From ba944fbb321cf4fac89b7b58de118865680616c4 Mon Sep 17 00:00:00 2001 From: Andrew Cagney Date: Sat, 1 Jun 2002 20:44:21 +0000 Subject: * stack.c (frame_info): Use frame_register_unwind instead of saved_regs. Mention when the SP is on the stack or in a register. * frame.h (frame_register_unwind_ftype): Define. Document. (struct frame_info): Add field register_unwind and register_unwind_cache. (frame_register_unwind): Declare. (generic_unwind_get_saved_register): Declare. * frame.c (frame_register_unwind): New function. (generic_unwind_get_saved_register): New function. * blockframe.c (generic_call_dummy_register_unwind): New function. (frame_saved_regs_register_unwind): New function. (set_unwind_by_pc): New function. (create_new_frame): New function. (get_prev_frame): New function. --- gdb/blockframe.c | 184 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 184 insertions(+) (limited to 'gdb/blockframe.c') diff --git a/gdb/blockframe.c b/gdb/blockframe.c index 706d0283cf1..deeda4c7df6 100644 --- a/gdb/blockframe.c +++ b/gdb/blockframe.c @@ -34,9 +34,28 @@ #include "inferior.h" /* for read_pc */ #include "annotate.h" #include "regcache.h" +#include "gdb_assert.h" /* Prototypes for exported functions. */ +static void generic_call_dummy_register_unwind (struct frame_info *frame, + void **cache, + int regnum, + int *optimized, + enum lval_type *lval, + CORE_ADDR *addrp, + int *realnum, + void *raw_buffer); +static void frame_saved_regs_register_unwind (struct frame_info *frame, + void **cache, + int regnum, + int *optimized, + enum lval_type *lval, + CORE_ADDR *addrp, + int *realnum, + void *buffer); + + void _initialize_blockframe (void); /* A default FRAME_CHAIN_VALID, in the form that is suitable for most @@ -208,6 +227,27 @@ set_current_frame (struct frame_info *frame) current_frame = frame; } + +/* Using the PC, select a mechanism for unwinding a frame returning + the previous frame. The register unwind function should, on + demand, initialize the ->context object. */ + +static void +set_unwind_by_pc (CORE_ADDR pc, CORE_ADDR fp, + frame_register_unwind_ftype **unwind) +{ + if (!USE_GENERIC_DUMMY_FRAMES) + /* Still need to set this to something. The ``info frame'' code + calls this function to find out where the saved registers are. + Hopefully this is robust enough to stop any core dumps and + return vaguely correct values.. */ + *unwind = frame_saved_regs_register_unwind; + else if (PC_IN_CALL_DUMMY (pc, fp, fp)) + *unwind = generic_call_dummy_register_unwind; + else + *unwind = frame_saved_regs_register_unwind; +} + /* Create an arbitrary (i.e. address specified by user) or innermost frame. Always returns a non-NULL value. */ @@ -232,6 +272,9 @@ create_new_frame (CORE_ADDR addr, CORE_ADDR pc) if (INIT_EXTRA_FRAME_INFO_P ()) INIT_EXTRA_FRAME_INFO (0, fi); + /* Select/initialize an unwind function. */ + set_unwind_by_pc (fi->pc, fi->frame, &fi->register_unwind); + return fi; } @@ -456,6 +499,12 @@ get_prev_frame (struct frame_info *next_frame) } } + /* Initialize the code used to unwind the frame PREV based on the PC + (and probably other architectural information). The PC lets you + check things like the debug info at that point (dwarf2cfi?) and + use that to decide how the frame should be unwound. */ + set_unwind_by_pc (prev->pc, prev->frame, &prev->register_unwind); + find_pc_partial_function (prev->pc, &name, (CORE_ADDR *) NULL, (CORE_ADDR *) NULL); if (PC_IN_SIGTRAMP (prev->pc, name)) @@ -1269,6 +1318,141 @@ generic_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun, int nargs, return; } +/* Given a call-dummy dummy-frame, return the registers. Here the + register value is taken from the local copy of the register buffer. */ + +static void +generic_call_dummy_register_unwind (struct frame_info *frame, void **cache, + int regnum, int *optimized, + enum lval_type *lvalp, CORE_ADDR *addrp, + int *realnum, void *bufferp) +{ + gdb_assert (frame != NULL); + gdb_assert (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame)); + + /* Describe the register's location. Generic dummy frames always + have the register value in an ``expression''. */ + *optimized = 0; + *lvalp = not_lval; + *addrp = 0; + *realnum = -1; + + /* If needed, find and return the value of the register. */ + if (bufferp != NULL) + { + char *registers; +#if 1 + /* Get the address of the register buffer that contains all the + saved registers for this dummy frame. Cache that address. */ + registers = (*cache); + if (registers == NULL) + { + registers = generic_find_dummy_frame (frame->pc, frame->frame); + (*cache) = registers; + } +#else + /* Get the address of the register buffer that contains the + saved registers and then extract the value from that. */ + registers = generic_find_dummy_frame (frame->pc, frame->frame); +#endif + gdb_assert (registers != NULL); + /* Return the actual value. */ + memcpy (bufferp, registers + REGISTER_BYTE (regnum), + REGISTER_RAW_SIZE (regnum)); + } +} + +/* Return the register saved in the simplistic ``saved_regs'' cache. + If the value isn't here AND a value is needed, try the next inner + most frame. */ + +static void +frame_saved_regs_register_unwind (struct frame_info *frame, void **cache, + int regnum, int *optimizedp, + enum lval_type *lvalp, CORE_ADDR *addrp, + int *realnump, void *bufferp) +{ + /* There is always a frame at this point. And THIS is the frame + we're interested in. */ + gdb_assert (frame != NULL); + gdb_assert (!PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame)); + + /* Load the saved_regs register cache. */ + if (frame->saved_regs == NULL) + FRAME_INIT_SAVED_REGS (frame); + + if (frame->saved_regs != NULL + && frame->saved_regs[regnum] != 0) + { + if (regnum == SP_REGNUM) + { + /* SP register treated specially. */ + *optimizedp = 0; + *lvalp = not_lval; + *addrp = 0; + *realnump = -1; + if (bufferp != NULL) + store_address (bufferp, REGISTER_RAW_SIZE (regnum), + frame->saved_regs[regnum]); + } + else + { + /* Any other register is saved in memory, fetch it but cache + a local copy of its value. */ + *optimizedp = 0; + *lvalp = lval_memory; + *addrp = frame->saved_regs[regnum]; + *realnump = -1; + if (bufferp != NULL) + { +#if 1 + /* Save each register value, as it is read in, in a + frame based cache. */ + void **regs = (*cache); + if (regs == NULL) + { + int sizeof_cache = ((NUM_REGS + NUM_PSEUDO_REGS) + * sizeof (void *)); + regs = frame_obstack_alloc (sizeof_cache); + memset (regs, 0, sizeof_cache); + (*cache) = regs; + } + if (regs[regnum] == NULL) + { + regs[regnum] + = frame_obstack_alloc (REGISTER_RAW_SIZE (regnum)); + read_memory (frame->saved_regs[regnum], regs[regnum], + REGISTER_RAW_SIZE (regnum)); + } + memcpy (bufferp, regs[regnum], REGISTER_RAW_SIZE (regnum)); +#else + /* Read the value in from memory. */ + read_memory (frame->saved_regs[regnum], bufferp, + REGISTER_RAW_SIZE (regnum)); +#endif + } + } + return; + } + + /* No luck, assume this and the next frame have the same register + value. If a value is needed, pass the request on down the chain; + otherwise just return an indication that the value is in the same + register as the next frame. */ + if (bufferp == NULL) + { + *optimizedp = 0; + *lvalp = lval_register; + *addrp = 0; + *realnump = regnum; + } + else + { + frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp, + realnump, bufferp); + } +} + /* Function: get_saved_register Find register number REGNUM relative to FRAME and put its (raw, target format) contents in *RAW_BUFFER. -- cgit v1.2.1