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Diffstat (limited to 'gdb/blockframe.c')
| -rw-r--r-- | gdb/blockframe.c | 650 |
1 files changed, 650 insertions, 0 deletions
diff --git a/gdb/blockframe.c b/gdb/blockframe.c new file mode 100644 index 00000000000..7971166a3c0 --- /dev/null +++ b/gdb/blockframe.c @@ -0,0 +1,650 @@ +/* Get info from stack frames; + convert between frames, blocks, functions and pc values. + Copyright (C) 1986, 1987, 1988, 1989 Free Software Foundation, Inc. + +This file is part of GDB. + +GDB 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 1, or (at your option) +any later version. + +GDB 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 GDB; see the file COPYING. If not, write to +the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ + +#include "defs.h" +#include "param.h" +#include "symtab.h" +#include "frame.h" +#include "gdbcore.h" +#include "value.h" /* for read_register */ +#include "target.h" /* for target_has_stack */ + +/* Required by INIT_EXTRA_FRAME_INFO on 88k. */ +#include <setjmp.h> +#include <obstack.h> + +CORE_ADDR read_pc (); /* In infcmd.c */ + +/* Start and end of object file containing the entry point. + STARTUP_FILE_END is the first address of the next file. + This file is assumed to be a startup file + and frames with pc's inside it + are treated as nonexistent. + + Setting these variables is necessary so that backtraces do not fly off + the bottom of the stack. */ +CORE_ADDR startup_file_start; +CORE_ADDR startup_file_end; + +/* Is ADDR outside the startup file? Note that if your machine + has a way to detect the bottom of the stack, there is no need + to call this function from FRAME_CHAIN_VALID; the reason for + doing so is that some machines have no way of detecting bottom + of stack. */ +int +outside_startup_file (addr) + CORE_ADDR addr; +{ + return !(addr >= startup_file_start && addr < startup_file_end); +} + +/* Address of innermost stack frame (contents of FP register) */ + +static FRAME current_frame; + +/* + * Cache for frame addresses already read by gdb. Valid only while + * inferior is stopped. Control variables for the frame cache should + * be local to this module. + */ +struct obstack frame_cache_obstack; + +/* Return the innermost (currently executing) stack frame. */ + +FRAME +get_current_frame () +{ + /* We assume its address is kept in a general register; + param.h says which register. */ + + return current_frame; +} + +void +set_current_frame (frame) + FRAME frame; +{ + current_frame = frame; +} + +FRAME +create_new_frame (addr, pc) + FRAME_ADDR addr; + CORE_ADDR pc; +{ + struct frame_info *fci; /* Same type as FRAME */ + + fci = (struct frame_info *) + obstack_alloc (&frame_cache_obstack, + sizeof (struct frame_info)); + + /* Arbitrary frame */ + fci->next = (struct frame_info *) 0; + fci->prev = (struct frame_info *) 0; + fci->frame = addr; + fci->next_frame = 0; /* Since arbitrary */ + fci->pc = pc; + +#ifdef INIT_EXTRA_FRAME_INFO + INIT_EXTRA_FRAME_INFO (fci); +#endif + + return fci; +} + +/* Return the frame that called FRAME. + If FRAME is the original frame (it has no caller), return 0. */ + +FRAME +get_prev_frame (frame) + FRAME frame; +{ + /* We're allowed to know that FRAME and "struct frame_info *" are + the same */ + return get_prev_frame_info (frame); +} + +/* Return the frame that FRAME calls (0 if FRAME is the innermost + frame). */ + +FRAME +get_next_frame (frame) + FRAME frame; +{ + /* We're allowed to know that FRAME and "struct frame_info *" are + the same */ + return frame->next; +} + +/* + * Flush the entire frame cache. + */ +void +flush_cached_frames () +{ + /* Since we can't really be sure what the first object allocated was */ + obstack_free (&frame_cache_obstack, 0); + obstack_init (&frame_cache_obstack); + + current_frame = (struct frame_info *) 0; /* Invalidate cache */ +} + +/* Return a structure containing various interesting information + about a specified stack frame. */ +/* How do I justify including this function? Well, the FRAME + identifier format has gone through several changes recently, and + it's not completely inconceivable that it could happen again. If + it does, have this routine around will help */ + +struct frame_info * +get_frame_info (frame) + FRAME frame; +{ + return frame; +} + +/* If a machine allows frameless functions, it should define a macro + FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) in param.h. FI is the struct + frame_info for the frame, and FRAMELESS should be set to nonzero + if it represents a frameless function invocation. */ + +/* Return nonzero if the function for this frame has a prologue. Many + machines can define FRAMELESS_FUNCTION_INVOCATION to just call this + function. */ + +int +frameless_look_for_prologue (frame) + FRAME frame; +{ + CORE_ADDR func_start, after_prologue; + func_start = (get_pc_function_start (frame->pc) + + FUNCTION_START_OFFSET); + if (func_start) + { + after_prologue = func_start; + SKIP_PROLOGUE (after_prologue); + return after_prologue == func_start; + } + else + /* If we can't find the start of the function, we don't really + know whether the function is frameless, but we should be able + to get a reasonable (i.e. best we can do under the + circumstances) backtrace by saying that it isn't. */ + return 0; +} + +#if !defined (INIT_FRAME_PC) +#define INIT_FRAME_PC(fromleaf, prev) \ + prev->pc = (fromleaf ? SAVED_PC_AFTER_CALL (prev->next) : \ + prev->next ? FRAME_SAVED_PC (prev->next) : read_pc ()); +#endif + +/* Return a structure containing various interesting information + about the frame that called NEXT_FRAME. Returns NULL + if there is no such frame. */ + +struct frame_info * +get_prev_frame_info (next_frame) + FRAME next_frame; +{ + FRAME_ADDR address; + struct frame_info *prev; + int fromleaf = 0; + + /* If the requested entry is in the cache, return it. + Otherwise, figure out what the address should be for the entry + we're about to add to the cache. */ + + if (!next_frame) + { + if (!current_frame) + { + error ("You haven't set up a process's stack to examine."); + } + + return current_frame; + } + + /* If we have the prev one, return it */ + if (next_frame->prev) + return next_frame->prev; + + /* On some machines it is possible to call a function without + setting up a stack frame for it. On these machines, we + define this macro to take two args; a frameinfo pointer + identifying a frame and a variable to set or clear if it is + or isn't leafless. */ +#ifdef FRAMELESS_FUNCTION_INVOCATION + /* Still don't want to worry about this except on the innermost + frame. This macro will set FROMLEAF if NEXT_FRAME is a + frameless function invocation. */ + if (!(next_frame->next)) + { + FRAMELESS_FUNCTION_INVOCATION (next_frame, fromleaf); + if (fromleaf) + address = next_frame->frame; + } +#endif + + if (!fromleaf) + { + /* Two macros defined in tm.h specify the machine-dependent + actions to be performed here. + First, get the frame's chain-pointer. + If that is zero, the frame is the outermost frame or a leaf + called by the outermost frame. This means that if start + calls main without a frame, we'll return 0 (which is fine + anyway). + + Nope; there's a problem. This also returns when the current + routine is a leaf of main. This is unacceptable. We move + this to after the ffi test; I'd rather have backtraces from + start go curfluy than have an abort called from main not show + main. */ + address = FRAME_CHAIN (next_frame); + if (!FRAME_CHAIN_VALID (address, next_frame)) + return 0; + address = FRAME_CHAIN_COMBINE (address, next_frame); + } + + prev = (struct frame_info *) + obstack_alloc (&frame_cache_obstack, + sizeof (struct frame_info)); + + if (next_frame) + next_frame->prev = prev; + prev->next = next_frame; + prev->prev = (struct frame_info *) 0; + prev->frame = address; + prev->next_frame = prev->next ? prev->next->frame : 0; + +#ifdef INIT_EXTRA_FRAME_INFO + INIT_EXTRA_FRAME_INFO(prev); +#endif + + /* This entry is in the frame queue now, which is good since + FRAME_SAVED_PC may use that queue to figure out it's value + (see m-sparc.h). We want the pc saved in the inferior frame. */ + INIT_FRAME_PC(fromleaf, prev); + + return prev; +} + +CORE_ADDR +get_frame_pc (frame) + FRAME frame; +{ + struct frame_info *fi; + fi = get_frame_info (frame); + return fi->pc; +} + +#if defined (FRAME_FIND_SAVED_REGS) +/* Find the addresses in which registers are saved in FRAME. */ + +void +get_frame_saved_regs (frame_info_addr, saved_regs_addr) + struct frame_info *frame_info_addr; + struct frame_saved_regs *saved_regs_addr; +{ + FRAME_FIND_SAVED_REGS (frame_info_addr, *saved_regs_addr); +} +#endif + +/* Return the innermost lexical block in execution + in a specified stack frame. The frame address is assumed valid. */ + +struct block * +get_frame_block (frame) + FRAME frame; +{ + struct frame_info *fi; + CORE_ADDR pc; + + fi = get_frame_info (frame); + + pc = fi->pc; + if (fi->next_frame != 0) + /* We are not in the innermost frame. We need to subtract one to + get the correct block, in case the call instruction was the + last instruction of the block. If there are any machines on + which the saved pc does not point to after the call insn, we + probably want to make fi->pc point after the call insn anyway. */ + --pc; + return block_for_pc (pc); +} + +struct block * +get_current_block () +{ + return block_for_pc (read_pc ()); +} + +CORE_ADDR +get_pc_function_start (pc) + CORE_ADDR pc; +{ + register struct block *bl = block_for_pc (pc); + register struct symbol *symbol; + if (bl == 0 || (symbol = block_function (bl)) == 0) + { + register int misc_index = find_pc_misc_function (pc); + if (misc_index >= 0) + return misc_function_vector[misc_index].address; + return 0; + } + bl = SYMBOL_BLOCK_VALUE (symbol); + return BLOCK_START (bl); +} + +/* Return the symbol for the function executing in frame FRAME. */ + +struct symbol * +get_frame_function (frame) + FRAME frame; +{ + register struct block *bl = get_frame_block (frame); + if (bl == 0) + return 0; + return block_function (bl); +} + +/* Return the blockvector immediately containing the innermost lexical block + containing the specified pc value, or 0 if there is none. + PINDEX is a pointer to the index value of the block. If PINDEX + is NULL, we don't pass this information back to the caller. */ + +struct blockvector * +blockvector_for_pc (pc, pindex) + register CORE_ADDR pc; + int *pindex; +{ + register struct block *b; + register int bot, top, half; + register struct symtab *s; + struct blockvector *bl; + + /* First search all symtabs for one whose file contains our pc */ + s = find_pc_symtab (pc); + if (s == 0) + return 0; + + bl = BLOCKVECTOR (s); + b = BLOCKVECTOR_BLOCK (bl, 0); + + /* Then search that symtab for the smallest block that wins. */ + /* Use binary search to find the last block that starts before PC. */ + + bot = 0; + top = BLOCKVECTOR_NBLOCKS (bl); + + while (top - bot > 1) + { + half = (top - bot + 1) >> 1; + b = BLOCKVECTOR_BLOCK (bl, bot + half); + if (BLOCK_START (b) <= pc) + bot += half; + else + top = bot + half; + } + + /* Now search backward for a block that ends after PC. */ + + while (bot >= 0) + { + b = BLOCKVECTOR_BLOCK (bl, bot); + if (BLOCK_END (b) > pc) + { + if (pindex) + *pindex = bot; + return bl; + } + bot--; + } + + return 0; +} + +/* Return the innermost lexical block containing the specified pc value, + or 0 if there is none. */ + +struct block * +block_for_pc (pc) + register CORE_ADDR pc; +{ + register struct blockvector *bl; + int index; + + bl = blockvector_for_pc (pc, &index); + if (bl) + return BLOCKVECTOR_BLOCK (bl, index); + return 0; +} + +/* Return the function containing pc value PC. + Returns 0 if function is not known. */ + +struct symbol * +find_pc_function (pc) + CORE_ADDR pc; +{ + register struct block *b = block_for_pc (pc); + if (b == 0) + return 0; + return block_function (b); +} + +/* These variables are used to cache the most recent result + * of find_pc_partial_function. */ + +static CORE_ADDR cache_pc_function_low = 0; +static CORE_ADDR cache_pc_function_high = 0; +static char *cache_pc_function_name = 0; + +/* Clear cache, e.g. when symbol table is discarded. */ + +void +clear_pc_function_cache() +{ + cache_pc_function_low = 0; + cache_pc_function_high = 0; + cache_pc_function_name = (char *)0; +} + +/* Finds the "function" (text symbol) that is smaller than PC + but greatest of all of the potential text symbols. Sets + *NAME and/or *ADDRESS conditionally if that pointer is non-zero. + Returns 0 if it couldn't find anything, 1 if it did. On a zero + return, *NAME and *ADDRESS are always set to zero. On a 1 return, + *NAME and *ADDRESS contain real information. */ + +int +find_pc_partial_function (pc, name, address) + CORE_ADDR pc; + char **name; + CORE_ADDR *address; +{ + struct partial_symtab *pst; + struct symbol *f; + int miscfunc; + struct partial_symbol *psb; + + if (pc >= cache_pc_function_low && pc < cache_pc_function_high) + { + if (address) + *address = cache_pc_function_low; + if (name) + *name = cache_pc_function_name; + return 1; + } + + pst = find_pc_psymtab (pc); + if (pst) + { + if (pst->readin) + { + /* The information we want has already been read in. + We can go to the already readin symbols and we'll get + the best possible answer. */ + f = find_pc_function (pc); + if (!f) + { + return_error: + /* No available symbol. */ + if (name != 0) + *name = 0; + if (address != 0) + *address = 0; + return 0; + } + + cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f)); + cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f)); + cache_pc_function_name = SYMBOL_NAME (f); + if (name) + *name = cache_pc_function_name; + if (address) + *address = cache_pc_function_low; + return 1; + } + + /* Get the information from a combination of the pst + (static symbols), and the misc function vector (extern + symbols). */ + miscfunc = find_pc_misc_function (pc); + psb = find_pc_psymbol (pst, pc); + + if (!psb && miscfunc == -1) + { + goto return_error; + } + if (psb + && (miscfunc == -1 + || (SYMBOL_VALUE_ADDRESS (psb) + >= misc_function_vector[miscfunc].address))) + { + /* This case isn't being cached currently. */ + if (address) + *address = SYMBOL_VALUE_ADDRESS (psb); + if (name) + *name = SYMBOL_NAME (psb); + return 1; + } + } + else + /* Must be in the misc function stuff. */ + { + miscfunc = find_pc_misc_function (pc); + if (miscfunc == -1) + goto return_error; + } + + { + if (misc_function_vector[miscfunc].type == mf_text) + cache_pc_function_low = misc_function_vector[miscfunc].address; + else + /* It is a transfer table for Sun shared libraries. */ + cache_pc_function_low = pc - FUNCTION_START_OFFSET; + } + cache_pc_function_name = misc_function_vector[miscfunc].name; + if (miscfunc < misc_function_count && 1 /* FIXME mf_text again? */ ) + cache_pc_function_high = misc_function_vector[miscfunc+1].address; + else + cache_pc_function_high = cache_pc_function_low + 1; + if (address) + *address = cache_pc_function_low; + if (name) + *name = cache_pc_function_name; + return 1; +} + +/* Find the misc function whose address is the largest + while being less than PC. Return its index in misc_function_vector. + Returns -1 if PC is not in suitable range. */ + +int +find_pc_misc_function (pc) + register CORE_ADDR pc; +{ + register int lo = 0; + register int hi = misc_function_count-1; + register int new; + + /* Note that the last thing in the vector is always _etext. */ + /* Actually, "end", now that non-functions + go on the misc_function_vector. */ + + /* Above statement is not *always* true - fix for case where there are */ + /* no misc functions at all (ie no symbol table has been read). */ + if (hi < 0) return -1; /* no misc functions recorded */ + + /* trivial reject range test */ + if (pc < misc_function_vector[0].address || + pc > misc_function_vector[hi].address) + return -1; + + /* Note that the following search will not return hi if + pc == misc_function_vector[hi].address. If "end" points to the + first unused location, this is correct and the above test + simply needs to be changed to + "pc >= misc_function_vector[hi].address". */ + do { + new = (lo + hi) >> 1; + if (misc_function_vector[new].address == pc) + return new; /* an exact match */ + else if (misc_function_vector[new].address > pc) + hi = new; + else + lo = new; + } while (hi-lo != 1); + + /* if here, we had no exact match, so return the lower choice */ + return lo; +} + +/* Return the innermost stack frame executing inside of the specified block, + or zero if there is no such frame. */ + +FRAME +block_innermost_frame (block) + struct block *block; +{ + struct frame_info *fi; + register FRAME frame; + register CORE_ADDR start = BLOCK_START (block); + register CORE_ADDR end = BLOCK_END (block); + + frame = 0; + while (1) + { + frame = get_prev_frame (frame); + if (frame == 0) + return 0; + fi = get_frame_info (frame); + if (fi->pc >= start && fi->pc < end) + return frame; + } +} + +void +_initialize_blockframe () +{ + obstack_init (&frame_cache_obstack); +} |