Update PNaCl to LLVM/Clang/Libcxx 223109 (nacl-change)

tools/toolchain_tester/known_failures_pnacl.txt

 # Copyright (c) 2013 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # NOTE:
 # progress on eliminating failures here should be recorded via
 # http://code.google.com/p/nativeclient/issues/detail?id=2204
 # ======================================================================
 # failures in phase sel_ldr
 # ======================================================================
@@ skipping 92 matching lines @@
 pr23135.c
 # asm - invalid output constraint =t (is apparently undocumented in gcc)
 990413-2.c
 # <scumbagsteve> implicit return type int
 # does not return a value </scumbagsteve> (error only in clang)
 920728-1.c
 # __builtin_nan result is not a compile-time constant
 builtin-nan-1.c
 # __builtin_apply and friends not supported by clang
 pr47237.c
+# This test has an integer overflow / undefined behavior:
+20031003-1.c

[JF, 2015/02/23 21:50:43]

What fails in the test?

[jvoung (off chromium), 2015/02/23 22:12:00]

The test does:

int f1()
{
  return (int)2147483648.0f;
}

and expects f1() == 2147483647

I thought this was undefined behavior when the integral part of the float cannot
be represented by "int".

[JF, 2015/02/23 22:39:46]

Right, this is UB. Even with vanilla clang we get:

int f1()
{
  400530:	55                   	push   %rbp
  400531:	48 89 e5             	mov    %rsp,%rbp
  return (int)2147483648.0f;
  400534:	5d                   	pop    %rbp
  400535:	c3                   	retq   
  400536:	66 2e 0f 1f 84 00 00 	nopw   %cs:0x0(%rax,%rax,1)
  40053d:	00 00 00 

Compiling with -emit-after-all shows that clang generates the following IR:

define i32 @f1() #0 {
entry:
  ret i32 undef, !dbg !16
}

From the discussions on the GCC mailing list it sounds like some people fixed
the UB for their platform, but not in general... Meh.

 # ======================================================================
 # wont fixes - nested functions
 # ======================================================================
 # nested function
 nest-align-1.c
 # nested function
 nest-stdar-1.c
 # nested function
 nestfunc-7.c
 # nested function
@@ skipping 43 matching lines @@
 # complex va_arg
 stdarg-3.c
 # complex va_arg
 strct-stdarg-1.c
 # complex va_arg
 strct-varg-1.c
 # complex va_arg
 va-arg-22.c
 # complex va_arg
 pr44575.c