/* Target-dependent code for the MDEBUG MIPS architecture, for GDB, the GNU Debugger. Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2006 Free Software Foundation, Inc. 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include "defs.h" #include "frame.h" #include "mips-tdep.h" #include "trad-frame.h" #include "block.h" #include "symtab.h" #include "objfiles.h" #include "elf/mips.h" #include "elf-bfd.h" #include "gdb_assert.h" #include "frame-unwind.h" #include "frame-base.h" #include "mips-mdebug-tdep.h" #include "mdebugread.h" #define PROC_LOW_ADDR(proc) ((proc)->pdr.adr) /* least address */ #define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset) #define PROC_FRAME_REG(proc) ((proc)->pdr.framereg) #define PROC_REG_MASK(proc) ((proc)->pdr.regmask) #define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask) #define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset) #define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset) #define PROC_PC_REG(proc) ((proc)->pdr.pcreg) /* FIXME drow/2002-06-10: If a pointer on the host is bigger than a long, this will corrupt pdr.iline. Fortunately we don't use it. */ #define PROC_SYMBOL(proc) (*(struct symbol**)&(proc)->pdr.isym) #define _PROC_MAGIC_ 0x0F0F0F0F struct mips_objfile_private { bfd_size_type size; char *contents; }; /* Global used to communicate between non_heuristic_proc_desc and compare_pdr_entries within qsort (). */ static bfd *the_bfd; static int compare_pdr_entries (const void *a, const void *b) { CORE_ADDR lhs = bfd_get_signed_32 (the_bfd, (bfd_byte *) a); CORE_ADDR rhs = bfd_get_signed_32 (the_bfd, (bfd_byte *) b); if (lhs < rhs) return -1; else if (lhs == rhs) return 0; else return 1; } static const struct objfile_data *mips_pdr_data; static struct mdebug_extra_func_info * non_heuristic_proc_desc (CORE_ADDR pc, CORE_ADDR *addrptr) { CORE_ADDR startaddr; struct mdebug_extra_func_info *proc_desc; struct block *b = block_for_pc (pc); struct symbol *sym; struct obj_section *sec; struct mips_objfile_private *priv; find_pc_partial_function (pc, NULL, &startaddr, NULL); if (addrptr) *addrptr = startaddr; priv = NULL; sec = find_pc_section (pc); if (sec != NULL) { priv = (struct mips_objfile_private *) objfile_data (sec->objfile, mips_pdr_data); /* Search the ".pdr" section generated by GAS. This includes most of the information normally found in ECOFF PDRs. */ the_bfd = sec->objfile->obfd; if (priv == NULL && (the_bfd->format == bfd_object && bfd_get_flavour (the_bfd) == bfd_target_elf_flavour && elf_elfheader (the_bfd)->e_ident[EI_CLASS] == ELFCLASS64)) { /* Right now GAS only outputs the address as a four-byte sequence. This means that we should not bother with this method on 64-bit targets (until that is fixed). */ priv = obstack_alloc (&sec->objfile->objfile_obstack, sizeof (struct mips_objfile_private)); priv->size = 0; set_objfile_data (sec->objfile, mips_pdr_data, priv); } else if (priv == NULL) { asection *bfdsec; priv = obstack_alloc (&sec->objfile->objfile_obstack, sizeof (struct mips_objfile_private)); bfdsec = bfd_get_section_by_name (sec->objfile->obfd, ".pdr"); if (bfdsec != NULL) { priv->size = bfd_section_size (sec->objfile->obfd, bfdsec); priv->contents = obstack_alloc (&sec->objfile->objfile_obstack, priv->size); bfd_get_section_contents (sec->objfile->obfd, bfdsec, priv->contents, 0, priv->size); /* In general, the .pdr section is sorted. However, in the presence of multiple code sections (and other corner cases) it can become unsorted. Sort it so that we can use a faster binary search. */ qsort (priv->contents, priv->size / 32, 32, compare_pdr_entries); } else priv->size = 0; set_objfile_data (sec->objfile, mips_pdr_data, priv); } the_bfd = NULL; if (priv->size != 0) { int low, mid, high; char *ptr; CORE_ADDR pdr_pc; low = 0; high = priv->size / 32; /* We've found a .pdr section describing this objfile. We want to find the entry which describes this code address. The .pdr information is not very descriptive; we have only a function start address. We have to look for the closest entry, because the local symbol at the beginning of this function may have been stripped - so if we ask the symbol table for the start address we may get a preceding global function. */ /* First, find the last .pdr entry starting at or before PC. */ do { mid = (low + high) / 2; ptr = priv->contents + mid * 32; pdr_pc = bfd_get_signed_32 (sec->objfile->obfd, ptr); pdr_pc += ANOFFSET (sec->objfile->section_offsets, SECT_OFF_TEXT (sec->objfile)); if (pdr_pc > pc) high = mid; else low = mid + 1; } while (low != high); /* Both low and high point one past the PDR of interest. If both are zero, that means this PC is before any region covered by a PDR, i.e. pdr_pc for the first PDR entry is greater than PC. */ if (low > 0) { ptr = priv->contents + (low - 1) * 32; pdr_pc = bfd_get_signed_32 (sec->objfile->obfd, ptr); pdr_pc += ANOFFSET (sec->objfile->section_offsets, SECT_OFF_TEXT (sec->objfile)); } /* We don't have a range, so we have no way to know for sure whether we're in the correct PDR or a PDR for a preceding function and the current function was a stripped local symbol. But if the PDR's PC is at least as great as the best guess from the symbol table, assume that it does cover the right area; if a .pdr section is present at all then nearly every function will have an entry. The biggest exception will be the dynamic linker stubs; conveniently these are placed before .text instead of after. */ if (pc >= pdr_pc && pdr_pc >= startaddr) { struct symbol *sym = find_pc_function (pc); if (addrptr) *addrptr = pdr_pc; /* Fill in what we need of the proc_desc. */ proc_desc = (struct mdebug_extra_func_info *) obstack_alloc (&sec->objfile->objfile_obstack, sizeof (struct mdebug_extra_func_info)); PROC_LOW_ADDR (proc_desc) = pdr_pc; PROC_FRAME_OFFSET (proc_desc) = bfd_get_signed_32 (sec->objfile->obfd, ptr + 20); PROC_FRAME_REG (proc_desc) = bfd_get_32 (sec->objfile->obfd, ptr + 24); PROC_REG_MASK (proc_desc) = bfd_get_32 (sec->objfile->obfd, ptr + 4); PROC_FREG_MASK (proc_desc) = bfd_get_32 (sec->objfile->obfd, ptr + 12); PROC_REG_OFFSET (proc_desc) = bfd_get_signed_32 (sec->objfile->obfd, ptr + 8); PROC_FREG_OFFSET (proc_desc) = bfd_get_signed_32 (sec->objfile->obfd, ptr + 16); PROC_PC_REG (proc_desc) = bfd_get_32 (sec->objfile->obfd, ptr + 28); proc_desc->pdr.isym = (long) sym; return proc_desc; } } } if (b == NULL) return NULL; if (startaddr > BLOCK_START (b)) { /* This is the "pathological" case referred to in a comment in print_frame_info. It might be better to move this check into symbol reading. */ return NULL; } sym = lookup_symbol (MDEBUG_EFI_SYMBOL_NAME, b, LABEL_DOMAIN, 0, NULL); /* If we never found a PDR for this function in symbol reading, then examine prologues to find the information. */ if (sym) { proc_desc = (struct mdebug_extra_func_info *) SYMBOL_VALUE (sym); if (PROC_FRAME_REG (proc_desc) == -1) return NULL; else return proc_desc; } else return NULL; } struct mips_frame_cache { CORE_ADDR base; struct trad_frame_saved_reg *saved_regs; }; static struct mips_frame_cache * mips_mdebug_frame_cache (struct frame_info *next_frame, void **this_cache) { CORE_ADDR startaddr = 0; struct mdebug_extra_func_info *proc_desc; struct mips_frame_cache *cache; struct gdbarch *gdbarch = get_frame_arch (next_frame); struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); /* r0 bit means kernel trap */ int kernel_trap; /* What registers have been saved? Bitmasks. */ unsigned long gen_mask, float_mask; if ((*this_cache) != NULL) return (*this_cache); cache = FRAME_OBSTACK_ZALLOC (struct mips_frame_cache); (*this_cache) = cache; cache->saved_regs = trad_frame_alloc_saved_regs (next_frame); /* Get the mdebug proc descriptor. */ proc_desc = non_heuristic_proc_desc (frame_pc_unwind (next_frame), &startaddr); /* Must be true. This is only called when the sniffer detected a proc descriptor. */ gdb_assert (proc_desc != NULL); /* Extract the frame's base. */ cache->base = (frame_unwind_register_signed (next_frame, NUM_REGS + PROC_FRAME_REG (proc_desc)) + PROC_FRAME_OFFSET (proc_desc)); kernel_trap = PROC_REG_MASK (proc_desc) & 1; gen_mask = kernel_trap ? 0xFFFFFFFF : PROC_REG_MASK (proc_desc); float_mask = kernel_trap ? 0xFFFFFFFF : PROC_FREG_MASK (proc_desc); /* Must be true. The in_prologue case is left for the heuristic unwinder. This is always used on kernel traps. */ gdb_assert (!in_prologue (frame_pc_unwind (next_frame), PROC_LOW_ADDR (proc_desc)) || kernel_trap); /* Fill in the offsets for the registers which gen_mask says were saved. */ { CORE_ADDR reg_position = (cache->base + PROC_REG_OFFSET (proc_desc)); int ireg; for (ireg = MIPS_NUMREGS - 1; gen_mask; --ireg, gen_mask <<= 1) if (gen_mask & 0x80000000) { cache->saved_regs[NUM_REGS + ireg].addr = reg_position; reg_position -= mips_abi_regsize (gdbarch); } } /* Fill in the offsets for the registers which float_mask says were saved. */ { CORE_ADDR reg_position = (cache->base + PROC_FREG_OFFSET (proc_desc)); int ireg; /* Fill in the offsets for the float registers which float_mask says were saved. */ for (ireg = MIPS_NUMREGS - 1; float_mask; --ireg, float_mask <<= 1) if (float_mask & 0x80000000) { if (mips_abi_regsize (gdbarch) == 4 && TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) { /* On a big endian 32 bit ABI, floating point registers are paired to form doubles such that the most significant part is in $f[N+1] and the least significant in $f[N] vis: $f[N+1] ||| $f[N]. The registers are also spilled as a pair and stored as a double. When little-endian the least significant part is stored first leading to the memory order $f[N] and then $f[N+1]. Unfortunately, when big-endian the most significant part of the double is stored first, and the least significant is stored second. This leads to the registers being ordered in memory as firt $f[N+1] and then $f[N]. For the big-endian case make certain that the addresses point at the correct (swapped) locations $f[N] and $f[N+1] pair (keep in mind that reg_position is decremented each time through the loop). */ if ((ireg & 1)) cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->fp0 + ireg] .addr = reg_position - mips_abi_regsize (gdbarch); else cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->fp0 + ireg] .addr = reg_position + mips_abi_regsize (gdbarch); } else cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->fp0 + ireg] .addr = reg_position; reg_position -= mips_abi_regsize (gdbarch); } cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->pc] = cache->saved_regs[NUM_REGS + MIPS_RA_REGNUM]; } /* SP_REGNUM, contains the value and not the address. */ trad_frame_set_value (cache->saved_regs, NUM_REGS + MIPS_SP_REGNUM, cache->base); return (*this_cache); } static void mips_mdebug_frame_this_id (struct frame_info *next_frame, void **this_cache, struct frame_id *this_id) { struct mips_frame_cache *info = mips_mdebug_frame_cache (next_frame, this_cache); (*this_id) = frame_id_build (info->base, frame_func_unwind (next_frame)); } static void mips_mdebug_frame_prev_register (struct frame_info *next_frame, void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp, CORE_ADDR *addrp, int *realnump, void *valuep) { struct mips_frame_cache *info = mips_mdebug_frame_cache (next_frame, this_cache); trad_frame_get_prev_register (next_frame, info->saved_regs, regnum, optimizedp, lvalp, addrp, realnump, valuep); } static const struct frame_unwind mips_mdebug_frame_unwind = { NORMAL_FRAME, mips_mdebug_frame_this_id, mips_mdebug_frame_prev_register }; static const struct frame_unwind * mips_mdebug_frame_sniffer (struct frame_info *next_frame) { CORE_ADDR pc = frame_pc_unwind (next_frame); CORE_ADDR startaddr = 0; struct mdebug_extra_func_info *proc_desc; int kernel_trap; /* Don't use this on MIPS16. */ if (mips_pc_is_mips16 (pc)) return NULL; /* Only use the mdebug frame unwinder on mdebug frames where all the registers have been saved. Leave hard cases such as no mdebug or in prologue for the heuristic unwinders. */ proc_desc = non_heuristic_proc_desc (pc, &startaddr); if (proc_desc == NULL) return NULL; /* Not sure exactly what kernel_trap means, but if it means the kernel saves the registers without a prologue doing it, we better not examine the prologue to see whether registers have been saved yet. */ kernel_trap = PROC_REG_MASK (proc_desc) & 1; if (kernel_trap) return &mips_mdebug_frame_unwind; /* In any frame other than the innermost or a frame interrupted by a signal, we assume that all registers have been saved. This assumes that all register saves in a function happen before the first function call. */ if (!in_prologue (pc, PROC_LOW_ADDR (proc_desc))) return &mips_mdebug_frame_unwind; return NULL; } static CORE_ADDR mips_mdebug_frame_base_address (struct frame_info *next_frame, void **this_cache) { struct mips_frame_cache *info = mips_mdebug_frame_cache (next_frame, this_cache); return info->base; } static const struct frame_base mips_mdebug_frame_base = { &mips_mdebug_frame_unwind, mips_mdebug_frame_base_address, mips_mdebug_frame_base_address, mips_mdebug_frame_base_address }; static const struct frame_base * mips_mdebug_frame_base_sniffer (struct frame_info *next_frame) { if (mips_mdebug_frame_sniffer (next_frame) != NULL) return &mips_mdebug_frame_base; else return NULL; } void mips_mdebug_append_sniffers (struct gdbarch *gdbarch) { frame_unwind_append_sniffer (gdbarch, mips_mdebug_frame_sniffer); frame_base_append_sniffer (gdbarch, mips_mdebug_frame_base_sniffer); } extern void _initialize_mips_mdebug_tdep (void); void _initialize_mips_mdebug_tdep (void) { mips_pdr_data = register_objfile_data (); }