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author | Mark Alexander <marka@cygnus> | 1997-09-30 06:20:59 +0000 |
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committer | Mark Alexander <marka@cygnus> | 1997-09-30 06:20:59 +0000 |
commit | 639c86123023437b903cbb65a4fb51154956dba6 (patch) | |
tree | 22cabc787ca39376d1f01920ffa3169ae1c3374c /gdb/mips-tdep.c | |
parent | 467ad5d4b79e0b0a7b2b8b9acab198fd61f7d82c (diff) | |
download | gdb-639c86123023437b903cbb65a4fb51154956dba6.zip gdb-639c86123023437b903cbb65a4fb51154956dba6.tar.gz gdb-639c86123023437b903cbb65a4fb51154956dba6.tar.bz2 |
* mips-tdep.c (set_reg_offset): New function.
(mips16_heuristic_proc_desc): Calculate offsets of registers
saved by entry pseudo-op after rest of prologue has been read.
Use set_reg_offset to ignore all but the first save of a given
register.
(mips32_heuristic_proc_desc): Initialize frame adjustment value.
* remote-sim.c (gdbsim_store_register): Don't update registers
that have a null or empty name.
* findvar.c (read_register_bytes): Don't fetch registers
that have a null or empty name.
Diffstat (limited to 'gdb/mips-tdep.c')
-rw-r--r-- | gdb/mips-tdep.c | 116 |
1 files changed, 73 insertions, 43 deletions
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c index 9be5c20..57f3bd7 100644 --- a/gdb/mips-tdep.c +++ b/gdb/mips-tdep.c @@ -621,6 +621,21 @@ mips_frame_saved_pc(frame) static struct mips_extra_func_info temp_proc_desc; static struct frame_saved_regs temp_saved_regs; +/* Set a register's saved stack address in temp_saved_regs. If an address + has already been set for this register, do nothing; this way we will + only recognize the first save of a given register in a function prologue. + This is a helper function for mips{16,32}_heuristic_proc_desc. */ + +static void +set_reg_offset (regno, offset) + int regno; + CORE_ADDR offset; +{ + if (temp_saved_regs.regs[regno] == 0) + temp_saved_regs.regs[regno] = offset; +} + + /* This fencepost looks highly suspicious to me. Removing it also seems suspicious as it could affect remote debugging across serial lines. */ @@ -763,14 +778,14 @@ mips16_heuristic_proc_desc(start_pc, limit_pc, next_frame, sp) CORE_ADDR frame_addr = 0; /* Value of $r17, used as frame pointer */ unsigned short prev_inst = 0; /* saved copy of previous instruction */ unsigned inst = 0; /* current instruction */ + unsigned entry_inst = 0; /* the entry instruction */ + int reg, offset; PROC_FRAME_OFFSET(&temp_proc_desc) = 0; /* size of stack frame */ PROC_FRAME_ADJUST(&temp_proc_desc) = 0; /* offset of FP from SP */ for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += MIPS16_INSTLEN) { - int reg, offset; - /* Save the previous instruction. If it's an EXTEND, we'll extract the immediate offset extension from it in mips16_get_imm. */ prev_inst = inst; @@ -794,30 +809,30 @@ mips16_heuristic_proc_desc(start_pc, limit_pc, next_frame, sp) offset = mips16_get_imm (prev_inst, inst, 8, 4, 0); reg = mips16_to_32_reg[(inst & 0x700) >> 8]; PROC_REG_MASK(&temp_proc_desc) |= (1 << reg); - temp_saved_regs.regs[reg] = sp + offset; + set_reg_offset (reg, sp + offset); } else if ((inst & 0xff00) == 0xf900) /* sd reg,n($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; + set_reg_offset (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 << RA_REGNUM); - temp_saved_regs.regs[RA_REGNUM] = sp + offset; + set_reg_offset (RA_REGNUM, 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 << RA_REGNUM); - temp_saved_regs.regs[RA_REGNUM] = sp + offset; + set_reg_offset (RA_REGNUM, sp + offset); } else if (inst == 0x673d) /* move $s1, $sp */ { - frame_addr = read_next_frame_reg(next_frame, 30); + frame_addr = sp; PROC_FRAME_REG (&temp_proc_desc) = 17; } else if ((inst & 0xff00) == 0x0100) /* addiu $s1,sp,n */ @@ -832,51 +847,64 @@ mips16_heuristic_proc_desc(start_pc, limit_pc, next_frame, sp) offset = mips16_get_imm (prev_inst, inst, 5, 4, 0); reg = mips16_to_32_reg[(inst & 0xe0) >> 5]; PROC_REG_MASK(&temp_proc_desc) |= 1 << reg; - temp_saved_regs.regs[reg] = frame_addr + offset; + set_reg_offset (reg, frame_addr + offset); } else if ((inst & 0xFF00) == 0x7900) /* sd reg,offset($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; + set_reg_offset (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; + entry_inst = inst; /* save for later processing */ + else if ((inst & 0xf800) == 0x1800) /* jal(x) */ + cur_pc += MIPS16_INSTLEN; /* 32-bit instruction */ + } - /* The entry instruction always subtracts 32 from the SP. */ - PROC_FRAME_OFFSET(&temp_proc_desc) += 32; + /* The entry instruction is typically the first instruction in a function, + and it stores registers at offsets relative to the value of the old SP + (before the prologue). But the value of the sp parameter to this + function is the new SP (after the prologue has been executed). So we + can't calculate those offsets until we've seen the entire prologue, + and can calculate what the old SP must have been. */ + if (entry_inst != 0) + { + int areg_count = (entry_inst >> 8) & 7; + int sreg_count = (entry_inst >> 6) & 3; - /* Check if a0-a3 were saved in the caller's argument save area. */ - for (reg = 4, offset = 32; reg < areg_count+4; reg++) - { - PROC_REG_MASK(&temp_proc_desc) |= 1 << reg; - temp_saved_regs.regs[reg] = sp + offset; - offset -= MIPS_REGSIZE; - } + /* The entry instruction always subtracts 32 from the SP. */ + PROC_FRAME_OFFSET(&temp_proc_desc) += 32; - /* Check if the ra register was pushed on the stack. */ - offset = 28; - if (inst & 0x20) - { - PROC_REG_MASK(&temp_proc_desc) |= 1 << RA_REGNUM; - temp_saved_regs.regs[RA_REGNUM] = sp + offset; - offset -= MIPS_REGSIZE; - } + /* Now we can calculate what the SP must have been at the + start of the function prologue. */ + sp += PROC_FRAME_OFFSET(&temp_proc_desc); - /* Check if the s0 and s1 registers were pushed on the stack. */ - for (reg = 16; reg < sreg_count+16; reg++) - { - PROC_REG_MASK(&temp_proc_desc) |= 1 << reg; - temp_saved_regs.regs[reg] = sp + offset; - offset -= MIPS_REGSIZE; - } - } - else if ((inst & 0xf800) == 0x1800) /* jal(x) */ - cur_pc += MIPS16_INSTLEN; /* 32-bit instruction */ - } + /* Check if a0-a3 were saved in the caller's argument save area. */ + for (reg = 4, offset = 0; reg < areg_count+4; reg++) + { + PROC_REG_MASK(&temp_proc_desc) |= 1 << reg; + set_reg_offset (reg, sp + offset); + offset += MIPS_REGSIZE; + } + + /* Check if the ra register was pushed on the stack. */ + offset = -4; + if (entry_inst & 0x20) + { + PROC_REG_MASK(&temp_proc_desc) |= 1 << RA_REGNUM; + set_reg_offset (RA_REGNUM, sp + offset); + offset -= MIPS_REGSIZE; + } + + /* Check if the s0 and s1 registers were pushed on the stack. */ + for (reg = 16; reg < sreg_count+16; reg++) + { + PROC_REG_MASK(&temp_proc_desc) |= 1 << reg; + set_reg_offset (reg, sp + offset); + offset -= MIPS_REGSIZE; + } + } } static void @@ -889,6 +917,7 @@ mips32_heuristic_proc_desc(start_pc, limit_pc, next_frame, sp) CORE_ADDR frame_addr = 0; /* Value of $r30. Used by gcc for frame-pointer */ restart: PROC_FRAME_OFFSET(&temp_proc_desc) = 0; + PROC_FRAME_ADJUST (&temp_proc_desc) = 0; /* offset of FP from SP */ for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += MIPS_INSTLEN) { unsigned long inst, high_word, low_word; @@ -917,7 +946,7 @@ restart: else if ((high_word & 0xFFE0) == 0xafa0) /* sw reg,offset($sp) */ { PROC_REG_MASK(&temp_proc_desc) |= 1 << reg; - temp_saved_regs.regs[reg] = sp + low_word; + set_reg_offset (reg, sp + low_word); } else if ((high_word & 0xFFE0) == 0xffa0) /* sd reg,offset($sp) */ { @@ -925,7 +954,7 @@ restart: 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; + set_reg_offset (reg, sp + low_word + 8 - MIPS_REGSIZE); } else if (high_word == 0x27be) /* addiu $30,$sp,size */ { @@ -975,7 +1004,7 @@ restart: 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; + set_reg_offset (reg, frame_addr + low_word); } } } @@ -1513,6 +1542,7 @@ mips_push_dummy_frame() /* Save special registers (PC, MMHI, MMLO, FPC_CSR) */ PROC_FRAME_REG(proc_desc) = PUSH_FP_REGNUM; PROC_FRAME_OFFSET(proc_desc) = 0; + PROC_FRAME_ADJUST(proc_desc) = 0; mips_push_register (&sp, PC_REGNUM); mips_push_register (&sp, HI_REGNUM); mips_push_register (&sp, LO_REGNUM); |