Fix ARM .p2align implementation
Nick Clifton
nickc@cambridge.redhat.com
Sun May 6 03:10:00 GMT 2001
Hi Guys,
Oops - just discovered a bug in my recent implementation of no-op
padding for the .p2align directive. I was not checking to see how
many padding bytes needed to be inserted, and it was possible to
overrun the buffer in the frag. The patch below fixes this, and
also switches the use of 'fragp' to 'fragP' to match the convention
use din the rest of the file.
Cheers
Nick
2001-05-06 Nick Clifton <nickc@cambridge.redhat.com>
* config/tc-arm.h (MAX_MEM_FOR_RS_ALIGN_CODE): Define.
* config/tc-arm.c (arm_handle_align): Do not insert more than
MAX_MEM_FOR_RS_ALIGN_CODE bytes.
(arm_frag_align_code): Use MAX_MEM_FOR_RS_ALIGN_CODE.
Index: config/tc-arm.h
===================================================================
RCS file: /cvs/src/src/gas/config/tc-arm.h,v
retrieving revision 1.13
diff -p -r1.13 tc-arm.h
*** tc-arm.h 2001/04/26 15:19:21 1.13
--- tc-arm.h 2001/05/06 10:08:38
*************** void armelf_frob_symbol PARAMS ((symbolS
*** 215,220 ****
--- 215,222 ----
#define DWARF2_LINE_MIN_INSN_LENGTH 2
#endif
+ #define MAX_MEM_FOR_RS_ALIGN_CODE 31
+
/* For frags in code sections we need to record whether they contain
ARM code or THUMB code. This is that if they have to be aligned,
they can contain the correct type of no-op instruction. */
Index: config/tc-arm.c
===================================================================
RCS file: /cvs/src/src/gas/config/tc-arm.c,v
retrieving revision 1.81
diff -p -r1.81 tc-arm.c
*** tc-arm.c 2001/05/02 18:40:10 1.81
--- tc-arm.c 2001/05/06 10:08:38
*************** s_arm_elf_cons (nbytes)
*** 8796,8803 ****
of an rs_align_code fragment. */
void
! arm_handle_align (fragp)
! fragS *fragp;
{
static char const arm_noop[4] = { 0x00, 0x00, 0xa0, 0xe1 };
static char const thumb_noop[2] = { 0xc0, 0x46 };
--- 8796,8803 ----
of an rs_align_code fragment. */
void
! arm_handle_align (fragP)
! fragS *fragP;
{
static char const arm_noop[4] = { 0x00, 0x00, 0xa0, 0xe1 };
static char const thumb_noop[2] = { 0xc0, 0x46 };
*************** arm_handle_align (fragp)
*** 8808,8821 ****
char * p;
const char * noop;
! if (fragp->fr_type != rs_align_code)
return;
! bytes = fragp->fr_next->fr_address - fragp->fr_address - fragp->fr_fix;
! p = fragp->fr_literal + fragp->fr_fix;
fix = 0;
! if (fragp->tc_frag_data)
{
if (target_big_endian)
noop = thumb_bigend_noop;
--- 8808,8824 ----
char * p;
const char * noop;
! if (fragP->fr_type != rs_align_code)
return;
! bytes = fragP->fr_next->fr_address - fragP->fr_address - fragP->fr_fix;
! p = fragP->fr_literal + fragP->fr_fix;
fix = 0;
! if (bytes > MAX_MEM_FOR_RS_ALIGN_CODE)
! bytes = MAX_MEM_FOR_RS_ALIGN_CODE;
!
! if (fragP->tc_frag_data)
{
if (target_big_endian)
noop = thumb_bigend_noop;
*************** arm_handle_align (fragp)
*** 8848,8855 ****
fix += noop_size;
}
! fragp->fr_fix += fix;
! fragp->fr_var = noop_size;
}
/* Called from md_do_align. Used to create an alignment
--- 8851,8858 ----
fix += noop_size;
}
! fragP->fr_fix += fix;
! fragP->fr_var = noop_size;
}
/* Called from md_do_align. Used to create an alignment
*************** arm_frag_align_code (n, max)
*** 8864,8874 ****
/* We assume that there will never be a requirment
to support alignments greater than 32 bytes. */
! if (max > 31)
as_fatal (_("alignments greater than 32 bytes not supported in .text sections."));
p = frag_var (rs_align_code,
! 31,
1,
(relax_substateT) max,
(symbolS *) NULL,
--- 8867,8877 ----
/* We assume that there will never be a requirment
to support alignments greater than 32 bytes. */
! if (max > MAX_MEM_FOR_RS_ALIGN_CODE)
as_fatal (_("alignments greater than 32 bytes not supported in .text sections."));
p = frag_var (rs_align_code,
! MAX_MEM_FOR_RS_ALIGN_CODE,
1,
(relax_substateT) max,
(symbolS *) NULL,
*************** arm_frag_align_code (n, max)
*** 8881,8889 ****
/* Perform target specific initialisation of a frag. */
void
! arm_init_frag (fragp)
! fragS *fragp;
{
/* Record whether this frag is in an ARM or a THUMB area. */
! fragp->tc_frag_data = thumb_mode;
}
--- 8884,8892 ----
/* Perform target specific initialisation of a frag. */
void
! arm_init_frag (fragP)
! fragS *fragP;
{
/* Record whether this frag is in an ARM or a THUMB area. */
! fragP->tc_frag_data = thumb_mode;
}
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