -790,6 +790,14 @@ bool HWAddressSanitizer::ignoreAccess(Instruction *Inst, Value *Ptr) {
     if (SSI && SSI->stackAccessIsSafe(*Inst))
       return true;
   }
+
+  GlobalVariable *G = dyn_cast<GlobalVariable>(getUnderlyingObject(Ptr));
+  if (G) {
+    if (!InstrumentGlobals)
+      return true;
+    // TODO: Optimize inbound global accesses, like Asan `instrumentMop`.
+  }
+
   return false;
 }
 
diff --git a/llvm/test/Instrumentation/HWAddressSanitizer/globals-access.ll b/llvm/test/Instrumentation/HWAddressSanitizer/globals-access.ll
index e59701253d8bc1..11ac88c40c2ed6 100644
--- a/llvm/test/Instrumentation/HWAddressSanitizer/globals-access.ll
+++ b/llvm/test/Instrumentation/HWAddressSanitizer/globals-access.ll
@@ -13,22 +13,6 @@ define dso_local noundef i32 @_Z3tmpv() sanitize_hwaddress {
 ; OFF-LABEL: define dso_local noundef i32 @_Z3tmpv(
 ; OFF-SAME: ) #[[ATTR0:[0-9]+]] {
 ; OFF-NEXT:  entry:
-; OFF-NEXT:    [[TMP12:%.*]] = load i64, ptr @__hwasan_tls, align 8
-; OFF-NEXT:    [[TMP1:%.*]] = or i64 [[TMP12]], 4294967295
-; OFF-NEXT:    [[HWASAN_SHADOW:%.*]] = add i64 [[TMP1]], 1
-; OFF-NEXT:    [[TMP2:%.*]] = inttoptr i64 [[HWASAN_SHADOW]] to ptr
-; OFF-NEXT:    [[TMP3:%.*]] = lshr i64 ptrtoint (ptr @x to i64), 56
-; OFF-NEXT:    [[TMP4:%.*]] = trunc i64 [[TMP3]] to i8
-; OFF-NEXT:    [[TMP5:%.*]] = and i64 ptrtoint (ptr @x to i64), 72057594037927935
-; OFF-NEXT:    [[TMP6:%.*]] = lshr i64 [[TMP5]], 4
-; OFF-NEXT:    [[TMP7:%.*]] = getelementptr i8, ptr [[TMP2]], i64 [[TMP6]]
-; OFF-NEXT:    [[TMP8:%.*]] = load i8, ptr [[TMP7]], align 1
-; OFF-NEXT:    [[TMP9:%.*]] = icmp ne i8 [[TMP4]], [[TMP8]]
-; OFF-NEXT:    br i1 [[TMP9]], label [[TMP10:%.*]], label [[TMP11:%.*]], !prof [[PROF1:![0-9]+]]
-; OFF:       10:
-; OFF-NEXT:    call void @llvm.hwasan.check.memaccess.shortgranules(ptr [[TMP2]], ptr @x, i32 2)
-; OFF-NEXT:    br label [[TMP11]]
-; OFF:       11:
 ; OFF-NEXT:    [[TMP0:%.*]] = load i32, ptr @x, align 4
 ; OFF-NEXT:    ret i32 [[TMP0]]
 ;
diff --git a/llvm/test/Instrumentation/HWAddressSanitizer/use-after-scope-setjmp.ll b/llvm/test/Instrumentation/HWAddressSanitizer/use-after-scope-setjmp.ll
index 079d7224128301..62fd7a16715693 100644
--- a/llvm/test/Instrumentation/HWAddressSanitizer/use-after-scope-setjmp.ll
+++ b/llvm/test/Instrumentation/HWAddressSanitizer/use-after-scope-setjmp.ll
@@ -54,7 +54,6 @@ define dso_local noundef i1 @_Z6targetv() sanitize_hwaddress {
 ; CHECK:       sw.bb1:
 ; CHECK-NEXT:    br label [[RETURN]]
 ; CHECK:       while.body:
-; CHECK-NEXT:    call void @llvm.hwasan.check.memaccess(ptr [[TMP16]], ptr @stackbuf, i32 19)
 ; CHECK-NEXT:    store ptr [[BUF_HWASAN]], ptr @stackbuf, align 8
 ; CHECK-NEXT:    call void @may_jump()
 ; CHECK-NEXT:    br label [[RETURN]]