From b348b9fd0eaa0a02916e4b1e32fc047016058d57 Mon Sep 17 00:00:00 2001 From: Mark Alexander Date: Tue, 4 Feb 1997 02:09:33 +0000 Subject: [PATCH] * 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. --- gdb/ChangeLog | 12 ++ gdb/mips-tdep.c | 421 +++++++++++++++++++++++++++++++++++------------- 2 files changed, 319 insertions(+), 114 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 77275c2cfe0..07c5f9ad6d6 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,15 @@ +Mon Feb 03 17:57:58 1997 Mark Alexander + + * 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 diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c index 7d331cc393a..75f10d1e561 100644 --- a/gdb/mips-tdep.c +++ b/gdb/mips-tdep.c @@ -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)) { @@ -618,115 +634,288 @@ 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; - - 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; - - 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; + CORE_ADDR cur_pc; + 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 */ - status = (unsigned long) read_memory_nobpt (cur_pc, buf, MIPS_INSTLEN); /* FIXME!! */ - if (status) memory_error (status, cur_pc); - word = (unsigned long) extract_unsigned_integer (buf, MIPS_INSTLEN); /* FIXME!! */ + PROC_FRAME_OFFSET(&temp_proc_desc) = 0; - 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; - 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; + for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += MIPS16_INSTLEN) + { + char buf[MIPS16_INSTLEN]; + int status, reg, offset; + + /* 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); + inst = (unsigned short) extract_unsigned_integer (buf, MIPS16_INSTLEN); + + 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 ((inst & 0xf800) == 0xd000) /* sw reg,n($sp) */ + { + offset = mips16_get_imm (prev_inst, inst, 8, 4, 0); + reg = mips16_to_32_reg[(inst & 0x700) >> 8]; + PROC_REG_MASK(&temp_proc_desc) |= (1 << reg); + temp_saved_regs.regs[reg] = sp + offset; + } + else if ((inst & 0xff00) == 0xf900) /* sd reg,n($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 ((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 & 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 ((word & 0xFFE00000) == 0xffa00000) { /* 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; + 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 ((word & 0xFFFF0000) == 0x27be0000) { /* 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) { - 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) { - /* FP > SP + frame_size. This may be because - * of an alloca or somethings similar. - * Fix sp to "pre-alloca" value, and try again. - */ - sp += alloca_adjust; - goto restart; + 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. */ + PROC_REG_MASK(&temp_proc_desc) |= 1 << reg; + temp_saved_regs.regs[reg] = sp + low_word + 8 - MIPS_REGSIZE; + } + else if (high_word == 0x27be) /* addiu $30,$sp,size */ + { + /* Old gcc frame, r30 is virtual frame pointer. */ + 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; + 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. + */ + sp += alloca_adjust; + goto restart; } } } - else if ((word & 0xFFFFFFFB) == 0x03a0f021) { /* mov $30,$sp */ - /* New gcc frame, virtual frame pointer is at r30 + frame_size. */ - if (!has_frame_reg) { - 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) { - /* FP > SP + frame_size. This may be because - * of an alloca or somethings similar. - * Fix sp to "pre-alloca" value, and try again. - */ - sp += alloca_adjust; - goto restart; + /* 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 (PROC_FRAME_REG (&temp_proc_desc) == SP_REGNUM) + { + unsigned alloca_adjust; + 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. + */ + sp += alloca_adjust; + goto restart; } } } - 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; - return &temp_proc_desc; +} + +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; } static mips_extra_func_info_t @@ -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; -- 2.30.2