[LLVMbugs] [Bug 3935] Invalid addresses at compile time not diagnosed

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=3935

Kaelyn Uhrain <rikka at google.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |rikka at google.com
         Resolution|                            |FIXED

--- Comment #1 from Kaelyn Uhrain <rikka at google.com> 2012-06-21 16:22:37 CDT ---
Since at least the 3.1 release, clang will warn about the invalid array index
via -Warray-bounds, which is enabled by default:

$ cat tmp.cc 
int x[2], *y = &x[3], *z = x + 3;

$ clang -fsyntax-only tmp.cc
tmp.cc:1:17: warning: array index 3 is past the end of the array (which
contains 2 elements)
      [-Warray-bounds]
int x[2], *y = &x[3], *z = x + 3;
                ^ ~
tmp.cc:1:1: note: array 'x' declared here
int x[2], *y = &x[3], *z = x + 3;
^
1 warning generated.


Additionally, passing -Warray-bounds-pointer-arithmetic will also raise a
warning about the bad pointer arithmetic:

$ clang -fsyntax-only -Warray-bounds-pointer-arithmetic -Wno-array-bounds
tmp.cc           
tmp.cc:1:28: warning: the pointer incremented by 3 refers past the end of the
array
      (that contains 2 elements) [-Warray-bounds-pointer-arithmetic]
int x[2], *y = &x[3], *z = x + 3;
                           ^   ~
tmp.cc:1:1: note: array 'x' declared here
int x[2], *y = &x[3], *z = x + 3;
^
1 warning generated.

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