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Fix PR breakpoints/2080.

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* i386-tdep.c (struct i386_frame_cache): Add stack_align member.
(i386_analyze_stack_align): New function.
(i386_analyze_prologue): Use i386_analyze_stack_align.
(i386_frame_cache): Deal with stack realignment.
This commit is contained in:
Mark Kettenis
2006-02-14 15:41:59 +00:00
parent b3ded179bb
commit 92dd43fa3b
2 changed files with 61 additions and 3 deletions
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56
gdb/i386-tdep.c
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@@ -308,6 +308,7 @@ struct i386_frame_cache
/* Saved registers. */
CORE_ADDR saved_regs[I386_NUM_SAVED_REGS];
CORE_ADDR saved_sp;
int stack_align;
int pc_in_eax;
/* Stack space reserved for local variables. */
@@ -334,6 +335,7 @@ i386_alloc_frame_cache (void)
for (i = 0; i < I386_NUM_SAVED_REGS; i++)
cache->saved_regs[i] = -1;
cache->saved_sp = 0;
cache->stack_align = 0;
cache->pc_in_eax = 0;
/* Frameless until proven otherwise. */
@@ -485,6 +487,33 @@ i386_skip_probe (CORE_ADDR pc)
return pc;
}
/* GCC 4.1 and later, can put code in the prologue to realign the
stack pointer. Check whether PC points to such code, and update
CACHE accordingly. Return the first instruction after the code
sequence or CURRENT_PC, whichever is smaller. If we don't
recognize the code, return PC. */
static CORE_ADDR
i386_analyze_stack_align (CORE_ADDR pc, CORE_ADDR current_pc,
struct i386_frame_cache *cache)
{
static const gdb_byte insns[10] = {
0x8d, 0x4c, 0x24, 0x04, /* leal 4(%esp), %ecx */
0x83, 0xe4, 0xf0, /* andl $-16, %esp */
0xff, 0x71, 0xfc /* pushl -4(%ecx) */
};
gdb_byte buf[10];
if (target_read_memory (pc, buf, sizeof buf)
|| memcmp (buf, insns, sizeof buf) != 0)
return pc;
if (current_pc > pc + 4)
cache->stack_align = 1;
return min (pc + 10, current_pc);
}
/* Maximum instruction length we need to handle. */
#define I386_MAX_INSN_LEN 6
@@ -777,6 +806,7 @@ i386_analyze_prologue (CORE_ADDR pc, CORE_ADDR current_pc,
pc = i386_follow_jump (pc);
pc = i386_analyze_struct_return (pc, current_pc, cache);
pc = i386_skip_probe (pc);
pc = i386_analyze_stack_align (pc, current_pc, cache);
pc = i386_analyze_frame_setup (pc, current_pc, cache);
return i386_analyze_register_saves (pc, current_pc, cache);
}
@@ -907,6 +937,13 @@ i386_frame_cache (struct frame_info *next_frame, void **this_cache)
if (cache->pc != 0)
i386_analyze_prologue (cache->pc, frame_pc_unwind (next_frame), cache);
if (cache->stack_align)
{
/* Saved stack pointer has been saved in %ecx. */
frame_unwind_register (next_frame, I386_ECX_REGNUM, buf);
cache->saved_sp = extract_unsigned_integer(buf, 4);
}
if (cache->locals < 0)
{
/* We didn't find a valid frame, which means that CACHE->base
@@ -917,13 +954,26 @@ i386_frame_cache (struct frame_info *next_frame, void **this_cache)
frame by looking at the stack pointer. For truly "frameless"
functions this might work too. */
frame_unwind_register (next_frame, I386_ESP_REGNUM, buf);
cache->base = extract_unsigned_integer (buf, 4) + cache->sp_offset;
if (cache->stack_align)
{
/* We're halfway aligning the stack. */
cache->base = ((cache->saved_sp - 4) & 0xfffffff0) - 4;
cache->saved_regs[I386_EIP_REGNUM] = cache->saved_sp - 4;
/* This will be added back below. */
cache->saved_regs[I386_EIP_REGNUM] -= cache->base;
}
else
{
frame_unwind_register (next_frame, I386_ESP_REGNUM, buf);
cache->base = extract_unsigned_integer (buf, 4) + cache->sp_offset;
}
}
/* Now that we have the base address for the stack frame we can
calculate the value of %esp in the calling frame. */
cache->saved_sp = cache->base + 8;
if (cache->saved_sp == 0)
cache->saved_sp = cache->base + 8;
/* Adjust all the saved registers such that they contain addresses
instead of offsets. */