A few fixes for ARMv5TE.

runtime/vm/os_linux.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_OS_LINUX)
 
 #include "vm/os.h"
 
 #include <errno.h>  // NOLINT
@@ skipping 489 matching lines @@
     ASSERT(errno == EINTR);
     // Copy remainder into requested and repeat.
     req = rem;
   }
 }
 
 
 void OS::DebugBreak() {
 #if defined(HOST_ARCH_X64) || defined(HOST_ARCH_IA32)
   asm("int $3");
-#elif defined(HOST_ARCH_ARM)
+#elif defined(HOST_ARCH_ARM) && !defined(__THUMBEL__)
   asm("svc #0x9f0001");  // __ARM_NR_breakpoint

[zra, 2015/03/30 17:25:00]

This is not a valid thumb instruction.

[srdjan, 2015/03/30 17:39:50]

Is there a breakpoint instruction in thumb instruction set?

[zra, 2015/03/30 20:02:05]

After cleanup, only the Intel instruction should be needed.

+#elif defined(HOST_ARCH_ARM) && defined(__THUMBEL__)
+  UNIMPLEMENTED();
 #elif defined(HOST_ARCH_MIPS) || defined(HOST_ARCH_ARM64)
   UNIMPLEMENTED();

[regis, 2015/03/30 18:12:43]

I am wondering how you figured out that this instruction was not available on
Thumb, since we only call this OS::DebugBreak() from the simulator to enter gdb
on Intel platforms.
As Srdjan indicates, an UNIMPLEMENTED is not really solving the problem. On the
other hand, there is no problem to solve so far :-)

Apparently, this is also called from a vm test "CodeImmutability", which I do
not understand.

I think some TODOs to remember to clean up this mess would be good.

[zra, 2015/03/30 20:02:05]

gcc refuses to compile the inline assembly if you pass -mthumb.
TODO added.

 #else
 #error Unsupported architecture.
 #endif
 }
 
 
 char* OS::StrNDup(const char* s, intptr_t n) {
   return strndup(s, n);
 }
 
@@ skipping 92 matching lines @@
 }
 
 
 void OS::Exit(int code) {
   exit(code);
 }
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)