}
/* Analyze the function prologue from START_PC to LIMIT_PC. Builds
- the associated FRAME_CACHE if not null. */
+ the associated FRAME_CACHE if not null.
+ Return the address of the first instruction past the prologue. */
-static void
+static CORE_ADDR
mips32_scan_prologue (CORE_ADDR start_pc, CORE_ADDR limit_pc, CORE_ADDR sp,
struct frame_info *next_frame,
struct mips_frame_cache *this_cache)
long frame_offset;
int frame_reg = MIPS_SP_REGNUM;
+ CORE_ADDR end_prologue_addr = 0;
+ int seen_sp_adjust = 0;
+ int load_immediate_bytes = 0;
+
restart:
frame_offset = 0;
usually means that the stack cleanup code in the function
epilogue is reached. */
break;
+ seen_sp_adjust = 1;
}
else if ((high_word & 0xFFE0) == 0xafa0) /* sw reg,offset($sp) */
{
}
else if ((high_word & 0xFFE0) == 0xffa0) /* sd reg,offset($sp) */
{
- /* Irix 6.2 N32 ABI uses sd instructions for saving $gp and
- $ra. */
+ /* Irix 6.2 N32 ABI uses sd instructions for saving $gp and $ra. */
set_reg_offset (this_cache, reg, sp + low_word);
}
else if (high_word == 0x27be) /* addiu $30,$sp,size */
{
set_reg_offset (this_cache, reg, frame_addr + low_word);
}
+ else if ((high_word & 0xFFE0) == 0xE7A0 /* swc1 freg,n($sp) */
+ || (high_word & 0xF3E0) == 0xA3C0 /* sx reg,n($s8) */
+ || (inst & 0xFF9F07FF) == 0x00800021 /* move reg,$a0-$a3 */
+ || high_word == 0x3c1c /* lui $gp,n */
+ || high_word == 0x279c /* addiu $gp,$gp,n */
+ || inst == 0x0399e021 /* addu $gp,$gp,$t9 */
+ || inst == 0x033ce021 /* addu $gp,$t9,$gp */
+ )
+ {
+ /* These instructions are part of the prologue, but we don't
+ need to do anything special to handle them. */
+ }
+ /* The instructions below load $at or $t0 with an immediate
+ value in preparation for a stack adjustment via
+ subu $sp,$sp,[$at,$t0]. These instructions could also
+ initialize a local variable, so we accept them only before
+ a stack adjustment instruction was seen. */
+ else if (!seen_sp_adjust
+ && (high_word == 0x3c01 /* lui $at,n */
+ || high_word == 0x3c08 /* lui $t0,n */
+ || high_word == 0x3421 /* ori $at,$at,n */
+ || high_word == 0x3508 /* ori $t0,$t0,n */
+ || high_word == 0x3401 /* ori $at,$zero,n */
+ || high_word == 0x3408 /* ori $t0,$zero,n */
+ ))
+ {
+ load_immediate_bytes += MIPS_INSTLEN; /* FIXME!! */
+ }
+ else
+ {
+ /* This instruction is not an instruction typically found
+ in a prologue, so we must have reached the end of the
+ prologue. */
+ /* FIXME: brobecker/2004-10-10: Can't we just break out of this
+ loop now? Why would we need to continue scanning the function
+ instructions? */
+ if (end_prologue_addr == 0)
+ end_prologue_addr = cur_pc;
+ }
}
if (this_cache != NULL)
this_cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->pc]
= this_cache->saved_regs[NUM_REGS + RA_REGNUM];
}
+
+ /* If we didn't reach the end of the prologue when scanning the function
+ instructions, then set end_prologue_addr to the address of the
+ instruction immediately after the last one we scanned. */
+ /* brobecker/2004-10-10: I don't think this would ever happen, but
+ we may as well be careful and do our best if we have a null
+ end_prologue_addr. */
+ if (end_prologue_addr == 0)
+ end_prologue_addr = cur_pc;
+
+ /* In a frameless function, we might have incorrectly
+ skipped some load immediate instructions. Undo the skipping
+ if the load immediate was not followed by a stack adjustment. */
+ if (load_immediate_bytes && !seen_sp_adjust)
+ end_prologue_addr -= load_immediate_bytes;
+
+ return end_prologue_addr;
}
static mips_extra_func_info_t
extract_unsigned_integer (buf, MIPS_INSTLEN));
}
-/* Skip the PC past function prologue instructions (32-bit version).
- This is a helper function for mips_skip_prologue. */
-
-static CORE_ADDR
-mips32_skip_prologue (CORE_ADDR pc)
-{
- t_inst inst;
- CORE_ADDR end_pc;
- int seen_sp_adjust = 0;
- int load_immediate_bytes = 0;
-
- /* Find an upper bound on the prologue. */
- end_pc = skip_prologue_using_sal (pc);
- if (end_pc == 0)
- end_pc = pc + 100; /* Magic. */
-
- /* Skip the typical prologue instructions. These are the stack adjustment
- instruction and the instructions that save registers on the stack
- or in the gcc frame. */
- for (; pc < end_pc; pc += MIPS_INSTLEN)
- {
- unsigned long high_word;
-
- inst = mips_fetch_instruction (pc);
- high_word = (inst >> 16) & 0xffff;
-
- if (high_word == 0x27bd /* addiu $sp,$sp,offset */
- || high_word == 0x67bd) /* daddiu $sp,$sp,offset */
- seen_sp_adjust = 1;
- else if (inst == 0x03a1e823 || /* subu $sp,$sp,$at */
- inst == 0x03a8e823) /* subu $sp,$sp,$t0 */
- seen_sp_adjust = 1;
- else if (((inst & 0xFFE00000) == 0xAFA00000 /* sw reg,n($sp) */
- || (inst & 0xFFE00000) == 0xFFA00000) /* sd reg,n($sp) */
- && (inst & 0x001F0000)) /* reg != $zero */
- continue;
-
- else if ((inst & 0xFFE00000) == 0xE7A00000) /* swc1 freg,n($sp) */
- continue;
- else if ((inst & 0xF3E00000) == 0xA3C00000 && (inst & 0x001F0000))
- /* sx reg,n($s8) */
- continue; /* reg != $zero */
-
- /* move $s8,$sp. With different versions of gas this will be either
- `addu $s8,$sp,$zero' or `or $s8,$sp,$zero' or `daddu s8,sp,$0'.
- Accept any one of these. */
- else if (inst == 0x03A0F021 || inst == 0x03a0f025 || inst == 0x03a0f02d)
- continue;
-
- else if ((inst & 0xFF9F07FF) == 0x00800021) /* move reg,$a0-$a3 */
- continue;
- else if (high_word == 0x3c1c) /* lui $gp,n */
- continue;
- else if (high_word == 0x279c) /* addiu $gp,$gp,n */
- continue;
- else if (inst == 0x0399e021 /* addu $gp,$gp,$t9 */
- || inst == 0x033ce021) /* addu $gp,$t9,$gp */
- continue;
- /* The following instructions load $at or $t0 with an immediate
- value in preparation for a stack adjustment via
- subu $sp,$sp,[$at,$t0]. These instructions could also initialize
- a local variable, so we accept them only before a stack adjustment
- instruction was seen. */
- else if (!seen_sp_adjust)
- {
- if (high_word == 0x3c01 || /* lui $at,n */
- high_word == 0x3c08) /* lui $t0,n */
- {
- load_immediate_bytes += MIPS_INSTLEN; /* FIXME!! */
- continue;
- }
- else if (high_word == 0x3421 || /* ori $at,$at,n */
- high_word == 0x3508 || /* ori $t0,$t0,n */
- high_word == 0x3401 || /* ori $at,$zero,n */
- high_word == 0x3408) /* ori $t0,$zero,n */
- {
- load_immediate_bytes += MIPS_INSTLEN; /* FIXME!! */
- continue;
- }
- else
- break;
- }
- else
- break;
- }
-
- /* In a frameless function, we might have incorrectly
- skipped some load immediate instructions. Undo the skipping
- if the load immediate was not followed by a stack adjustment. */
- if (load_immediate_bytes && !seen_sp_adjust)
- pc -= load_immediate_bytes;
- return pc;
-}
-
/* Skip the PC past function prologue instructions (16-bit version).
This is a helper function for mips_skip_prologue. */
static CORE_ADDR
-mips16_skip_prologue (CORE_ADDR pc)
+mips16_skip_prologue (CORE_ADDR pc, CORE_ADDR end_pc)
{
- CORE_ADDR end_pc;
int extend_bytes = 0;
int prev_extend_bytes;
0, 0} /* end of table marker */
};
- /* Find an upper bound on the prologue. */
- end_pc = skip_prologue_using_sal (pc);
- if (end_pc == 0)
- end_pc = pc + 100; /* Magic. */
-
/* Skip the typical prologue instructions. These are the stack adjustment
instruction and the instructions that save registers on the stack
or in the gcc frame. */
is greater. */
CORE_ADDR post_prologue_pc = after_prologue (pc);
+ CORE_ADDR limit_pc;
if (post_prologue_pc != 0)
return max (pc, post_prologue_pc);
/* Can't determine prologue from the symbol table, need to examine
instructions. */
+ /* Find an upper limit on the function prologue using the debug
+ information. If the debug information could not be used to provide
+ that bound, then use an arbitrary large number as the upper bound. */
+ limit_pc = skip_prologue_using_sal (pc);
+ if (limit_pc == 0)
+ limit_pc = pc + 100; /* Magic. */
+
if (pc_is_mips16 (pc))
- return mips16_skip_prologue (pc);
+ return mips16_skip_prologue (pc, limit_pc);
else
- return mips32_skip_prologue (pc);
+ return mips32_scan_prologue (pc, limit_pc, 0, NULL, NULL);
}
/* Root of all "set mips "/"show mips " commands. This will eventually be
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