Fix prologue detection for PNaCl.

Fix prologue detection for PNaCl.

Recognize mov %ebp,%reg // push %reg sequence as push %rbp to detect
prologue in PNaCl code.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3600
TEST= None
R=eaeltsin@google.com

Committed: https://git.chromium.org/gitweb?p=native_client/nacl-gdb.git;a=commit;h=4b05a39

[eaeltsin, 2013-08-07 17:58:50]

lgtm

But please fix style and add comments as asked below.

https://codereview.chromium.org/22393004/diff/4001/gdb/amd64-tdep.c
File gdb/amd64-tdep.c (right):

https://codereview.chromium.org/22393004/diff/4001/gdb/amd64-tdep.c#newcode2047
gdb/amd64-tdep.c:2047: +   size of instruction or zero if it is not recognized. 
*/
Comment that you also set 'reg'.

https://codereview.chromium.org/22393004/diff/4001/gdb/amd64-tdep.c#newcode2054
gdb/amd64-tdep.c:2054: +    {
It would be nice if you add a comment with a sample assembler insn with
encoding. Ditto below.

https://codereview.chromium.org/22393004/diff/4001/gdb/amd64-tdep.c#newcode2055
gdb/amd64-tdep.c:2055: +      cur ++;
Do you need whitespace between cur and ++? Ditto below.

https://codereview.chromium.org/22393004/diff/4001/gdb/amd64-tdep.c#newcode2086
gdb/amd64-tdep.c:2086: +  read_memory(pc, op, 5);
Though unlikely, you might encounter the case when you can't read 5 bytes from
the pc, for example, a function that has just 'ret' inside and is last in
.text...

How similar gdb functions handle this? Just ignore?

https://codereview.chromium.org/22393004/diff/4001/gdb/amd64-tdep.c#newcode2087
gdb/amd64-tdep.c:2087: +  if (op[0] == 0x55)
Ditto here and below.

Add a comment like
  /* 55 push %rbp  */

https://codereview.chromium.org/22393004/diff/4001/gdb/amd64-tdep.c#newcode2142
gdb/amd64-tdep.c:2142: +  int is_push_rbp;
I'd rename this to push_rbp_size

[halyavin, 2013-08-08 06:23:25]

Committed patchset #3 manually as r4b05a39 (presubmit successful).