[PATCH] D105201: [hwasan] Detect use after scope within function.

[Vitaly Buka via Phabricator via llvm-commits]

vitalybuka accepted this revision.
vitalybuka added a comment.
This revision is now accepted and ready to land.

LGTM if you improve the test



================
Comment at: llvm/test/Instrumentation/HWAddressSanitizer/use-after-scope.ll:9
+
+define dso_local i32 @main() local_unnamed_addr sanitize_hwaddress {
+  %1 = alloca i8, align 1
----------------
this tests StandardLifetime && forAllReachableExits
but it would be nice to have these cases:
StandardLifetime && !forAllReachableExits
!StandardLifetime

also depending on conditions above we may keep or remove lifetime markers.
So we need to test 
could you please add corresponding CHECKs here?

to my taste the following produces good enough result, but I don't ask to switch to auto-generated tests. It's your call.
llvm/utils/update_test_checks.py --opt-binary <build_dir>/bin/opt llvm/test/Instrumentation/HWAddressSanitizer/use-after-scope.ll


```
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -hwasan -hwasan-use-after-scope=1 -hwasan-generate-tags-with-calls -S < %s | FileCheck %s --check-prefixes=SCOPE
; RUN: opt -hwasan -hwasan-use-after-scope=0 -hwasan-generate-tags-with-calls -S < %s | FileCheck %s --check-prefixes=NOSCOPE

; ModuleID = 'use-after-scope.c'
source_filename = "use-after-scope.c"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

define dso_local i32 @main() local_unnamed_addr sanitize_hwaddress {
; SCOPE-LABEL: @main(
; SCOPE-NEXT:    [[DOTHWASAN_SHADOW:%.*]] = call i8* asm "", "=r,0"(i8* null)
; SCOPE-NEXT:    [[TMP1:%.*]] = alloca { i8, [15 x i8] }, align 16
; SCOPE-NEXT:    [[TMP2:%.*]] = bitcast { i8, [15 x i8] }* [[TMP1]] to i8*
; SCOPE-NEXT:    [[TMP3:%.*]] = call i8 @__hwasan_generate_tag()
; SCOPE-NEXT:    [[TMP4:%.*]] = zext i8 [[TMP3]] to i64
; SCOPE-NEXT:    [[TMP5:%.*]] = ptrtoint i8* [[TMP2]] to i64
; SCOPE-NEXT:    [[TMP6:%.*]] = shl i64 [[TMP4]], 57
; SCOPE-NEXT:    [[TMP7:%.*]] = or i64 [[TMP5]], [[TMP6]]
; SCOPE-NEXT:    [[ALLOCA_0_HWASAN:%.*]] = inttoptr i64 [[TMP7]] to i8*
; SCOPE-NEXT:    br label [[TMP8:%.*]]
; SCOPE:       8:
; SCOPE-NEXT:    call void @llvm.lifetime.start.p0i8(i64 1, i8* nonnull [[ALLOCA_0_HWASAN]])
; SCOPE-NEXT:    [[TMP9:%.*]] = trunc i64 [[TMP4]] to i8
; SCOPE-NEXT:    call void @__hwasan_tag_memory(i8* [[TMP2]], i8 [[TMP9]], i64 16)
; SCOPE-NEXT:    [[TMP10:%.*]] = tail call i32 (...) @cond()
; SCOPE-NEXT:    [[TMP11:%.*]] = icmp eq i32 [[TMP10]], 0
; SCOPE-NEXT:    call void @__hwasan_tag_memory(i8* [[TMP2]], i8 0, i64 16)
; SCOPE-NEXT:    call void @llvm.lifetime.end.p0i8(i64 1, i8* nonnull [[ALLOCA_0_HWASAN]])
; SCOPE-NEXT:    br i1 [[TMP11]], label [[TMP12:%.*]], label [[TMP8]]
; SCOPE:       12:
; SCOPE-NEXT:    call void @use(i8* nonnull [[ALLOCA_0_HWASAN]])
; SCOPE-NEXT:    ret i32 0
;
; NOSCOPE-LABEL: @main(
; NOSCOPE-NEXT:    [[DOTHWASAN_SHADOW:%.*]] = call i8* asm "", "=r,0"(i8* null)
; NOSCOPE-NEXT:    [[TMP1:%.*]] = alloca { i8, [15 x i8] }, align 16
; NOSCOPE-NEXT:    [[TMP2:%.*]] = bitcast { i8, [15 x i8] }* [[TMP1]] to i8*
; NOSCOPE-NEXT:    [[TMP3:%.*]] = call i8 @__hwasan_generate_tag()
; NOSCOPE-NEXT:    [[TMP4:%.*]] = zext i8 [[TMP3]] to i64
; NOSCOPE-NEXT:    [[TMP5:%.*]] = ptrtoint i8* [[TMP2]] to i64
; NOSCOPE-NEXT:    [[TMP6:%.*]] = shl i64 [[TMP4]], 57
; NOSCOPE-NEXT:    [[TMP7:%.*]] = or i64 [[TMP5]], [[TMP6]]
; NOSCOPE-NEXT:    [[ALLOCA_0_HWASAN:%.*]] = inttoptr i64 [[TMP7]] to i8*
; NOSCOPE-NEXT:    [[TMP8:%.*]] = trunc i64 [[TMP4]] to i8
; NOSCOPE-NEXT:    call void @__hwasan_tag_memory(i8* [[TMP2]], i8 [[TMP8]], i64 16)
; NOSCOPE-NEXT:    br label [[TMP9:%.*]]
; NOSCOPE:       9:
; NOSCOPE-NEXT:    call void @llvm.lifetime.start.p0i8(i64 1, i8* nonnull [[ALLOCA_0_HWASAN]])
; NOSCOPE-NEXT:    [[TMP10:%.*]] = tail call i32 (...) @cond()
; NOSCOPE-NEXT:    [[TMP11:%.*]] = icmp eq i32 [[TMP10]], 0
; NOSCOPE-NEXT:    call void @llvm.lifetime.end.p0i8(i64 1, i8* nonnull [[ALLOCA_0_HWASAN]])
; NOSCOPE-NEXT:    br i1 [[TMP11]], label [[TMP12:%.*]], label [[TMP9]]
; NOSCOPE:       12:
; NOSCOPE-NEXT:    call void @use(i8* nonnull [[ALLOCA_0_HWASAN]])
; NOSCOPE-NEXT:    call void @__hwasan_tag_memory(i8* [[TMP2]], i8 0, i64 16)
; NOSCOPE-NEXT:    ret i32 0
;
  %1 = alloca i8, align 1
  br label %2

2:                                                ; preds = %2, %0
; We should tag the memory after the br (in the loop).
  call void @llvm.lifetime.start.p0i8(i64 1, i8* nonnull %1)
  %3 = tail call i32 (...) @cond() #2
  %4 = icmp eq i32 %3, 0
; We should tag the memory before the next br (before the jump back).
  call void @llvm.lifetime.end.p0i8(i64 1, i8* nonnull %1)
  br i1 %4, label %5, label %2

5:                                                ; preds = %2
  call void @use(i8* nonnull %1) #2
  ret i32 0
}

declare dso_local i32 @cond(...) local_unnamed_addr

declare dso_local void @use(i8*) local_unnamed_addr

; Function Attrs: argmemonly mustprogress nofree nosync nounwind willreturn
declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture)

; Function Attrs: argmemonly mustprogress nofree nosync nounwind willreturn
declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture)
```


================
Comment at: llvm/test/Instrumentation/HWAddressSanitizer/use-after-scope.ll:44
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture)
\ No newline at end of file

----------------
please add new line


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