/* 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 #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 #include 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 */ } /* Flush the frame cache, and start a new one if necessary. */ void reinit_frame_cache () { FRAME fr = current_frame; flush_cached_frames (); if (fr) set_current_frame ( create_new_frame (read_register (FP_REGNUM), read_pc ())); } /* 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 /* && 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); }