Subzero: Improved quality of ASan error messages

tests_lit/asan_tests/wideloads.ll

 ; Test that potentially widened loads to not trigger an error report
 
 ; REQUIRES: no_minimal_build
 
 ; check for wide load exception
 ; RUN: llvm-as %s -o - | pnacl-freeze > %t.pexe && %S/../../pydir/szbuild.py \
 ; RUN:     --fsanitize-address --sz=-allow-externally-defined-symbols \
 ; RUN:     %t.pexe -o %t && %t | FileCheck %s --check-prefix=WIDE --allow-empty
 
 ; check for error reporting
@@ skipping 15 matching lines @@
 define internal void @no_wide_load() {
   %str = alloca i8, i32 1, align 1
   %straddr = ptrtoint i8* %str to i32
   %off1addr = add i32 %straddr, 1
   %off1 = inttoptr i32 %off1addr to i8*
   %contents = load i8, i8* %off1, align 1
   call void @exit(i32 1) 
   unreachable
 }
 
-; WIDE-NOT: Illegal access
-; NOWIDE: Illegal access of 1 bytes at
+; WIDE-NOT: Illegal
+; NOWIDE: Illegal 1 byte load from stack object at
 
 ; use argc to determine which test routine to run
 define void @_start(i32 %arg) {
   %argcaddr = add i32 %arg, 8
   %argcptr = inttoptr i32 %argcaddr to i32*
   %argc = load i32, i32* %argcptr, align 1
   switch i32 %argc, label %error [i32 1, label %wide_load
                                   i32 2, label %no_wide_load]
 wide_load:
   call void @wide_load()
   br label %error
 no_wide_load:
   call void @no_wide_load()
   br label %error
 error:
   call void @exit(i32 1)
   unreachable
 }