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MIPS: Make the extracted stack offset signed in the prologue scanner

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Make the extracted stack offset signed in the standard MIPS prologue
scanner, to simplify handling and make sure register offsets are correct
in all cases, especially where $fp equals the virtual frame pointer (old
GCC frames) and therefore offsets to save slots are negative.

	* mips-tdep.c (mips32_scan_prologue): Make the extracted stack
	offset signed.
This commit is contained in:
Maciej W. Rozycki 2015-01-02 23:36:05 +00:00
parent 0300bbc7c5
commit eaa6a9a482
2 changed files with 16 additions and 10 deletions
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5
gdb/ChangeLog
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@ -1,3 +1,8 @@
2015-01-02 Maciej W. Rozycki <macro@codesourcery.com>
* mips-tdep.c (mips32_scan_prologue): Keep the extracted stack
offset signed.
2015-01-02 Doug Evans <dje@google.com>
* dwarf2read.c (setup_type_unit_groups): Remove outdated comment.

21
gdb/mips-tdep.c
View file

@ -3438,7 +3438,8 @@ restart:
frame_offset = 0;
for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += MIPS_INSN32_SIZE)
{
unsigned long inst, high_word, low_word;
unsigned long inst, high_word;
long offset;
int reg;
this_non_prologue_insn = 0;
@ -3450,15 +3451,15 @@ restart:
/* Save some code by pre-extracting some useful fields. */
high_word = (inst >> 16) & 0xffff;
low_word = inst & 0xffff;
offset = ((inst & 0xffff) ^ 0x8000) - 0x8000;
reg = high_word & 0x1f;
if (high_word == 0x27bd /* addiu $sp,$sp,-i */
|| high_word == 0x23bd /* addi $sp,$sp,-i */
|| high_word == 0x67bd) /* daddiu $sp,$sp,-i */
{
if (low_word & 0x8000) /* Negative stack adjustment? */
frame_offset += 0x10000 - low_word;
if (offset < 0) /* Negative stack adjustment? */
frame_offset -= offset;
else
/* Exit loop if a positive stack adjustment is found, which
usually means that the stack cleanup code in the function
@ -3469,19 +3470,19 @@ restart:
else if (((high_word & 0xFFE0) == 0xafa0) /* sw reg,offset($sp) */
&& !regsize_is_64_bits)
{
set_reg_offset (gdbarch, this_cache, reg, sp + low_word);
set_reg_offset (gdbarch, this_cache, reg, sp + offset);
}
else if (((high_word & 0xFFE0) == 0xffa0) /* sd reg,offset($sp) */
&& regsize_is_64_bits)
{
/* Irix 6.2 N32 ABI uses sd instructions for saving $gp and $ra. */
set_reg_offset (gdbarch, this_cache, reg, sp + low_word);
set_reg_offset (gdbarch, this_cache, reg, sp + offset);
}
else if (high_word == 0x27be) /* addiu $30,$sp,size */
{
/* Old gcc frame, r30 is virtual frame pointer. */
if ((long) low_word != frame_offset)
frame_addr = sp + low_word;
if (offset != frame_offset)
frame_addr = sp + offset;
else if (this_frame && frame_reg == MIPS_SP_REGNUM)
{
unsigned alloca_adjust;
@ -3491,7 +3492,7 @@ restart:
(this_frame, gdbarch_num_regs (gdbarch) + 30);
frame_offset = 0;
alloca_adjust = (unsigned) (frame_addr - (sp + low_word));
alloca_adjust = (unsigned) (frame_addr - (sp + offset));
if (alloca_adjust > 0)
{
/* FP > SP + frame_size. This may be because of
@ -3540,7 +3541,7 @@ restart:
else if ((high_word & 0xFFE0) == 0xafc0 /* sw reg,offset($30) */
&& !regsize_is_64_bits)
{
set_reg_offset (gdbarch, this_cache, reg, frame_addr + low_word);
set_reg_offset (gdbarch, this_cache, reg, frame_addr + offset);
}
else if ((high_word & 0xFFE0) == 0xE7A0 /* swc1 freg,n($sp) */
|| (high_word & 0xF3E0) == 0xA3C0 /* sx reg,n($s8) */