r197362 - Stop crashing on empty asm input constraints

[Duncan P. N. Exon Smith]

Author: dexonsmith
Date: Sun Dec 15 21:20:06 2013
New Revision: 197362

URL: http://llvm.org/viewvc/llvm-project?rev=197362&view=rev
Log:
Stop crashing on empty asm input constraints

An empty string for an ASM input constraint is invalid, and will crash
during clang CodeGen.  Change TargetInfo::validateInputConstraint to
reject an empty string.

<rdar://problem/15552191>

Modified:
    cfe/trunk/lib/Basic/TargetInfo.cpp
    cfe/trunk/test/Sema/asm.c

Modified: cfe/trunk/lib/Basic/TargetInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/TargetInfo.cpp?rev=197362&r1=197361&r2=197362&view=diff
==============================================================================
--- cfe/trunk/lib/Basic/TargetInfo.cpp (original)
+++ cfe/trunk/lib/Basic/TargetInfo.cpp Sun Dec 15 21:20:06 2013
@@ -482,6 +482,9 @@ bool TargetInfo::validateInputConstraint
                                          ConstraintInfo &Info) const {
   const char *Name = Info.ConstraintStr.c_str();
 
+  if (!*Name)
+    return false;
+
   while (*Name) {
     switch (*Name) {
     default:

Modified: cfe/trunk/test/Sema/asm.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/asm.c?rev=197362&r1=197361&r2=197362&view=diff
==============================================================================
--- cfe/trunk/test/Sema/asm.c (original)
+++ cfe/trunk/test/Sema/asm.c Sun Dec 15 21:20:06 2013
@@ -13,6 +13,9 @@ void f() {
   asm ("foo\n" : "=a" (i) : "[" (i)); // expected-error {{invalid input constraint '[' in asm}}
   asm ("foo\n" : "=a" (i) : "[foo" (i)); // expected-error {{invalid input constraint '[foo' in asm}}
   asm ("foo\n" : "=a" (i) : "[symbolic_name]" (i)); // expected-error {{invalid input constraint '[symbolic_name]' in asm}}
+
+  asm ("foo\n" : : "" (i)); // expected-error {{invalid input constraint '' in asm}}
+  asm ("foo\n" : "=a" (i) : "" (i)); // expected-error {{invalid input constraint '' in asm}}
 }
 
 void clobbers() {