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* mips-tdep.c (MIPS16_INSTLEN): Define.
(mips_find_saved_regs): Replace hardcoded 2's with MIPS16_INSTLEN. (heuristic_proc_start): Recognize 'entry' pseudo-op as a start of function on MIPS16. (mips32_skip_prologue, mips16_skip_prologue): New helper functions for mips_skip_prologue. (mips_skip_prologue): Recognize both 16- and 32-bit prologues.
This commit is contained in:
Mark Alexander
parent
736a306cb2
commit
20fa0902e7
@ -1,3 +1,13 @@
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Fri Jan 31 08:26:39 1997 Mark Alexander <marka@cygnus.com>
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* mips-tdep.c (MIPS16_INSTLEN): Define.
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(mips_find_saved_regs): Replace hardcoded 2's with MIPS16_INSTLEN.
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(heuristic_proc_start): Recognize 'entry' pseudo-op as a start
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of function on MIPS16.
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(mips32_skip_prologue, mips16_skip_prologue): New helper functions
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for mips_skip_prologue.
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(mips_skip_prologue): Recognize both 16- and 32-bit prologues.
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Wed Jan 29 12:45:54 1997 Michael Meissner <meissner@tiktok.cygnus.com>
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* config/powerpc/ppc{,le}-sim.mt (SIM): Remove the library
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193
gdb/mips-tdep.c
193
gdb/mips-tdep.c
@ -43,6 +43,7 @@ extern struct obstack frame_cache_obstack;
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/* FIXME! this code assumes 4-byte instructions. */
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#define MIPS_INSTLEN 4 /* Length of an instruction */
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#define MIPS16_INSTLEN 2 /* Length of an instruction on MIPS16*/
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#define MIPS_NUMREGS 32 /* Number of integer or float registers */
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typedef unsigned long t_inst; /* Integer big enough to hold an instruction */
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@ -406,19 +407,21 @@ mips_find_saved_regs (fci)
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if ((addr = PROC_LOW_ADDR (proc_desc)) & 1)
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{
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instlen = 2; /* MIPS16 */
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instlen = MIPS16_INSTLEN; /* MIPS16 */
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addr &= ~1;
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}
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else
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instlen = MIPS_INSTLEN; /* MIPS32 */
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instlen = MIPS_INSTLEN; /* MIPS32 */
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/* Scan through this function's instructions preceding the current
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PC, and look for those that save registers. */
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while (addr < fci->pc)
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{
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status = read_memory_nobpt (addr, buf, instlen);
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if (status)
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memory_error (status, addr);
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inst = extract_unsigned_integer (buf, instlen);
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if (instlen == 2)
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if (instlen == MIPS16_INSTLEN)
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mips16_decode_reg_save (inst, &gen_save_found);
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else
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mips32_decode_reg_save (inst, &gen_save_found, &float_save_found);
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@ -446,10 +449,8 @@ mips_find_saved_regs (fci)
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if (! GDB_TARGET_IS_MIPS64)
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reg_position += 4;
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/* FIXME! this code looks scary...
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* Looks like it's trying to do stuff with a register,
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* but .... ???
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*/
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/* Fill in the offsets for the float registers which float_mask says
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were saved. */
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for (ireg = MIPS_NUMREGS-1; float_mask; --ireg, float_mask <<= 1)
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if (float_mask & 0x80000000)
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{
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@ -551,6 +552,7 @@ heuristic_proc_start(pc)
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{
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CORE_ADDR start_pc = pc;
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CORE_ADDR fence = start_pc - heuristic_fence_post;
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int instlen;
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if (start_pc == 0) return 0;
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@ -558,8 +560,10 @@ heuristic_proc_start(pc)
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|| fence < VM_MIN_ADDRESS)
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fence = VM_MIN_ADDRESS;
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instlen = pc & 1 ? MIPS16_INSTLEN : MIPS_INSTLEN;
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/* search back for previous return */
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for (start_pc -= MIPS_INSTLEN; ; start_pc -= MIPS_INSTLEN) /* FIXME!! */
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for (start_pc -= instlen; ; start_pc -= instlen)
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if (start_pc < fence)
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{
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/* It's not clear to me why we reach this point when
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@ -591,10 +595,21 @@ Otherwise, you told GDB there was a function where there isn't one, or\n\
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return 0;
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}
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else if (start_pc & 1)
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{
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/* On MIPS16, look for the 'entry' pseudo-op at the start
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of a function. This is only going to work if the program
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was compiled with -mentry. Otherwise, there's no reliable
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way of finding the start of a function. */
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if ((read_memory_integer (start_pc & ~1, 2) & 0xf81f)== 0xe809)
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return start_pc;
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}
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else if (ABOUT_TO_RETURN(start_pc))
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{
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start_pc += 2 * MIPS_INSTLEN; /* skip return, and its delay slot */
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break;
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}
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start_pc += 2 * MIPS_INSTLEN; /* skip return, and its delay slot */
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#if 0
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/* skip nops (usually 1) 0 - is this */
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while (start_pc < pc && read_memory_integer (start_pc, MIPS_INSTLEN) == 0)
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@ -1362,49 +1377,31 @@ mips_step_skips_delay (pc)
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return is_delayed ((unsigned long)extract_unsigned_integer (buf, MIPS_INSTLEN));
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}
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/* To skip prologues, I use this predicate. Returns either PC itself
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if the code at PC does not look like a function prologue; otherwise
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returns an address that (if we're lucky) follows the prologue. If
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LENIENT, then we must skip everything which is involved in setting
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up the frame (it's OK to skip more, just so long as we don't skip
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anything which might clobber the registers which are being saved.
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We must skip more in the case where part of the prologue is in the
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delay slot of a non-prologue instruction). */
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CORE_ADDR
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mips_skip_prologue (pc, lenient)
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CORE_ADDR pc;
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/* Skip the PC past function prologue instructions (32-bit version).
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This is a helper function for mips_skip_prologue. */
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static CORE_ADDR
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mips32_skip_prologue (pc, lenient)
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CORE_ADDR pc; /* starting PC to search from */
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int lenient;
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{
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t_inst inst;
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unsigned offset;
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CORE_ADDR end_pc;
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int seen_sp_adjust = 0;
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int load_immediate_bytes = 0;
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CORE_ADDR post_prologue_pc;
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/* See if we can determine the end of the prologue via the symbol table.
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If so, then return either PC, or the PC after the prologue, whichever
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is greater. */
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post_prologue_pc = after_prologue (pc, NULL);
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if (post_prologue_pc != 0)
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return max (pc, post_prologue_pc);
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/* Can't determine prologue from the symbol table, need to examine
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instructions. */
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/* Skip the typical prologue instructions. These are the stack adjustment
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instruction and the instructions that save registers on the stack
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or in the gcc frame. */
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for (offset = 0; offset < 100; offset += MIPS_INSTLEN)
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for (end_pc = pc + 100; pc < end_pc; pc += MIPS_INSTLEN)
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{
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char buf[MIPS_INSTLEN];
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int status;
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status = read_memory_nobpt (pc + offset, buf, MIPS_INSTLEN);
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status = read_memory_nobpt (pc, buf, MIPS_INSTLEN);
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if (status)
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memory_error (status, pc + offset);
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memory_error (status, pc);
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inst = (unsigned long)extract_unsigned_integer (buf, MIPS_INSTLEN);
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#if 0
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@ -1430,8 +1427,9 @@ mips_skip_prologue (pc, lenient)
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continue; /* reg != $zero */
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/* move $s8,$sp. With different versions of gas this will be either
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`addu $s8,$sp,$zero' or `or $s8,$sp,$zero'. Accept either. */
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else if (inst == 0x03A0F021 || inst == 0x03a0f025)
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`addu $s8,$sp,$zero' or `or $s8,$sp,$zero' or `daddu s8,sp,$0'.
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Accept any one of these. */
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else if (inst == 0x03A0F021 || inst == 0x03a0f025 || inst == 0x03a0f02d)
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continue;
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else if ((inst & 0xFF9F07FF) == 0x00800021) /* move reg,$a0-$a3 */
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@ -1475,12 +1473,123 @@ mips_skip_prologue (pc, lenient)
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skipped some load immediate instructions. Undo the skipping
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if the load immediate was not followed by a stack adjustment. */
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if (load_immediate_bytes && !seen_sp_adjust)
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offset -= load_immediate_bytes;
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return pc + offset;
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pc -= load_immediate_bytes;
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return pc;
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}
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/* Skip the PC past function prologue instructions (16-bit version).
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This is a helper function for mips_skip_prologue. */
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static CORE_ADDR
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mips16_skip_prologue (pc, lenient)
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CORE_ADDR pc; /* starting PC to search from */
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int lenient;
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{
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CORE_ADDR end_pc;
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/* Table of instructions likely to be found in a function prologue. */
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static struct
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{
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unsigned short inst;
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unsigned short mask;
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} table[] =
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{
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{ 0x6300, 0xff00 }, /* addiu $sp,offset */
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{ 0xfb00, 0xff00 }, /* daddiu $sp,offset */
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{ 0xd000, 0xf800 }, /* sw reg,n($sp) */
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{ 0xf900, 0xff00 }, /* sd reg,n($sp) */
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{ 0x6200, 0xff00 }, /* sw $ra,n($sp) */
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{ 0xfa00, 0xff00 }, /* sd $ra,n($sp) */
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{ 0x673d, 0xffff }, /* move $s1,sp */
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{ 0xd980, 0xff80 }, /* sw $a0-$a3,n($s1) */
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{ 0x6704, 0xff1c }, /* move reg,$a0-$a3 */
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{ 0xe809, 0xf81f }, /* entry pseudo-op */
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{ 0, 0 } /* end of table marker */
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};
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/* Skip the typical prologue instructions. These are the stack adjustment
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instruction and the instructions that save registers on the stack
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or in the gcc frame. */
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for (end_pc = pc + 100; pc < end_pc; pc += MIPS16_INSTLEN)
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{
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char buf[MIPS16_INSTLEN];
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int status;
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unsigned short inst;
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int extend_bytes;
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int prev_extend_bytes;
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int i;
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status = read_memory_nobpt (pc & ~1, buf, MIPS16_INSTLEN);
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if (status)
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memory_error (status, pc);
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inst = (unsigned long)extract_unsigned_integer (buf, MIPS16_INSTLEN);
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#if 0
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if (lenient && is_delayed (inst))
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continue;
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#endif
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/* Normally we ignore an extend instruction. However, if it is
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not followed by a valid prologue instruction, we must adjust
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the pc back over the extend so that it won't be considered
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part of the prologue. */
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if ((inst & 0xf800) == 0xf000) /* extend */
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{
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extend_bytes = MIPS16_INSTLEN;
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continue;
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}
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prev_extend_bytes = extend_bytes;
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extend_bytes = 0;
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/* Check for other valid prologue instructions besides extend. */
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for (i = 0; table[i].mask != 0; i++)
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if ((inst & table[i].mask) == table[i].inst) /* found, get out */
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break;
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if (table[i].mask != 0) /* it was in table? */
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continue; /* ignore it
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else /* non-prologue */
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{
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/* Return the current pc, adjusted backwards by 2 if
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the previous instruction was an extend. */
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return pc - prev_extend_bytes;
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}
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}
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}
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/* To skip prologues, I use this predicate. Returns either PC itself
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if the code at PC does not look like a function prologue; otherwise
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returns an address that (if we're lucky) follows the prologue. If
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LENIENT, then we must skip everything which is involved in setting
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up the frame (it's OK to skip more, just so long as we don't skip
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anything which might clobber the registers which are being saved.
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We must skip more in the case where part of the prologue is in the
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delay slot of a non-prologue instruction). */
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CORE_ADDR
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mips_skip_prologue (pc, lenient)
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CORE_ADDR pc;
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int lenient;
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{
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/* See if we can determine the end of the prologue via the symbol table.
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If so, then return either PC, or the PC after the prologue, whichever
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is greater. */
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CORE_ADDR post_prologue_pc = after_prologue (pc, NULL);
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if (post_prologue_pc != 0)
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return max (pc, post_prologue_pc);
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/* Can't determine prologue from the symbol table, need to examine
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instructions. */
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if (pc & 1)
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return mips16_skip_prologue (pc, lenient);
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else
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return mips32_skip_prologue (pc, lenient);
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}
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#if 0
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/* The lenient prologue stuff should be superceded by the code in
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/* The lenient prologue stuff should be superseded by the code in
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init_extra_frame_info which looks to see whether the stores mentioned
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in the proc_desc have actually taken place. */
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