/* Target-dependent code for the MIPS architecture, for GDB, the GNU Debugger. Copyright 1988, 1989, 1990, 1991 Free Software Foundation, Inc. Contributed by Alessandro Forin(af@cs.cmu.edu) at CMU and by Per Bothner(bothner@cs.wisc.edu) at U.Wisconsin. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include "defs.h" #include "frame.h" #include "inferior.h" #include "symtab.h" #include "value.h" #include "gdbcmd.h" #include "language.h" #ifdef USG #include #endif #include #include #include #include #include "gdbcore.h" #ifndef MIPSMAGIC #ifdef MIPSEL #define MIPSMAGIC MIPSELMAGIC #else #define MIPSMAGIC MIPSEBMAGIC #endif #endif #define VM_MIN_ADDRESS (unsigned)0x400000 #include /* After a.out.h */ #include #include #define PROC_LOW_ADDR(proc) ((proc)->adr) /* least address */ #define PROC_HIGH_ADDR(proc) ((proc)->pad2) /* upper address bound */ #define PROC_FRAME_OFFSET(proc) ((proc)->framesize) #define PROC_FRAME_REG(proc) ((proc)->framereg) #define PROC_REG_MASK(proc) ((proc)->regmask) #define PROC_FREG_MASK(proc) ((proc)->fregmask) #define PROC_REG_OFFSET(proc) ((proc)->regoffset) #define PROC_FREG_OFFSET(proc) ((proc)->fregoffset) #define PROC_PC_REG(proc) ((proc)->pcreg) #define PROC_SYMBOL(proc) (*(struct symbol**)&(proc)->isym) #define _PROC_MAGIC_ 0x0F0F0F0F #define PROC_DESC_IS_DUMMY(proc) ((proc)->isym == _PROC_MAGIC_) #define SET_PROC_DESC_IS_DUMMY(proc) ((proc)->isym = _PROC_MAGIC_) struct linked_proc_info { struct mips_extra_func_info info; struct linked_proc_info *next; } * linked_proc_desc_table = NULL; #define READ_FRAME_REG(fi, regno) read_next_frame_reg((fi)->next, regno) int read_next_frame_reg(fi, regno) FRAME fi; int regno; { #define SIGFRAME_BASE sizeof(struct sigcontext) #define SIGFRAME_PC_OFF (-SIGFRAME_BASE+ 2*sizeof(int)) #define SIGFRAME_SP_OFF (-SIGFRAME_BASE+32*sizeof(int)) #define SIGFRAME_RA_OFF (-SIGFRAME_BASE+34*sizeof(int)) for (; fi; fi = fi->next) if (in_sigtramp(fi->pc, 0)) { /* No idea if this code works. --PB. */ int offset; if (regno == PC_REGNUM) offset = SIGFRAME_PC_OFF; else if (regno == RA_REGNUM) offset = SIGFRAME_RA_OFF; else if (regno == SP_REGNUM) offset = SIGFRAME_SP_OFF; else return 0; return read_memory_integer(fi->frame + offset, 4); } else if (regno == SP_REGNUM) return fi->frame; else if (fi->saved_regs->regs[regno]) return read_memory_integer(fi->saved_regs->regs[regno], 4); return read_register(regno); } int mips_frame_saved_pc(frame) FRAME frame; { mips_extra_func_info_t proc_desc = (mips_extra_func_info_t)frame->proc_desc; int pcreg = proc_desc ? PROC_PC_REG(proc_desc) : RA_REGNUM; if (proc_desc && PROC_DESC_IS_DUMMY(proc_desc)) return read_memory_integer(frame->frame - 4, 4); #if 0 /* If in the procedure prologue, RA_REGNUM might not have been saved yet. * Assume non-leaf functions start with: * addiu $sp,$sp,-frame_size * sw $ra,ra_offset($sp) * This if the pc is pointing at either of these instructions, * then $ra hasn't been trashed. * If the pc has advanced beyond these two instructions, * then $ra has been saved. * critical, and much more complex. Handling $ra is enough to get * a stack trace, but some register values with be wrong. */ if (frame->proc_desc && frame->pc < PROC_LOW_ADDR(proc_desc) + 8) return read_register(pcreg); #endif return read_next_frame_reg(frame, pcreg); } static struct mips_extra_func_info temp_proc_desc; static struct frame_saved_regs temp_saved_regs; CORE_ADDR heuristic_proc_start(pc) CORE_ADDR pc; { CORE_ADDR start_pc = pc; CORE_ADDR fence = start_pc - 10000; if (fence < VM_MIN_ADDRESS) fence = VM_MIN_ADDRESS; /* search back for previous return */ for (start_pc -= 4; ; start_pc -= 4) if (start_pc < fence) return 0; else if (ABOUT_TO_RETURN(start_pc)) break; start_pc += 8; /* skip return, and its delay slot */ #if 0 /* skip nops (usually 1) 0 - is this */ while (start_pc < pc && read_memory_integer (start_pc, 4) == 0) start_pc += 4; #endif return start_pc; } mips_extra_func_info_t heuristic_proc_desc(start_pc, limit_pc, next_frame) CORE_ADDR start_pc, limit_pc; FRAME next_frame; { CORE_ADDR sp = next_frame ? next_frame->frame : read_register (SP_REGNUM); CORE_ADDR cur_pc; int frame_size; int has_frame_reg = 0; int reg30; /* Value of $r30. Used by gcc for frame-pointer */ unsigned long reg_mask = 0; if (start_pc == 0) return NULL; bzero(&temp_proc_desc, sizeof(temp_proc_desc)); bzero(&temp_saved_regs, sizeof(struct frame_saved_regs)); 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 += 4) { unsigned long word; int status; status = read_memory_nobpt (cur_pc, &word, 4); if (status) memory_error (status, cur_pc); if ((word & 0xFFFF0000) == 0x27bd0000) /* addiu $sp,$sp,-i */ frame_size += (-word) & 0xFFFF; else if ((word & 0xFFFF0000) == 0x23bd0000) /* addu $sp,$sp,-i */ frame_size += (-word) & 0xFFFF; else if ((word & 0xFFE00000) == 0xafa00000) { /* sw reg,offset($sp) */ int reg = (word & 0x001F0000) >> 16; reg_mask |= 1 << reg; temp_saved_regs.regs[reg] = sp + (short)word; } else if ((word & 0xFFFF0000) == 0x27be0000) { /* addiu $30,$sp,size */ if ((unsigned short)word != frame_size) reg30 = sp + (unsigned short)word; else if (!has_frame_reg) { int alloca_adjust; has_frame_reg = 1; reg30 = read_next_frame_reg(next_frame, 30); alloca_adjust = reg30 - (sp + (unsigned short)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 & 0xFFE00000) == 0xafc00000) { /* sw reg,offset($30) */ int reg = (word & 0x001F0000) >> 16; reg_mask |= 1 << reg; temp_saved_regs.regs[reg] = reg30 + (short)word; } } if (has_frame_reg) { PROC_FRAME_REG(&temp_proc_desc) = 30; PROC_FRAME_OFFSET(&temp_proc_desc) = 0; } 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; } mips_extra_func_info_t find_proc_desc(pc, next_frame) CORE_ADDR pc; FRAME next_frame; { mips_extra_func_info_t proc_desc; extern struct block *block_for_pc(); struct block *b = block_for_pc(pc); struct symbol *sym = b ? lookup_symbol(".gdbinfo.", b, LABEL_NAMESPACE, 0, NULL) : NULL; if (sym != NULL) { /* IF this is the topmost frame AND * (this proc does not have debugging information OR * the PC is in the procedure prologue) * THEN create a "hueristic" proc_desc (by analyzing * the actual code) to replace the "official" proc_desc. */ proc_desc = (struct mips_extra_func_info *)sym->value.value; if (next_frame == NULL) { struct symtab_and_line val; struct symbol *proc_symbol = PROC_DESC_IS_DUMMY(proc_desc) ? 0 : PROC_SYMBOL(proc_desc); if (proc_symbol) { val = find_pc_line (BLOCK_START (SYMBOL_BLOCK_VALUE(proc_symbol)), 0); val.pc = val.end ? val.end : pc; } if (!proc_symbol || pc < val.pc) { mips_extra_func_info_t found_heuristic = heuristic_proc_desc(PROC_LOW_ADDR(proc_desc), pc, next_frame); if (found_heuristic) proc_desc = found_heuristic; } } } else { register struct linked_proc_info *link; for (link = linked_proc_desc_table; link; link = link->next) if (PROC_LOW_ADDR(&link->info) <= pc && PROC_HIGH_ADDR(&link->info) > pc) return &link->info; proc_desc = heuristic_proc_desc(heuristic_proc_start(pc), pc, next_frame); } return proc_desc; } mips_extra_func_info_t cached_proc_desc; FRAME_ADDR mips_frame_chain(frame) FRAME frame; { extern CORE_ADDR startup_file_start; /* From blockframe.c */ mips_extra_func_info_t proc_desc; CORE_ADDR saved_pc = FRAME_SAVED_PC(frame); if (startup_file_start) { /* has at least the __start symbol */ if (saved_pc == 0 || !outside_startup_file (saved_pc)) return 0; } else { /* This hack depends on the internals of __start. */ /* We also assume the breakpoints are *not* inserted */ if (saved_pc == 0 || read_memory_integer (saved_pc + 8, 4) & 0xFC00003F == 0xD) return 0; /* break */ } proc_desc = find_proc_desc(saved_pc, frame); if (!proc_desc) return 0; cached_proc_desc = proc_desc; return read_next_frame_reg(frame, PROC_FRAME_REG(proc_desc)) + PROC_FRAME_OFFSET(proc_desc); } void init_extra_frame_info(fci) struct frame_info *fci; { extern struct obstack frame_cache_obstack; /* Use proc_desc calculated in frame_chain */ mips_extra_func_info_t proc_desc = fci->next ? cached_proc_desc : find_proc_desc(fci->pc, fci->next); fci->saved_regs = (struct frame_saved_regs*) obstack_alloc (&frame_cache_obstack, sizeof(struct frame_saved_regs)); bzero(fci->saved_regs, sizeof(struct frame_saved_regs)); fci->proc_desc = proc_desc == &temp_proc_desc ? (char*)NULL : (char*)proc_desc; if (proc_desc) { int ireg; CORE_ADDR reg_position; unsigned long mask; /* r0 bit means kernel trap */ int kernel_trap = PROC_REG_MASK(proc_desc) & 1; /* Fixup frame-pointer - only needed for top frame */ /* This may not be quite right, if procedure has a real frame register */ if (fci->pc == PROC_LOW_ADDR(proc_desc)) fci->frame = read_register (SP_REGNUM); else fci->frame = READ_FRAME_REG(fci, PROC_FRAME_REG(proc_desc)) + PROC_FRAME_OFFSET(proc_desc); if (proc_desc == &temp_proc_desc) *fci->saved_regs = temp_saved_regs; else { /* find which general-purpose registers were saved */ reg_position = fci->frame + PROC_REG_OFFSET(proc_desc); mask = kernel_trap ? 0xFFFFFFFF : PROC_REG_MASK(proc_desc); for (ireg= 31; mask; --ireg, mask <<= 1) if (mask & 0x80000000) { fci->saved_regs->regs[ireg] = reg_position; reg_position -= 4; } /* find which floating-point registers were saved */ reg_position = fci->frame + PROC_FREG_OFFSET(proc_desc); /* The freg_offset points to where the first *double* register is saved. * So skip to the high-order word. */ reg_position += 4; mask = kernel_trap ? 0xFFFFFFFF : PROC_FREG_MASK(proc_desc); for (ireg = 31; mask; --ireg, mask <<= 1) if (mask & 0x80000000) { fci->saved_regs->regs[32+ireg] = reg_position; reg_position -= 4; } } /* hack: if argument regs are saved, guess these contain args */ if ((PROC_REG_MASK(proc_desc) & 0xF0) == 0) fci->num_args = -1; else if ((PROC_REG_MASK(proc_desc) & 0x80) == 0) fci->num_args = 4; else if ((PROC_REG_MASK(proc_desc) & 0x40) == 0) fci->num_args = 3; else if ((PROC_REG_MASK(proc_desc) & 0x20) == 0) fci->num_args = 2; else if ((PROC_REG_MASK(proc_desc) & 0x10) == 0) fci->num_args = 1; fci->saved_regs->regs[PC_REGNUM] = fci->saved_regs->regs[RA_REGNUM]; } if (fci->next == 0) supply_register(FP_REGNUM, &fci->frame); } CORE_ADDR mips_push_arguments(nargs, args, sp, struct_return, struct_addr) int nargs; value *args; CORE_ADDR sp; int struct_return; CORE_ADDR struct_addr; { CORE_ADDR buf; register i; int accumulate_size = struct_return ? 4 : 0; struct mips_arg { char *contents; int len; int offset; }; struct mips_arg *mips_args = (struct mips_arg*)alloca(nargs * sizeof(struct mips_arg)); register struct mips_arg *m_arg; for (i = 0, m_arg = mips_args; i < nargs; i++, m_arg++) { extern value value_arg_coerce(); value arg = value_arg_coerce (args[i]); m_arg->len = TYPE_LENGTH (VALUE_TYPE (arg)); /* This entire mips-specific routine is because doubles must be aligned * on 8-byte boundaries. It still isn't quite right, because MIPS decided * to align 'struct {int a, b}' on 4-byte boundaries (even though this * breaks their varargs implementation...). A correct solution * requires an simulation of gcc's 'alignof' (and use of 'alignof' * in stdarg.h/varargs.h). */ if (m_arg->len > 4) accumulate_size = (accumulate_size + 7) & -8; m_arg->offset = accumulate_size; accumulate_size = (accumulate_size + m_arg->len + 3) & -4; m_arg->contents = VALUE_CONTENTS(arg); } accumulate_size = (accumulate_size + 7) & (-8); if (accumulate_size < 16) accumulate_size = 16; sp -= accumulate_size; for (i = nargs; m_arg--, --i >= 0; ) write_memory(sp + m_arg->offset, m_arg->contents, m_arg->len); if (struct_return) { buf = struct_addr; write_memory(sp, &buf, sizeof(CORE_ADDR)); } return sp; } /* MASK(i,j) == (1<info; CORE_ADDR sp = read_register (SP_REGNUM); CORE_ADDR save_address; REGISTER_TYPE buffer; link->next = linked_proc_desc_table; linked_proc_desc_table = link; #define PUSH_FP_REGNUM 16 /* must be a register preserved across calls */ #define GEN_REG_SAVE_MASK MASK(1,16)|MASK(24,28)|(1<<31) #define GEN_REG_SAVE_COUNT 22 #define FLOAT_REG_SAVE_MASK MASK(0,19) #define FLOAT_REG_SAVE_COUNT 20 #define SPECIAL_REG_SAVE_COUNT 4 /* * The registers we must save are all those not preserved across * procedure calls. Dest_Reg (see tm-mips.h) must also be saved. * In addition, we must save the PC, and PUSH_FP_REGNUM. * (Ideally, we should also save MDLO/-HI and FP Control/Status reg.) * * Dummy frame layout: * (high memory) * Saved PC * Saved MMHI, MMLO, FPC_CSR * Saved R31 * Saved R28 * ... * Saved R1 * Saved D18 (i.e. F19, F18) * ... * Saved D0 (i.e. F1, F0) * CALL_DUMMY (subroutine stub; see m-mips.h) * Parameter build area (not yet implemented) * (low memory) */ PROC_REG_MASK(proc_desc) = GEN_REG_SAVE_MASK; PROC_FREG_MASK(proc_desc) = FLOAT_REG_SAVE_MASK; PROC_REG_OFFSET(proc_desc) = /* offset of (Saved R31) from FP */ -sizeof(long) - 4 * SPECIAL_REG_SAVE_COUNT; PROC_FREG_OFFSET(proc_desc) = /* offset of (Saved D18) from FP */ -sizeof(double) - 4 * (SPECIAL_REG_SAVE_COUNT + GEN_REG_SAVE_COUNT); /* save general registers */ save_address = sp + PROC_REG_OFFSET(proc_desc); for (ireg = 32; --ireg >= 0; ) if (PROC_REG_MASK(proc_desc) & (1 << ireg)) { buffer = read_register (ireg); write_memory (save_address, &buffer, sizeof(REGISTER_TYPE)); save_address -= 4; } /* save floating-points registers */ save_address = sp + PROC_FREG_OFFSET(proc_desc); for (ireg = 32; --ireg >= 0; ) if (PROC_FREG_MASK(proc_desc) & (1 << ireg)) { buffer = read_register (ireg + FP0_REGNUM); write_memory (save_address, &buffer, 4); save_address -= 4; } write_register (PUSH_FP_REGNUM, sp); PROC_FRAME_REG(proc_desc) = PUSH_FP_REGNUM; PROC_FRAME_OFFSET(proc_desc) = 0; buffer = read_register (PC_REGNUM); write_memory (sp - 4, &buffer, sizeof(REGISTER_TYPE)); buffer = read_register (HI_REGNUM); write_memory (sp - 8, &buffer, sizeof(REGISTER_TYPE)); buffer = read_register (LO_REGNUM); write_memory (sp - 12, &buffer, sizeof(REGISTER_TYPE)); buffer = read_register (FCRCS_REGNUM); write_memory (sp - 16, &buffer, sizeof(REGISTER_TYPE)); sp -= 4 * (GEN_REG_SAVE_COUNT+FLOAT_REG_SAVE_COUNT+SPECIAL_REG_SAVE_COUNT); write_register (SP_REGNUM, sp); PROC_LOW_ADDR(proc_desc) = sp - CALL_DUMMY_SIZE + CALL_DUMMY_START_OFFSET; PROC_HIGH_ADDR(proc_desc) = sp; SET_PROC_DESC_IS_DUMMY(proc_desc); PROC_PC_REG(proc_desc) = RA_REGNUM; } void mips_pop_frame() { register int regnum; FRAME frame = get_current_frame (); CORE_ADDR new_sp = frame->frame; mips_extra_func_info_t proc_desc = (mips_extra_func_info_t)frame->proc_desc; if (PROC_DESC_IS_DUMMY(proc_desc)) { struct linked_proc_info **ptr = &linked_proc_desc_table;; for (; &ptr[0]->info != proc_desc; ptr = &ptr[0]->next ) if (ptr[0] == NULL) abort(); *ptr = ptr[0]->next; free (ptr[0]); write_register (HI_REGNUM, read_memory_integer(new_sp - 8, 4)); write_register (LO_REGNUM, read_memory_integer(new_sp - 12, 4)); write_register (FCRCS_REGNUM, read_memory_integer(new_sp - 16, 4)); } write_register (PC_REGNUM, FRAME_SAVED_PC(frame)); if (frame->proc_desc) { for (regnum = 32; --regnum >= 0; ) if (PROC_REG_MASK(proc_desc) & (1 << regnum)) write_register (regnum, read_memory_integer (frame->saved_regs->regs[regnum], 4)); for (regnum = 32; --regnum >= 0; ) if (PROC_FREG_MASK(proc_desc) & (1 << regnum)) write_register (regnum + FP0_REGNUM, read_memory_integer (frame->saved_regs->regs[regnum + FP0_REGNUM], 4)); } write_register (SP_REGNUM, new_sp); flush_cached_frames (); set_current_frame (create_new_frame (new_sp, read_pc ())); } static mips_print_register(regnum, all) int regnum, all; { unsigned char raw_buffer[8]; REGISTER_TYPE val; read_relative_register_raw_bytes (regnum, raw_buffer); if (!(regnum & 1) && regnum >= FP0_REGNUM && regnum < FP0_REGNUM+32) { read_relative_register_raw_bytes (regnum+1, raw_buffer+4); printf_filtered ("(d%d: ", regnum&31); val_print (builtin_type_double, raw_buffer, 0, stdout, 0, 1, 0, Val_pretty_default); printf_filtered ("); ", regnum&31); } fputs_filtered (reg_names[regnum], stdout); #ifndef NUMERIC_REG_NAMES if (regnum < 32) printf_filtered ("(r%d): ", regnum); else #endif printf_filtered (": "); /* If virtual format is floating, print it that way. */ if (TYPE_CODE (REGISTER_VIRTUAL_TYPE (regnum)) == TYPE_CODE_FLT && ! INVALID_FLOAT (raw_buffer, REGISTER_VIRTUAL_SIZE(regnum))) { val_print (REGISTER_VIRTUAL_TYPE (regnum), raw_buffer, 0, stdout, 0, 1, 0, Val_pretty_default); } /* Else print as integer in hex. */ else { long val; bcopy (raw_buffer, &val, sizeof (long)); if (val == 0) printf_filtered ("0"); else if (all) printf_filtered (local_hex_format(), val); else printf_filtered ("%s=%d", local_hex_string(val), val); } } /* Replacement for generic do_registers_info. */ mips_do_registers_info (regnum, fpregs) int regnum; int fpregs; { if (regnum != -1) { mips_print_register (regnum, 0); printf_filtered ("\n"); } else { for (regnum = 0; regnum < NUM_REGS; ) { if ((!fpregs) && regnum >= FP0_REGNUM && regnum <= FCRIR_REGNUM) { regnum++; continue; } mips_print_register (regnum, 1); regnum++; if ((regnum & 3) == 0 || regnum == NUM_REGS) printf_filtered (";\n"); else printf_filtered ("; "); } } } /* Return number of args passed to a frame. described by FIP. Can return -1, meaning no way to tell. */ mips_frame_num_args(fip) FRAME fip; { #if 0 struct chain_info_t *p; p = mips_find_cached_frame(FRAME_FP(fip)); if (p->valid) return p->the_info.numargs; #endif return -1; } /* Bad floats: Returns 0 if P points to a valid IEEE floating point number, 1 if P points to a denormalized number or a NaN. LEN says whether this is a single-precision or double-precision float */ #define SINGLE_EXP_BITS 8 #define DOUBLE_EXP_BITS 11 int isa_NAN(p, len) int *p, len; { int exponent; if (len == 4) { exponent = *p; exponent = exponent << 1 >> (32 - SINGLE_EXP_BITS - 1); return ((exponent == -1) || (! exponent && *p)); } else if (len == 8) { exponent = *(p+1); exponent = exponent << 1 >> (32 - DOUBLE_EXP_BITS - 1); return ((exponent == -1) || (! exponent && *p * *(p+1))); } else return 1; } /* To skip prologues, I use this predicate. Returns either PC itself if the code at PC does not look like a function prologue, PC+4 if it does (our caller does not need anything more fancy). */ CORE_ADDR mips_skip_prologue(pc) CORE_ADDR pc; { struct symbol *f; struct block *b; unsigned long inst; /* For -g modules and most functions anyways the first instruction adjusts the stack. */ inst = read_memory_integer(pc, 4); if ((inst & 0xffff0000) == 0x27bd0000) return pc + 4; /* Well, it looks like a frameless. Let's make sure. Note that we are not called on the current PC, but on the function`s start PC, and I have definitely seen optimized code that adjusts the SP quite later */ b = block_for_pc(pc); if (!b) return pc; f = lookup_symbol(".gdbinfo.", b, LABEL_NAMESPACE, 0, NULL); if (!f) return pc; /* Ideally, I would like to use the adjusted info from mips_frame_info(), but for all practical purposes it will not matter (and it would require a different definition of SKIP_PROLOGUE()) Actually, it would not hurt to skip the storing of arguments on the stack as well. */ if (((struct mips_extra_func_info *)f->value.value)->framesize) return pc + 4; return pc; }