* mips-tdep.c (mips16_decode_reg_save): Distinguish between

sd and sw instructions correctly.
	(heuristic_proc_start): Add support for MIPS16.
	(mips16_get_imm, mips16_heuristic_proc_desc,
	mips32_heuristic_proc_desc): New helper functions for
	heuristic_proc_desc.
	(heuristic_proc_desc): Rewrite and reorganize to support MIPS16.
	(mips_push_arguments): Don't align small arguments in EABI.
	(mips32_skip_prologue): Attempt to shrink code size a little.
This commit is contained in:
Mark Alexander 1997-02-04 02:09:33 +00:00
parent 7b43bcb28c
commit b348b9fd0e
2 changed files with 328 additions and 123 deletions

View File

@ -1,3 +1,15 @@
Mon Feb 03 17:57:58 1997 Mark Alexander <marka@cygnus.com>
* mips-tdep.c (mips16_decode_reg_save): Distinguish between
sd and sw instructions correctly.
(heuristic_proc_start): Add support for MIPS16.
(mips16_get_imm, mips16_heuristic_proc_desc,
mips32_heuristic_proc_desc): New helper functions for
heuristic_proc_desc.
(heuristic_proc_desc): Rewrite and reorganize to support MIPS16.
(mips_push_arguments): Don't align small arguments in EABI.
(mips32_skip_prologue): Attempt to shrink code size a little.
start-sanitize-m32r
Mon Feb 3 11:06:05 1997 Michael Snyder <msnyder@cleaver.cygnus.com>

View File

@ -295,10 +295,14 @@ mips16_decode_reg_save (inst, gen_mask)
t_inst inst;
unsigned long *gen_mask;
{
if ((inst & 0xf800) == 0xd000 /* sw reg,n($sp) */
|| (inst & 0xff00) == 0xf900) /* sd reg,n($sp) */
if ((inst & 0xf800) == 0xd000) /* sw reg,n($sp) */
{
int reg = mips16_to_32_reg[(inst & 0xf00) >> 8];
int reg = mips16_to_32_reg[(inst & 0x700) >> 8];
*gen_mask |= (1 << reg);
}
else if ((inst & 0xff00) == 0xf900) /* sd reg,n($sp) */
{
int reg = mips16_to_32_reg[(inst & 0xe0) >> 5];
*gen_mask |= (1 << reg);
}
else if ((inst & 0xff00) == 0x6200 /* sw $ra,n($sp) */
@ -553,6 +557,7 @@ heuristic_proc_start(pc)
CORE_ADDR start_pc = pc;
CORE_ADDR fence = start_pc - heuristic_fence_post;
int instlen;
int seen_adjsp = 0;
if (start_pc == 0) return 0;
@ -597,12 +602,23 @@ Otherwise, you told GDB there was a function where there isn't one, or\n\
}
else if (start_pc & 1)
{
/* On MIPS16, look for the 'entry' pseudo-op at the start
of a function. This is only going to work if the program
was compiled with -mentry. Otherwise, there's no reliable
way of finding the start of a function. */
if ((read_memory_integer (start_pc & ~1, 2) & 0xf81f)== 0xe809)
return start_pc;
/* On MIPS16, any one of the following is likely to be the
start of a function:
entry
addiu sp,-n
daddiu sp,-n
extend -n followed by 'addiu sp,+n' or 'daddiu sp,+n' */
unsigned short inst = read_memory_integer (start_pc & ~1, 2);
if (((inst & 0xf81f) == 0xe809 && (inst & 0x700) != 0x700) /* entry */
|| (inst & 0xff80) == 0x6380 /* addiu sp,-n */
|| (inst & 0xff80) == 0xfb80 /* daddiu sp,-n */
|| ((inst & 0xf810) == 0xf010 && seen_adjsp)) /* extend -n */
break;
else if ((inst & 0xff00) == 0x6300 /* addiu sp */
|| (inst & 0xff00) == 0xfb00) /* daddiu sp */
seen_adjsp = 1;
else
seen_adjsp = 0;
}
else if (ABOUT_TO_RETURN(start_pc))
{
@ -618,71 +634,227 @@ Otherwise, you told GDB there was a function where there isn't one, or\n\
return start_pc;
}
static mips_extra_func_info_t
heuristic_proc_desc(start_pc, limit_pc, next_frame)
/* Fetch the immediate value from the current instruction.
If the previous instruction was an EXTEND, use it to extend
the upper bits of the immediate value. This is a helper function
for mips16_heuristic_proc_desc. */
static int
mips16_get_imm (prev_inst, inst, nbits, scale, is_signed)
unsigned short prev_inst; /* previous instruction */
unsigned short inst; /* current current instruction */
int nbits; /* number of bits in imm field */
int scale; /* scale factor to be applied to imm */
int is_signed; /* is the imm field signed? */
{
int offset;
if ((prev_inst & 0xf800) == 0xf000) /* prev instruction was EXTEND? */
{
offset = ((prev_inst & 0x1f) << 11) | (prev_inst & 0x7e00);
if (offset & 0x8000) /* check for negative extend */
offset = 0 - (0x10000 - (offset & 0xffff));
return offset | (inst & 0x1f);
}
else
{
int max_imm = 1 << nbits;
int mask = max_imm - 1;
int sign_bit = max_imm >> 1;
offset = inst & mask;
if (is_signed && (offset & sign_bit))
offset = 0 - (max_imm - offset);
return offset * scale;
}
}
/* Fill in values in temp_proc_desc based on the MIPS16 instruction
stream from start_pc to limit_pc. */
static void
mips16_heuristic_proc_desc(start_pc, limit_pc, next_frame, sp)
CORE_ADDR start_pc, limit_pc;
struct frame_info *next_frame;
CORE_ADDR sp;
{
CORE_ADDR sp = read_next_frame_reg (next_frame, SP_REGNUM);
CORE_ADDR cur_pc;
unsigned long frame_size;
unsigned long r30_frame_size = 0;
int has_frame_reg = 0;
CORE_ADDR reg30 = 0; /* Value of $r30. Used by gcc for frame-pointer */
unsigned long reg_mask = 0;
CORE_ADDR frame_addr = 0; /* Value of $r17, used as frame pointer */
unsigned short prev_inst = 0; /* saved copy of previous instruction */
unsigned inst = 0; /* current instruction */
if (start_pc == 0) return NULL;
memset (&temp_proc_desc, '\0', sizeof(temp_proc_desc));
memset (&temp_saved_regs, '\0', sizeof(struct frame_saved_regs));
PROC_LOW_ADDR (&temp_proc_desc) = start_pc;
PROC_FRAME_OFFSET(&temp_proc_desc) = 0;
if (start_pc + 200 < limit_pc)
limit_pc = start_pc + 200;
restart:
frame_size = 0;
for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += MIPS_INSTLEN) {
char buf[MIPS_INSTLEN];
unsigned long word;
int status;
for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += MIPS16_INSTLEN)
{
char buf[MIPS16_INSTLEN];
int status, reg, offset;
status = (unsigned long) read_memory_nobpt (cur_pc, buf, MIPS_INSTLEN); /* FIXME!! */
/* Save the previous instruction. If it's an EXTEND, we'll extract
the immediate offset extension from it in mips16_get_imm. */
prev_inst = inst;
/* Fetch the instruction. */
status = read_memory_nobpt (cur_pc & ~1, buf, MIPS16_INSTLEN);
if (status) memory_error (status, cur_pc);
word = (unsigned long) extract_unsigned_integer (buf, MIPS_INSTLEN); /* FIXME!! */
inst = (unsigned short) extract_unsigned_integer (buf, MIPS16_INSTLEN);
if ((word & 0xFFFF0000) == 0x27bd0000 /* addiu $sp,$sp,-i */
|| (word & 0xFFFF0000) == 0x23bd0000 /* addi $sp,$sp,-i */
|| (word & 0xFFFF0000) == 0x67bd0000) { /* daddiu $sp,$sp,-i */
if (word & 0x8000)
frame_size += (-word) & 0xffff;
if ((inst & 0xff00) == 0x6300 /* addiu sp */
|| (inst & 0xff00) == 0xfb00) /* daddiu sp */
{
offset = mips16_get_imm (prev_inst, inst, 8, 8, 1);
if (offset < 0) /* negative stack adjustment? */
PROC_FRAME_OFFSET(&temp_proc_desc) -= offset;
else
/* Exit loop if a positive stack adjustment is found, which
usually means that the stack cleanup code in the function
epilogue is reached. */
break;
}
else if ((word & 0xFFE00000) == 0xafa00000) { /* sw reg,offset($sp) */
int reg = (word & 0x001F0000) >> 16;
reg_mask |= 1 << reg;
temp_saved_regs.regs[reg] = sp + (word & 0xffff);
else if ((inst & 0xf800) == 0xd000) /* sw reg,n($sp) */
{
offset = mips16_get_imm (prev_inst, inst, 8, 4, 0);
reg = mips16_to_32_reg[(inst & 0x700) >> 8];
PROC_REG_MASK(&temp_proc_desc) |= (1 << reg);
temp_saved_regs.regs[reg] = sp + offset;
}
else if ((word & 0xFFE00000) == 0xffa00000) { /* sd reg,offset($sp) */
else if ((inst & 0xff00) == 0xf900) /* sd reg,n($sp) */
{
offset = mips16_get_imm (prev_inst, inst, 5, 8, 0);
reg = mips16_to_32_reg[(inst & 0xe0) >> 5];
PROC_REG_MASK(&temp_proc_desc) |= (1 << reg);
temp_saved_regs.regs[reg] = sp + offset;
}
else if ((inst & 0xff00) == 0x6200) /* sw $ra,n($sp) */
{
offset = mips16_get_imm (prev_inst, inst, 8, 4, 0);
PROC_REG_MASK(&temp_proc_desc) |= (1 << 31);
temp_saved_regs.regs[31] = sp + offset;
}
else if ((inst & 0xff00) == 0xfa00) /* sd $ra,n($sp) */
{
offset = mips16_get_imm (prev_inst, inst, 8, 8, 0);
PROC_REG_MASK(&temp_proc_desc) |= (1 << 31);
temp_saved_regs.regs[31] = sp + offset;
}
else if (inst == 0x673d) /* move $s1, $sp */
{
frame_addr = read_next_frame_reg(next_frame, 30);
PROC_FRAME_REG (&temp_proc_desc) = 17;
}
else if ((inst & 0xFF00) == 0xd900) /* sw reg,offset($s1) */
{
offset = mips16_get_imm (prev_inst, inst, 5, 4, 0);
reg = mips16_to_32_reg[(inst & 0xe0) >> 5];
PROC_REG_MASK(&temp_proc_desc) |= 1 << reg;
temp_saved_regs.regs[reg] = frame_addr + offset;
}
else if ((inst & 0xFF00) == 0x7900) /* sd reg,offset($s1) */
{
offset = mips16_get_imm (prev_inst, inst, 5, 8, 0);
reg = mips16_to_32_reg[(inst & 0xe0) >> 5];
PROC_REG_MASK(&temp_proc_desc) |= 1 << reg;
temp_saved_regs.regs[reg] = frame_addr + offset;
}
else if ((inst & 0xf81f) == 0xe809 && (inst & 0x700) != 0x700) /* entry */
{
int areg_count = (inst >> 8) & 7;
int sreg_count = (inst >> 6) & 3;
/* The entry instruction always subtracts 32 from the SP. */
PROC_FRAME_OFFSET(&temp_proc_desc) += 32;
/* Check if a0-a3 were saved in the caller's argument save area. */
for (reg = 4, offset = 32; reg < areg_count+4; reg++, offset += 4)
{
PROC_REG_MASK(&temp_proc_desc) |= 1 << reg;
temp_saved_regs.regs[reg] = sp + offset;
}
/* Check if the ra register was pushed on the stack. */
offset = 28;
if (inst & 0x20)
{
PROC_REG_MASK(&temp_proc_desc) |= 1 << 31;
temp_saved_regs.regs[31] = sp + offset;
offset -= 4;
}
/* Check if the s0 and s1 registers were pushed on the stack. */
for (reg = 16; reg < sreg_count+16; reg++, offset -= 4)
{
PROC_REG_MASK(&temp_proc_desc) |= 1 << reg;
temp_saved_regs.regs[reg] = sp + offset;
}
}
}
}
static void
mips32_heuristic_proc_desc(start_pc, limit_pc, next_frame, sp)
CORE_ADDR start_pc, limit_pc;
struct frame_info *next_frame;
CORE_ADDR sp;
{
CORE_ADDR cur_pc;
CORE_ADDR frame_addr = 0; /* Value of $r30. Used by gcc for frame-pointer */
restart:
PROC_FRAME_OFFSET(&temp_proc_desc) = 0;
for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += MIPS_INSTLEN)
{
char buf[MIPS_INSTLEN];
unsigned long inst, high_word, low_word;
int status, reg;
/* Fetch the instruction. */
status = (unsigned long) read_memory_nobpt (cur_pc, buf, MIPS_INSTLEN);
if (status) memory_error (status, cur_pc);
inst = (unsigned long) extract_unsigned_integer (buf, MIPS_INSTLEN);
/* Save some code by pre-extracting some useful fields. */
high_word = (inst >> 16) & 0xffff;
low_word = inst & 0xffff;
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? */
PROC_FRAME_OFFSET(&temp_proc_desc) += 0x10000 - low_word;
else
/* Exit loop if a positive stack adjustment is found, which
usually means that the stack cleanup code in the function
epilogue is reached. */
break;
}
else if ((high_word & 0xFFE0) == 0xafa0) /* sw reg,offset($sp) */
{
PROC_REG_MASK(&temp_proc_desc) |= 1 << reg;
temp_saved_regs.regs[reg] = sp + low_word;
}
else if ((high_word & 0xFFE0) == 0xffa0) /* sd reg,offset($sp) */
{
/* Irix 6.2 N32 ABI uses sd instructions for saving $gp and $ra,
but the register size used is only 32 bits. Make the address
for the saved register point to the lower 32 bits. */
int reg = (word & 0x001F0000) >> 16;
reg_mask |= 1 << reg;
temp_saved_regs.regs[reg] = sp + (word & 0xffff) + 8 - MIPS_REGSIZE;
PROC_REG_MASK(&temp_proc_desc) |= 1 << reg;
temp_saved_regs.regs[reg] = sp + low_word + 8 - MIPS_REGSIZE;
}
else if ((word & 0xFFFF0000) == 0x27be0000) { /* addiu $30,$sp,size */
else if (high_word == 0x27be) /* addiu $30,$sp,size */
{
/* Old gcc frame, r30 is virtual frame pointer. */
if ((word & 0xffff) != frame_size)
reg30 = sp + (word & 0xffff);
else if (!has_frame_reg) {
if (low_word != PROC_FRAME_OFFSET(&temp_proc_desc))
frame_addr = sp + low_word;
else if (PROC_FRAME_REG (&temp_proc_desc) == SP_REGNUM)
{
unsigned alloca_adjust;
has_frame_reg = 1;
reg30 = read_next_frame_reg(next_frame, 30);
alloca_adjust = (unsigned)(reg30 - (sp + (word & 0xffff)));
if (alloca_adjust > 0) {
PROC_FRAME_REG (&temp_proc_desc) = 30;
frame_addr = read_next_frame_reg(next_frame, 30);
alloca_adjust = (unsigned)(frame_addr - (sp + low_word));
if (alloca_adjust > 0)
{
/* FP > SP + frame_size. This may be because
* of an alloca or somethings similar.
* Fix sp to "pre-alloca" value, and try again.
@ -692,15 +864,20 @@ heuristic_proc_desc(start_pc, limit_pc, next_frame)
}
}
}
else if ((word & 0xFFFFFFFB) == 0x03a0f021) { /* mov $30,$sp */
/* move $30,$sp. With different versions of gas this will be either
`addu $30,$sp,$zero' or `or $30,$sp,$zero' or `daddu 30,sp,$0'.
Accept any one of these. */
else if (inst == 0x03A0F021 || inst == 0x03a0f025 || inst == 0x03a0f02d)
{
/* New gcc frame, virtual frame pointer is at r30 + frame_size. */
if (!has_frame_reg) {
if (PROC_FRAME_REG (&temp_proc_desc) == SP_REGNUM)
{
unsigned alloca_adjust;
has_frame_reg = 1;
reg30 = read_next_frame_reg(next_frame, 30);
r30_frame_size = frame_size;
alloca_adjust = (unsigned)(reg30 - sp);
if (alloca_adjust > 0) {
PROC_FRAME_REG (&temp_proc_desc) = 30;
frame_addr = read_next_frame_reg(next_frame, 30);
alloca_adjust = (unsigned)(frame_addr - sp);
if (alloca_adjust > 0)
{
/* FP > SP + frame_size. This may be because
* of an alloca or somethings similar.
* Fix sp to "pre-alloca" value, and try again.
@ -710,22 +887,34 @@ heuristic_proc_desc(start_pc, limit_pc, next_frame)
}
}
}
else if ((word & 0xFFE00000) == 0xafc00000) { /* sw reg,offset($30) */
int reg = (word & 0x001F0000) >> 16;
reg_mask |= 1 << reg;
temp_saved_regs.regs[reg] = reg30 + (word & 0xffff);
else if ((high_word & 0xFFE0) == 0xafc0) /* sw reg,offset($30) */
{
PROC_REG_MASK(&temp_proc_desc) |= 1 << reg;
temp_saved_regs.regs[reg] = frame_addr + low_word;
}
}
if (has_frame_reg) {
PROC_FRAME_REG(&temp_proc_desc) = 30;
PROC_FRAME_OFFSET(&temp_proc_desc) = r30_frame_size;
}
else {
PROC_FRAME_REG(&temp_proc_desc) = SP_REGNUM;
PROC_FRAME_OFFSET(&temp_proc_desc) = frame_size;
}
PROC_REG_MASK(&temp_proc_desc) = reg_mask;
PROC_PC_REG(&temp_proc_desc) = RA_REGNUM;
}
static mips_extra_func_info_t
heuristic_proc_desc(start_pc, limit_pc, next_frame)
CORE_ADDR start_pc, limit_pc;
struct frame_info *next_frame;
{
CORE_ADDR sp = read_next_frame_reg (next_frame, SP_REGNUM);
if (start_pc == 0) return NULL;
memset (&temp_proc_desc, '\0', sizeof(temp_proc_desc));
memset (&temp_saved_regs, '\0', sizeof(struct frame_saved_regs));
PROC_LOW_ADDR (&temp_proc_desc) = start_pc;
PROC_FRAME_REG (&temp_proc_desc) = SP_REGNUM;
PROC_PC_REG (&temp_proc_desc) = RA_REGNUM;
if (start_pc + 200 < limit_pc)
limit_pc = start_pc + 200;
if (start_pc & 1)
mips16_heuristic_proc_desc (start_pc, limit_pc, next_frame, sp);
else
mips32_heuristic_proc_desc (start_pc, limit_pc, next_frame, sp);
return &temp_proc_desc;
}
@ -1054,9 +1243,11 @@ mips_push_arguments(nargs, args, sp, struct_return, struct_addr)
/* It's a simple argument being passed in a general
register.
If the argument length is smaller than the register size,
we have to adjust the argument on big endian targets. */
we have to adjust the argument on big endian targets.
But don't do this adjustment on EABI targets. */
if (TARGET_BYTE_ORDER == BIG_ENDIAN
&& partial_len < MIPS_REGSIZE)
&& partial_len < MIPS_REGSIZE
&& !MIPS_EABI)
regval <<= ((MIPS_REGSIZE - partial_len) * TARGET_CHAR_BIT);
write_register (argreg, regval);
argreg++;
@ -1398,19 +1589,21 @@ mips32_skip_prologue (pc, lenient)
{
char buf[MIPS_INSTLEN];
int status;
unsigned long high_word;
status = read_memory_nobpt (pc, buf, MIPS_INSTLEN);
if (status)
memory_error (status, pc);
inst = (unsigned long)extract_unsigned_integer (buf, MIPS_INSTLEN);
high_word = (inst >> 16) & 0xffff;
#if 0
if (lenient && is_delayed (inst))
continue;
#endif
if ((inst & 0xffff0000) == 0x27bd0000 /* addiu $sp,$sp,offset */
|| (inst & 0xffff0000) == 0x67bd0000) /* daddiu $sp,$sp,offset */
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,$t0 */
@ -1434,9 +1627,9 @@ mips32_skip_prologue (pc, lenient)
else if ((inst & 0xFF9F07FF) == 0x00800021) /* move reg,$a0-$a3 */
continue;
else if ((inst & 0xffff0000) == 0x3c1c0000) /* lui $gp,n */
else if (high_word == 0x3c1c) /* lui $gp,n */
continue;
else if ((inst & 0xffff0000) == 0x279c0000) /* addiu $gp,$gp,n */
else if (high_word == 0x279c) /* addiu $gp,$gp,n */
continue;
else if (inst == 0x0399e021 /* addu $gp,$gp,$t9 */
|| inst == 0x033ce021) /* addu $gp,$t9,$gp */
@ -1448,16 +1641,16 @@ mips32_skip_prologue (pc, lenient)
instruction was seen. */
else if (!seen_sp_adjust)
{
if ((inst & 0xffff0000) == 0x3c010000 || /* lui $at,n */
(inst & 0xffff0000) == 0x3c080000) /* lui $t0,n */
if (high_word == 0x3c01 || /* lui $at,n */
high_word == 0x3c08) /* lui $t0,n */
{
load_immediate_bytes += MIPS_INSTLEN; /* FIXME!! */
continue;
}
else if ((inst & 0xffff0000) == 0x34210000 || /* ori $at,$at,n */
(inst & 0xffff0000) == 0x35080000 || /* ori $t0,$t0,n */
(inst & 0xffff0000) == 0x34010000 || /* ori $at,$zero,n */
(inst & 0xffff0000) == 0x34080000) /* ori $t0,$zero,n */
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;