/* Get info from stack frames; convert between frames, blocks, functions and pc values. Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "defs.h" #include "symtab.h" #include "bfd.h" #include "symfile.h" #include "objfiles.h" #include "frame.h" #include "gdbcore.h" #include "value.h" /* for read_register */ #include "target.h" /* for target_has_stack */ #include "inferior.h" /* for read_pc */ #include "annotate.h" #include "regcache.h" #include "gdb_assert.h" #include "dummy-frame.h" #include "command.h" #include "gdbcmd.h" /* Prototypes for exported functions. */ void _initialize_blockframe (void); /* Is ADDR inside 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. A PC of zero is always considered to be the bottom of the stack. APPLE LOCAL: Don't treat a PC of zero as the bottom of the stack. If you do, then you won't give a backtrace if somebody calls a NULL function pointer. */ int inside_entry_file (CORE_ADDR addr) { #if 0 if (addr == 0) return 1; #endif if (symfile_objfile == 0) return 0; if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT) { /* Do not stop backtracing if the pc is in the call dummy at the entry point. */ /* FIXME: Won't always work with zeros for the last two arguments */ if (DEPRECATED_PC_IN_CALL_DUMMY (addr, 0, 0)) return 0; } return (addr >= symfile_objfile->ei.entry_file_lowpc && addr < symfile_objfile->ei.entry_file_highpc); } /* Test a specified PC value to see if it is in the range of addresses that correspond to the main() function. See comments above for why we might want to do this. Typically called from FRAME_CHAIN_VALID. A PC of zero is always considered to be the bottom of the stack. APPLE LOCAL: Don't treat a PC of zero as the bottom of the stack. If you do, then you won't give a backtrace if somebody calls a NULL function pointer. */ int inside_main_func (CORE_ADDR pc) { #if 0 if (pc == 0) return 1; #endif if (symfile_objfile == 0) return 0; /* If the addr range is not set up at symbol reading time, set it up now. This is for FRAME_CHAIN_VALID_ALTERNATE. I do this for coff, because it is unable to set it up and symbol reading time. */ if (symfile_objfile->ei.main_func_lowpc == INVALID_ENTRY_LOWPC && symfile_objfile->ei.main_func_highpc == INVALID_ENTRY_HIGHPC) { struct symbol *mainsym; mainsym = lookup_symbol (main_name (), NULL, VAR_NAMESPACE, NULL, NULL); if (mainsym && SYMBOL_CLASS (mainsym) == LOC_BLOCK) { symfile_objfile->ei.main_func_lowpc = BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym)); symfile_objfile->ei.main_func_highpc = BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym)); } } return (symfile_objfile->ei.main_func_lowpc <= pc && symfile_objfile->ei.main_func_highpc > pc); } /* Test a specified PC value to see if it is in the range of addresses that correspond to the process entry point function. See comments in objfiles.h for why we might want to do this. Typically called from FRAME_CHAIN_VALID. A PC of zero is always considered to be the bottom of the stack. APPLE LOCAL: Don't treat a PC of zero as the bottom of the stack. If you do, then you won't give a backtrace if somebody calls a NULL function pointer. */ int inside_entry_func (CORE_ADDR pc) { #if 0 if (pc == 0) return 1; #endif if (symfile_objfile == 0) return 0; if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT) { /* Do not stop backtracing if the pc is in the call dummy at the entry point. */ /* FIXME: Won't always work with zeros for the last two arguments */ if (DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0)) return 0; } return (symfile_objfile->ei.entry_func_lowpc <= pc && symfile_objfile->ei.entry_func_highpc > pc); } /* Return nonzero if the function for this frame lacks a prologue. Many machines can define FRAMELESS_FUNCTION_INVOCATION to just call this function. */ int frameless_look_for_prologue (struct frame_info *frame) { CORE_ADDR func_start, after_prologue; func_start = get_pc_function_start (get_frame_pc (frame)); if (func_start) { func_start += FUNCTION_START_OFFSET; /* This is faster, since only care whether there *is* a prologue, not how long it is. */ return PROLOGUE_FRAMELESS_P (func_start); } else if (get_frame_pc (frame) == 0) /* A frame with a zero PC is usually created by dereferencing a NULL function pointer, normally causing an immediate core dump of the inferior. Mark function as frameless, as the inferior has no chance of setting up a stack frame. */ return 1; 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; } /* return the address of the PC for the given FRAME, ie the current PC value if FRAME is the innermost frame, or the address adjusted to point to the call instruction if not. */ CORE_ADDR frame_address_in_block (struct frame_info *frame) { CORE_ADDR pc = get_frame_pc (frame); /* If we are not in the innermost frame, and we are not interrupted by a signal, frame->pc points to the instruction following the call. As a consequence, we need to get the address of the previous instruction. Unfortunately, this is not straightforward to do, so we just use the address minus one, which is a good enough approximation. */ /* FIXME: cagney/2002-11-10: Should this instead test for NORMAL_FRAME? A dummy frame (in fact all the abnormal frames) save the PC value in the block. */ if (get_next_frame (frame) != 0 && get_frame_type (get_next_frame (frame)) != SIGTRAMP_FRAME) --pc; return pc; } /* Return the innermost lexical block in execution in a specified stack frame. The frame address is assumed valid. If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code address we used to choose the block. We use this to find a source line, to decide which macro definitions are in scope. The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's PC, and may not really be a valid PC at all. For example, in the caller of a function declared to never return, the code at the return address will never be reached, so the call instruction may be the very last instruction in the block. So the address we use to choose the block is actually one byte before the return address --- hopefully pointing us at the call instruction, or its delay slot instruction. */ struct block * get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block) { const CORE_ADDR pc = frame_address_in_block (frame); if (addr_in_block) *addr_in_block = pc; return block_for_pc (pc); } CORE_ADDR get_pc_function_start (CORE_ADDR pc) { register struct block *bl; register struct symbol *symbol; register struct minimal_symbol *msymbol; CORE_ADDR fstart; if ((bl = block_for_pc (pc)) != NULL && (symbol = block_function (bl)) != NULL) { bl = SYMBOL_BLOCK_VALUE (symbol); fstart = BLOCK_START (bl); } else if ((msymbol = lookup_minimal_symbol_by_pc (pc)) != NULL) { fstart = SYMBOL_VALUE_ADDRESS (msymbol); if (!find_pc_section (fstart)) return 0; } else { fstart = 0; } return (fstart); } /* Return the symbol for the function executing in frame FRAME. */ struct symbol * get_frame_function (struct frame_info *frame) { register struct block *bl = get_frame_block (frame, 0); if (bl == 0) return 0; return block_function (bl); } /* Return the blockvector immediately containing the innermost lexical block containing the specified pc value and section, 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_sect (register CORE_ADDR pc, struct sec *section, int *pindex, struct symtab *symtab) { register struct block *b; register int bot, top, half; struct blockvector *bl; if (symtab == 0) /* if no symtab specified by caller */ { /* First search all symtabs for one whose file contains our pc */ if ((symtab = find_pc_sect_symtab (pc, section)) == 0) return 0; } bl = BLOCKVECTOR (symtab); 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 blockvector immediately containing the innermost lexical block containing the specified pc value, or 0 if there is none. Backward compatibility, no section. */ struct blockvector * blockvector_for_pc (register CORE_ADDR pc, int *pindex) { return blockvector_for_pc_sect (pc, find_pc_mapped_section (pc), pindex, NULL); } /* Return the innermost lexical block containing the specified pc value in the specified section, or 0 if there is none. */ struct block * block_for_pc_sect (register CORE_ADDR pc, struct sec *section) { register struct blockvector *bl; int index; bl = blockvector_for_pc_sect (pc, section, &index, NULL); if (bl) return BLOCKVECTOR_BLOCK (bl, index); return 0; } /* Return the innermost lexical block containing the specified pc value, or 0 if there is none. Backward compatibility, no section. */ struct block * block_for_pc (register CORE_ADDR pc) { return block_for_pc_sect (pc, find_pc_mapped_section (pc)); } /* Return the function containing pc value PC in section SECTION. Returns 0 if function is not known. */ struct symbol * find_pc_sect_function (CORE_ADDR pc, struct sec *section) { register struct block *b = block_for_pc_sect (pc, section); if (b == 0) return 0; return block_function (b); } /* Return the function containing pc value PC. Returns 0 if function is not known. Backward compatibility, no section */ struct symbol * find_pc_function (CORE_ADDR pc) { return find_pc_sect_function (pc, find_pc_mapped_section (pc)); } /* 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; static struct sec *cache_pc_function_section = NULL; /* Clear cache, e.g. when symbol table is discarded. */ void clear_pc_function_cache (void) { cache_pc_function_low = 0; cache_pc_function_high = 0; cache_pc_function_name = (char *) 0; cache_pc_function_section = NULL; } /* Finds the "function" (text symbol) that is smaller than PC but greatest of all of the potential text symbols in SECTION. Sets *NAME and/or *ADDRESS conditionally if that pointer is non-null. If ENDADDR is non-null, then set *ENDADDR to be the end of the function (exclusive), but passing ENDADDR as non-null means that the function might cause symbols to be read. This function either succeeds or fails (not halfway succeeds). If it succeeds, it sets *NAME, *ADDRESS, and *ENDADDR to real information and returns 1. If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and returns 0. */ int find_pc_sect_partial_function (CORE_ADDR pc, asection *section, char **name, CORE_ADDR *address, CORE_ADDR *endaddr) { struct partial_symtab *pst; struct symbol *f; struct minimal_symbol *msymbol; struct partial_symbol *psb; struct obj_section *osect; int i; CORE_ADDR mapped_pc; mapped_pc = overlay_mapped_address (pc, section); if (mapped_pc >= cache_pc_function_low && mapped_pc < cache_pc_function_high && section == cache_pc_function_section) goto return_cached_value; /* If sigtramp is in the u area, it counts as a function (especially important for step_1). */ if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc, (char *) NULL)) { cache_pc_function_low = SIGTRAMP_START (mapped_pc); cache_pc_function_high = SIGTRAMP_END (mapped_pc); cache_pc_function_name = "<sigtramp>"; cache_pc_function_section = section; goto return_cached_value; } msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section); pst = find_pc_sect_psymtab (mapped_pc, section); if (pst) { /* Need to read the symbols to get a good value for the end address. */ if (endaddr != NULL && !pst->readin) { /* Need to get the terminal in case symbol-reading produces output. */ target_terminal_ours_for_output (); PSYMTAB_TO_SYMTAB (pst); } if (pst->readin) { /* Checking whether the msymbol has a larger value is for the "pathological" case mentioned in print_frame_info. */ f = find_pc_sect_function (mapped_pc, section); if (f != NULL && (msymbol == NULL || (BLOCK_START (SYMBOL_BLOCK_VALUE (f)) >= SYMBOL_VALUE_ADDRESS (msymbol)))) { 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); cache_pc_function_section = section; goto return_cached_value; } } else { /* Now that static symbols go in the minimal symbol table, perhaps we could just ignore the partial symbols. But at least for now we use the partial or minimal symbol, whichever is larger. */ psb = find_pc_sect_psymbol (pst, mapped_pc, section); if (psb && (msymbol == NULL || (SYMBOL_VALUE_ADDRESS (psb) >= SYMBOL_VALUE_ADDRESS (msymbol)))) { /* This case isn't being cached currently. */ if (address) *address = SYMBOL_VALUE_ADDRESS (psb); if (name) *name = SYMBOL_NAME (psb); /* endaddr non-NULL can't happen here. */ return 1; } } } /* Not in the normal symbol tables, see if the pc is in a known section. If it's not, then give up. This ensures that anything beyond the end of the text seg doesn't appear to be part of the last function in the text segment. */ osect = find_pc_sect_section (mapped_pc, section); if (!osect) msymbol = NULL; /* Must be in the minimal symbol table. */ if (msymbol == NULL) { /* No available symbol. */ if (name != NULL) *name = 0; if (address != NULL) *address = 0; if (endaddr != NULL) *endaddr = 0; return 0; } cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol); cache_pc_function_name = SYMBOL_NAME (msymbol); cache_pc_function_section = section; /* Use the lesser of the next minimal symbol in the same section, or the end of the section, as the end of the function. */ /* Step over other symbols at this same address, and symbols in other sections, to find the next symbol in this section with a different address. */ for (i = 1; SYMBOL_NAME (msymbol + i) != NULL; i++) { if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol) && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol)) break; } if (SYMBOL_NAME (msymbol + i) != NULL && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr) cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i); else /* We got the start address from the last msymbol in the objfile. So the end address is the end of the section. */ cache_pc_function_high = osect->endaddr; return_cached_value: if (address) { if (pc_in_unmapped_range (pc, section)) *address = overlay_unmapped_address (cache_pc_function_low, section); else *address = cache_pc_function_low; } if (name) *name = cache_pc_function_name; if (endaddr) { if (pc_in_unmapped_range (pc, section)) { /* Because the high address is actually beyond the end of the function (and therefore possibly beyond the end of the overlay), we must actually convert (high - 1) and then add one to that. */ *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1, section); } else *endaddr = cache_pc_function_high; } return 1; } /* Backward compatibility, no section argument. */ int find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address, CORE_ADDR *endaddr) { asection *section; section = find_pc_overlay (pc); return find_pc_sect_partial_function (pc, section, name, address, endaddr); } /* Return the innermost stack frame executing inside of BLOCK, or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */ struct frame_info * block_innermost_frame (struct block *block) { struct frame_info *frame; register CORE_ADDR start; register CORE_ADDR end; CORE_ADDR calling_pc; if (block == NULL) return NULL; start = BLOCK_START (block); end = BLOCK_END (block); frame = NULL; while (1) { frame = get_prev_frame (frame); if (frame == NULL) return NULL; calling_pc = frame_address_in_block (frame); if (calling_pc >= start && calling_pc < end) return frame; } } /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK below is for infrun.c, which may give the macro a pc without that subtracted out. */ /* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and top of the stack frame which we are checking, where "bottom" and "top" refer to some section of memory which contains the code for the call dummy. Calls to this macro assume that the contents of SP_REGNUM and FP_REGNUM (or the saved values thereof), respectively, are the things to pass. This won't work on the 29k, where SP_REGNUM and FP_REGNUM don't have that meaning, but the 29k doesn't use ON_STACK. This could be fixed by generalizing this scheme, perhaps by passing in a frame and adding a few fields, at least on machines which need them for DEPRECATED_PC_IN_CALL_DUMMY. Something simpler, like checking for the stack segment, doesn't work, since various programs (threads implementations, gcc nested function stubs, etc) may either allocate stack frames in another segment, or allocate other kinds of code on the stack. */ int deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc, CORE_ADDR sp, CORE_ADDR frame_address) { return (INNER_THAN ((sp), (pc)) && (frame_address != 0) && INNER_THAN ((pc), (frame_address))); } int deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc, CORE_ADDR sp, CORE_ADDR frame_address) { return ((pc) >= CALL_DUMMY_ADDRESS () && (pc) <= (CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK)); } /* Function: frame_chain_valid Returns true for a user frame or a call_function_by_hand dummy frame, and false for the CRT0 start-up frame. Purpose is to terminate backtrace. */ int frame_chain_valid (CORE_ADDR fp, struct frame_info *fi) { /* Don't prune CALL_DUMMY frames. */ if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), 0, 0)) return 1; /* If the new frame pointer is zero, then it isn't valid. */ if (fp == 0) return 0; /* If the new frame would be inside (younger than) the previous frame, then it isn't valid. */ if (INNER_THAN (fp, get_frame_base (fi))) return 0; /* If we're already inside the entry function for the main objfile, then it isn't valid. */ if (inside_entry_func (get_frame_pc (fi))) return 0; /* If we're inside the entry file, it isn't valid. */ /* NOTE/drow 2002-12-25: should there be a way to disable this check? It assumes a single small entry file, and the way some debug readers (e.g. dbxread) figure out which object is the entry file is somewhat hokey. */ if (inside_entry_file (frame_pc_unwind (fi))) return 0; /* If the architecture has a custom FRAME_CHAIN_VALID, call it now. */ if (FRAME_CHAIN_VALID_P ()) return FRAME_CHAIN_VALID (fp, fi); return 1; }