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- /* Target-dependent code for the ALPHA architecture, for GDB, the GNU Debugger.
- Copyright 1993, 1994 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., 675 Mass Ave, Cambridge, MA 02139, USA. */
-
- #include "defs.h"
- #include "frame.h"
- #include "inferior.h"
- #include "symtab.h"
- #include "value.h"
- #include "gdbcmd.h"
- #include "gdbcore.h"
- #include "dis-asm.h"
- #include "symfile.h"
- #include "objfiles.h"
-
- /* FIXME: Some of this code should perhaps be merged with mips-tdep.c. */
-
- /* FIXME: Put this declaration in frame.h. */
- extern struct obstack frame_cache_obstack;
-
-
- /* Forward declarations. */
-
- static CORE_ADDR read_next_frame_reg PARAMS ((struct frame_info *, int));
-
- static CORE_ADDR heuristic_proc_start PARAMS ((CORE_ADDR));
-
- static alpha_extra_func_info_t heuristic_proc_desc PARAMS ((CORE_ADDR,
- CORE_ADDR,
- struct frame_info *));
-
- static alpha_extra_func_info_t find_proc_desc PARAMS ((CORE_ADDR,
- struct frame_info *));
-
- #if 0
- static int alpha_in_lenient_prologue PARAMS ((CORE_ADDR, CORE_ADDR));
- #endif
-
- static void reinit_frame_cache_sfunc PARAMS ((char *, int,
- struct cmd_list_element *));
-
- static CORE_ADDR after_prologue PARAMS ((CORE_ADDR pc,
- alpha_extra_func_info_t proc_desc));
-
- static int in_prologue PARAMS ((CORE_ADDR pc,
- alpha_extra_func_info_t proc_desc));
-
- /* Heuristic_proc_start may hunt through the text section for a long
- time across a 2400 baud serial line. Allows the user to limit this
- search. */
- static unsigned int heuristic_fence_post = 0;
-
- /* Layout of a stack frame on the alpha:
-
- | |
- pdr members: | 7th ... nth arg, |
- | `pushed' by caller. |
- | |
- ----------------|-------------------------------|<-- old_sp == vfp
- ^ ^ ^ ^ | |
- | | | | | |
- | |localoff | Copies of 1st .. 6th |
- | | | | | argument if necessary. |
- | | | v | |
- | | | --- |-------------------------------|<-- FRAME_LOCALS_ADDRESS
- | | | | |
- | | | | Locals and temporaries. |
- | | | | |
- | | | |-------------------------------|
- | | | | |
- |-fregoffset | Saved float registers. |
- | | | | F9 |
- | | | | . |
- | | | | . |
- | | | | F2 |
- | | v | |
- | | -------|-------------------------------|
- | | | |
- | | | Saved registers. |
- | | | S6 |
- |-regoffset | . |
- | | | . |
- | | | S0 |
- | | | pdr.pcreg |
- | v | |
- | ----------|-------------------------------|
- | | |
- frameoffset | Argument build area, gets |
- | | 7th ... nth arg for any |
- | | called procedure. |
- v | |
- -------------|-------------------------------|<-- sp
- | |
- */
-
- #define PROC_LOW_ADDR(proc) ((proc)->pdr.adr) /* least address */
- #define PROC_HIGH_ADDR(proc) ((proc)->pdr.iline) /* upper address bound */
- #define PROC_DUMMY_FRAME(proc) ((proc)->pdr.iopt) /* frame for CALL_DUMMY */
- #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)
- #define PROC_LOCALOFF(proc) ((proc)->pdr.localoff)
- #define PROC_SYMBOL(proc) (*(struct symbol**)&(proc)->pdr.isym)
- #define _PROC_MAGIC_ 0x0F0F0F0F
- #define PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym == _PROC_MAGIC_)
- #define SET_PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym = _PROC_MAGIC_)
-
- struct linked_proc_info
- {
- struct alpha_extra_func_info info;
- struct linked_proc_info *next;
- } *linked_proc_desc_table = NULL;
-
-
- /* Guaranteed to set fci->saved_regs to some values (it never leaves it
- NULL). */
-
- void
- alpha_find_saved_regs (frame)
- struct frame_info *frame;
- {
- int ireg;
- CORE_ADDR reg_position;
- unsigned long mask;
- alpha_extra_func_info_t proc_desc;
- int returnreg;
-
- frame->saved_regs = (struct frame_saved_regs *)
- obstack_alloc (&frame_cache_obstack, sizeof(struct frame_saved_regs));
- memset (frame->saved_regs, 0, sizeof (struct frame_saved_regs));
-
- proc_desc = frame->proc_desc;
- if (proc_desc == NULL)
- /* I'm not sure how/whether this can happen. Normally when we can't
- find a proc_desc, we "synthesize" one using heuristic_proc_desc
- and set the saved_regs right away. */
- return;
-
- /* Fill in the offsets for the registers which gen_mask says
- were saved. */
-
- reg_position = frame->frame + PROC_REG_OFFSET (proc_desc);
- mask = PROC_REG_MASK (proc_desc);
-
- returnreg = PROC_PC_REG (proc_desc);
-
- /* Note that RA is always saved first, regardless of it's actual
- register number. */
- if (mask & (1 << returnreg))
- {
- frame->saved_regs->regs[returnreg] = reg_position;
- reg_position += 8;
- mask &= ~(1 << returnreg); /* Clear bit for RA so we
- don't save again later. */
- }
-
- for (ireg = 0; ireg <= 31 ; ++ireg)
- if (mask & (1 << ireg))
- {
- frame->saved_regs->regs[ireg] = reg_position;
- reg_position += 8;
- }
-
- /* Fill in the offsets for the registers which float_mask says
- were saved. */
-
- reg_position = frame->frame + PROC_FREG_OFFSET (proc_desc);
- mask = PROC_FREG_MASK (proc_desc);
-
- for (ireg = 0; ireg <= 31 ; ++ireg)
- if (mask & (1 << ireg))
- {
- frame->saved_regs->regs[FP0_REGNUM+ireg] = reg_position;
- reg_position += 8;
- }
-
- frame->saved_regs->regs[PC_REGNUM] = frame->saved_regs->regs[returnreg];
- }
-
- static CORE_ADDR
- read_next_frame_reg(fi, regno)
- struct frame_info *fi;
- int regno;
- {
- /* If it is the frame for sigtramp we have a pointer to the sigcontext
- on the stack.
- If the stack layout for __sigtramp changes or if sigcontext offsets
- change we might have to update this code. */
- #ifndef SIGFRAME_PC_OFF
- #define SIGFRAME_PC_OFF (2 * 8)
- #define SIGFRAME_REGSAVE_OFF (4 * 8)
- #endif
- for (; fi; fi = fi->next)
- {
- if (fi->signal_handler_caller)
- {
- int offset;
- CORE_ADDR sigcontext_addr = read_memory_integer(fi->frame, 8);
-
- if (regno == PC_REGNUM)
- offset = SIGFRAME_PC_OFF;
- else if (regno < 32)
- offset = SIGFRAME_REGSAVE_OFF + regno * 8;
- else
- return 0;
- return read_memory_integer(sigcontext_addr + offset, 8);
- }
- else if (regno == SP_REGNUM)
- return fi->frame;
- else
- {
- if (fi->saved_regs == NULL)
- alpha_find_saved_regs (fi);
- if (fi->saved_regs->regs[regno])
- return read_memory_integer(fi->saved_regs->regs[regno], 8);
- }
- }
- return read_register(regno);
- }
-
- CORE_ADDR
- alpha_frame_saved_pc(frame)
- struct frame_info *frame;
- {
- alpha_extra_func_info_t proc_desc = frame->proc_desc;
- /* We have to get the saved pc from the sigcontext
- if it is a signal handler frame. */
- int pcreg = frame->signal_handler_caller ? PC_REGNUM
- : (proc_desc ? PROC_PC_REG(proc_desc) : RA_REGNUM);
-
- if (proc_desc && PROC_DESC_IS_DUMMY(proc_desc))
- return read_memory_integer(frame->frame - 8, 8);
-
- return read_next_frame_reg(frame, pcreg);
- }
-
- CORE_ADDR
- alpha_saved_pc_after_call (frame)
- struct frame_info *frame;
- {
- alpha_extra_func_info_t proc_desc = find_proc_desc (frame->pc, frame->next);
- int pcreg = proc_desc ? PROC_PC_REG (proc_desc) : RA_REGNUM;
-
- return read_register (pcreg);
- }
-
-
- static struct alpha_extra_func_info temp_proc_desc;
- static struct frame_saved_regs temp_saved_regs;
-
- /* This fencepost looks highly suspicious to me. Removing it also
- seems suspicious as it could affect remote debugging across serial
- lines. */
-
- static CORE_ADDR
- heuristic_proc_start(pc)
- CORE_ADDR pc;
- {
- CORE_ADDR start_pc = pc;
- CORE_ADDR fence = start_pc - heuristic_fence_post;
-
- if (start_pc == 0) return 0;
-
- if (heuristic_fence_post == UINT_MAX
- || fence < VM_MIN_ADDRESS)
- fence = VM_MIN_ADDRESS;
-
- /* search back for previous return */
- for (start_pc -= 4; ; start_pc -= 4)
- if (start_pc < fence)
- {
- /* It's not clear to me why we reach this point when
- stop_soon_quietly, but with this test, at least we
- don't print out warnings for every child forked (eg, on
- decstation). 22apr93 rich@cygnus.com. */
- if (!stop_soon_quietly)
- {
- static int blurb_printed = 0;
-
- if (fence == VM_MIN_ADDRESS)
- warning("Hit beginning of text section without finding");
- else
- warning("Hit heuristic-fence-post without finding");
-
- warning("enclosing function for address 0x%lx", pc);
- if (!blurb_printed)
- {
- printf_filtered ("\
- This warning occurs if you are debugging a function without any symbols\n\
- (for example, in a stripped executable). In that case, you may wish to\n\
- increase the size of the search with the `set heuristic-fence-post' command.\n\
- \n\
- Otherwise, you told GDB there was a function where there isn't one, or\n\
- (more likely) you have encountered a bug in GDB.\n");
- blurb_printed = 1;
- }
- }
-
- return 0;
- }
- else if (ABOUT_TO_RETURN(start_pc))
- break;
-
- start_pc += 4; /* skip return */
- return start_pc;
- }
-
- static alpha_extra_func_info_t
- heuristic_proc_desc(start_pc, limit_pc, next_frame)
- CORE_ADDR start_pc, limit_pc;
- struct frame_info *next_frame;
- {
- CORE_ADDR sp = read_next_frame_reg (next_frame, SP_REGNUM);
- CORE_ADDR cur_pc;
- int frame_size;
- int has_frame_reg = 0;
- unsigned long reg_mask = 0;
-
- if (start_pc == 0)
- return NULL;
- memset (&temp_proc_desc, '\0', sizeof(temp_proc_desc));
- memset (&temp_saved_regs, '\0', sizeof(struct frame_saved_regs));
- PROC_LOW_ADDR (&temp_proc_desc) = start_pc;
-
- if (start_pc + 200 < limit_pc)
- limit_pc = start_pc + 200;
- frame_size = 0;
- for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += 4)
- {
- char buf[4];
- unsigned long word;
- int status;
-
- status = read_memory_nobpt (cur_pc, buf, 4);
- if (status)
- memory_error (status, cur_pc);
- word = extract_unsigned_integer (buf, 4);
-
- if ((word & 0xffff0000) == 0x23de0000) /* lda $sp,n($sp) */
- frame_size += (-word) & 0xffff;
- else if ((word & 0xfc1f0000) == 0xb41e0000 /* stq reg,n($sp) */
- && (word & 0xffff0000) != 0xb7fe0000) /* reg != $zero */
- {
- int reg = (word & 0x03e00000) >> 21;
- reg_mask |= 1 << reg;
- temp_saved_regs.regs[reg] = sp + (short)word;
- }
- else if (word == 0x47de040f) /* bis sp,sp fp */
- has_frame_reg = 1;
- }
- if (has_frame_reg)
- PROC_FRAME_REG(&temp_proc_desc) = GCC_FP_REGNUM;
- else
- PROC_FRAME_REG(&temp_proc_desc) = SP_REGNUM;
- PROC_FRAME_OFFSET(&temp_proc_desc) = frame_size;
- PROC_REG_MASK(&temp_proc_desc) = reg_mask;
- PROC_PC_REG(&temp_proc_desc) = RA_REGNUM;
- PROC_LOCALOFF(&temp_proc_desc) = 0; /* XXX - bogus */
- return &temp_proc_desc;
- }
-
- /* This returns the PC of the first inst after the prologue. If we can't
- find the prologue, then return 0. */
-
- static CORE_ADDR
- after_prologue (pc, proc_desc)
- CORE_ADDR pc;
- alpha_extra_func_info_t proc_desc;
- {
- struct symtab_and_line sal;
- CORE_ADDR func_addr, func_end;
-
- if (!proc_desc)
- proc_desc = find_proc_desc (pc, NULL);
-
- if (proc_desc)
- {
- /* If function is frameless, then we need to do it the hard way. I
- strongly suspect that frameless always means prologueless... */
- if (PROC_FRAME_REG (proc_desc) == SP_REGNUM
- && PROC_FRAME_OFFSET (proc_desc) == 0)
- return 0;
- }
-
- if (!find_pc_partial_function (pc, NULL, &func_addr, &func_end))
- return 0; /* Unknown */
-
- sal = find_pc_line (func_addr, 0);
-
- if (sal.end < func_end)
- return sal.end;
-
- /* The line after the prologue is after the end of the function. In this
- case, tell the caller to find the prologue the hard way. */
-
- return 0;
- }
-
- /* Return non-zero if we *might* be in a function prologue. Return zero if we
- are definatly *not* in a function prologue. */
-
- static int
- in_prologue (pc, proc_desc)
- CORE_ADDR pc;
- alpha_extra_func_info_t proc_desc;
- {
- CORE_ADDR after_prologue_pc;
-
- after_prologue_pc = after_prologue (pc, proc_desc);
-
- if (after_prologue_pc == 0
- || pc < after_prologue_pc)
- return 1;
- else
- return 0;
- }
-
- static alpha_extra_func_info_t
- find_proc_desc (pc, next_frame)
- CORE_ADDR pc;
- struct frame_info *next_frame;
- {
- alpha_extra_func_info_t proc_desc;
- struct block *b;
- struct symbol *sym;
- CORE_ADDR startaddr;
-
- /* Try to get the proc_desc from the linked call dummy proc_descs
- if the pc is in the call dummy.
- This is hairy. In the case of nested dummy calls we have to find the
- right proc_desc, but we might not yet know the frame for the dummy
- as it will be contained in the proc_desc we are searching for.
- So we have to find the proc_desc whose frame is closest to the current
- stack pointer. */
-
- if (PC_IN_CALL_DUMMY (pc, 0, 0))
- {
- struct linked_proc_info *link;
- CORE_ADDR sp = read_next_frame_reg (next_frame, SP_REGNUM);
- alpha_extra_func_info_t found_proc_desc = NULL;
- long min_distance = LONG_MAX;
-
- for (link = linked_proc_desc_table; link; link = link->next)
- {
- long distance = (CORE_ADDR) PROC_DUMMY_FRAME (&link->info) - sp;
- if (distance > 0 && distance < min_distance)
- {
- min_distance = distance;
- found_proc_desc = &link->info;
- }
- }
- if (found_proc_desc != NULL)
- return found_proc_desc;
- }
-
- b = block_for_pc(pc);
-
- find_pc_partial_function (pc, NULL, &startaddr, NULL);
- if (b == NULL)
- sym = NULL;
- else
- {
- 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. */
- sym = NULL;
- else
- sym = lookup_symbol (MIPS_EFI_SYMBOL_NAME, b, LABEL_NAMESPACE,
- 0, NULL);
- }
-
- if (sym)
- {
- /* IF this is the topmost frame AND
- * (this proc does not have debugging information OR
- * the PC is in the procedure prologue)
- * THEN create a "heuristic" proc_desc (by analyzing
- * the actual code) to replace the "official" proc_desc.
- */
- proc_desc = (alpha_extra_func_info_t)SYMBOL_VALUE(sym);
- if (next_frame == NULL)
- {
- if (PROC_DESC_IS_DUMMY (proc_desc) || in_prologue (pc, proc_desc))
- {
- alpha_extra_func_info_t found_heuristic =
- heuristic_proc_desc (PROC_LOW_ADDR (proc_desc),
- pc, next_frame);
- PROC_LOCALOFF (found_heuristic) = PROC_LOCALOFF (proc_desc);
- if (found_heuristic)
- proc_desc = found_heuristic;
- }
- }
- }
- else
- {
- /* Is linked_proc_desc_table really necessary? It only seems to be used
- by procedure call dummys. However, the procedures being called ought
- to have their own proc_descs, and even if they don't,
- heuristic_proc_desc knows how to create them! */
-
- register struct linked_proc_info *link;
- for (link = linked_proc_desc_table; link; link = link->next)
- if (PROC_LOW_ADDR(&link->info) <= pc
- && PROC_HIGH_ADDR(&link->info) > pc)
- return &link->info;
-
- if (startaddr == 0)
- startaddr = heuristic_proc_start (pc);
-
- proc_desc =
- heuristic_proc_desc (startaddr, pc, next_frame);
- }
- return proc_desc;
- }
-
- alpha_extra_func_info_t cached_proc_desc;
-
- CORE_ADDR
- alpha_frame_chain(frame)
- struct frame_info *frame;
- {
- alpha_extra_func_info_t proc_desc;
- CORE_ADDR saved_pc = FRAME_SAVED_PC(frame);
-
- if (saved_pc == 0 || inside_entry_file (saved_pc))
- return 0;
-
- proc_desc = find_proc_desc(saved_pc, frame);
- if (!proc_desc)
- return 0;
-
- cached_proc_desc = proc_desc;
-
- /* Fetch the frame pointer for a dummy frame from the procedure
- descriptor. */
- if (PROC_DESC_IS_DUMMY(proc_desc))
- return (CORE_ADDR) PROC_DUMMY_FRAME(proc_desc);
-
- /* If no frame pointer and frame size is zero, we must be at end
- of stack (or otherwise hosed). If we don't check frame size,
- we loop forever if we see a zero size frame. */
- if (PROC_FRAME_REG (proc_desc) == SP_REGNUM
- && PROC_FRAME_OFFSET (proc_desc) == 0
- /* The previous frame from a sigtramp frame might be frameless
- and have frame size zero. */
- && !frame->signal_handler_caller)
- {
- /* The alpha __sigtramp routine is frameless and has a frame size
- of zero, but we are able to backtrace through it. */
- char *name;
- find_pc_partial_function (saved_pc, &name,
- (CORE_ADDR *)NULL, (CORE_ADDR *)NULL);
- if (IN_SIGTRAMP (saved_pc, name))
- return frame->frame;
- else
- return 0;
- }
- else
- return read_next_frame_reg(frame, PROC_FRAME_REG(proc_desc))
- + PROC_FRAME_OFFSET(proc_desc);
- }
-
- void
- init_extra_frame_info (frame)
- struct frame_info *frame;
- {
- /* Use proc_desc calculated in frame_chain */
- alpha_extra_func_info_t proc_desc =
- frame->next ? cached_proc_desc : find_proc_desc(frame->pc, frame->next);
-
- frame->saved_regs = NULL;
- frame->proc_desc =
- proc_desc == &temp_proc_desc ? 0 : proc_desc;
- if (proc_desc)
- {
- /* Get the locals offset from the procedure descriptor, it is valid
- even if we are in the middle of the prologue. */
- frame->localoff = PROC_LOCALOFF(proc_desc);
-
- /* Fixup frame-pointer - only needed for top frame */
-
- /* Fetch the frame pointer for a dummy frame from the procedure
- descriptor. */
- if (PROC_DESC_IS_DUMMY(proc_desc))
- frame->frame = (CORE_ADDR) PROC_DUMMY_FRAME(proc_desc);
-
- /* This may not be quite right, if proc has a real frame register.
- Get the value of the frame relative sp, procedure might have been
- interrupted by a signal at it's very start. */
- else if (frame->pc == PROC_LOW_ADDR (proc_desc) && !PROC_DESC_IS_DUMMY (proc_desc))
- frame->frame = read_next_frame_reg (frame->next, SP_REGNUM);
- else
- frame->frame = read_next_frame_reg (frame->next, PROC_FRAME_REG (proc_desc))
- + PROC_FRAME_OFFSET (proc_desc);
-
- if (proc_desc == &temp_proc_desc)
- {
- frame->saved_regs = (struct frame_saved_regs*)
- obstack_alloc (&frame_cache_obstack,
- sizeof (struct frame_saved_regs));
- *frame->saved_regs = temp_saved_regs;
- frame->saved_regs->regs[PC_REGNUM] = frame->saved_regs->regs[RA_REGNUM];
- }
- }
- }
-
- /* ALPHA stack frames are almost impenetrable. When execution stops,
- we basically have to look at symbol information for the function
- that we stopped in, which tells us *which* register (if any) is
- the base of the frame pointer, and what offset from that register
- the frame itself is at.
-
- This presents a problem when trying to examine a stack in memory
- (that isn't executing at the moment), using the "frame" command. We
- don't have a PC, nor do we have any registers except SP.
-
- This routine takes two arguments, SP and PC, and tries to make the
- cached frames look as if these two arguments defined a frame on the
- cache. This allows the rest of info frame to extract the important
- arguments without difficulty. */
-
- struct frame_info *
- setup_arbitrary_frame (argc, argv)
- int argc;
- CORE_ADDR *argv;
- {
- if (argc != 2)
- error ("ALPHA frame specifications require two arguments: sp and pc");
-
- return create_new_frame (argv[0], argv[1]);
- }
-
- /* The alpha passes the first six arguments in the registers, the rest on
- the stack. The register arguments are eventually transferred to the
- argument transfer area immediately below the stack by the called function
- anyway. So we `push' at least six arguments on the stack, `reload' the
- argument registers and then adjust the stack pointer to point past the
- sixth argument. This algorithm simplifies the passing of a large struct
- which extends from the registers to the stack.
- If the called function is returning a structure, the address of the
- structure to be returned is passed as a hidden first argument. */
-
- CORE_ADDR
- alpha_push_arguments (nargs, args, sp, struct_return, struct_addr)
- int nargs;
- value_ptr *args;
- CORE_ADDR sp;
- int struct_return;
- CORE_ADDR struct_addr;
- {
- register i;
- int accumulate_size = struct_return ? 8 : 0;
- int arg_regs_size = ALPHA_NUM_ARG_REGS * 8;
- struct alpha_arg { char *contents; int len; int offset; };
- struct alpha_arg *alpha_args =
- (struct alpha_arg*)alloca (nargs * sizeof (struct alpha_arg));
- register struct alpha_arg *m_arg;
- char raw_buffer[sizeof (CORE_ADDR)];
- int required_arg_regs;
-
- for (i = 0, m_arg = alpha_args; i < nargs; i++, m_arg++)
- {
- value_ptr arg = value_arg_coerce (args[i]);
- /* Cast argument to long if necessary as the compiler does it too. */
- if (TYPE_LENGTH (VALUE_TYPE (arg)) < TYPE_LENGTH (builtin_type_long))
- arg = value_cast (builtin_type_long, arg);
- m_arg->len = TYPE_LENGTH (VALUE_TYPE (arg));
- m_arg->offset = accumulate_size;
- accumulate_size = (accumulate_size + m_arg->len + 7) & ~7;
- m_arg->contents = VALUE_CONTENTS(arg);
- }
-
- /* Determine required argument register loads, loading an argument register
- is expensive as it uses three ptrace calls. */
- required_arg_regs = accumulate_size / 8;
- if (required_arg_regs > ALPHA_NUM_ARG_REGS)
- required_arg_regs = ALPHA_NUM_ARG_REGS;
-
- /* Make room for the arguments on the stack. */
- if (accumulate_size < arg_regs_size)
- accumulate_size = arg_regs_size;
- sp -= accumulate_size;
-
- /* Keep sp aligned to a multiple of 16 as the compiler does it too. */
- sp &= ~15;
-
- /* `Push' arguments on the stack. */
- for (i = nargs; m_arg--, --i >= 0; )
- write_memory(sp + m_arg->offset, m_arg->contents, m_arg->len);
- if (struct_return)
- {
- store_address (raw_buffer, sizeof (CORE_ADDR), struct_addr);
- write_memory (sp, raw_buffer, sizeof (CORE_ADDR));
- }
-
- /* Load the argument registers. */
- for (i = 0; i < required_arg_regs; i++)
- {
- LONGEST val;
-
- val = read_memory_integer (sp + i * 8, 8);
- write_register (A0_REGNUM + i, val);
- write_register (FPA0_REGNUM + i, val);
- }
-
- return sp + arg_regs_size;
- }
-
- void
- alpha_push_dummy_frame()
- {
- int ireg;
- struct linked_proc_info *link;
- alpha_extra_func_info_t proc_desc;
- CORE_ADDR sp = read_register (SP_REGNUM);
- CORE_ADDR save_address;
- char raw_buffer[MAX_REGISTER_RAW_SIZE];
- unsigned long mask;
-
- link = (struct linked_proc_info *) xmalloc(sizeof (struct linked_proc_info));
- link->next = linked_proc_desc_table;
- linked_proc_desc_table = link;
-
- proc_desc = &link->info;
-
- /*
- * The registers we must save are all those not preserved across
- * procedure calls.
- * In addition, we must save the PC and RA.
- *
- * Dummy frame layout:
- * (high memory)
- * Saved PC
- * Saved F30
- * ...
- * Saved F0
- * Saved R29
- * ...
- * Saved R0
- * Saved R26 (RA)
- * Parameter build area
- * (low memory)
- */
-
- /* MASK(i,j) == (1<<i) + (1<<(i+1)) + ... + (1<<j)). Assume i<=j<31. */
- #define MASK(i,j) (((1L << ((j)+1)) - 1) ^ ((1L << (i)) - 1))
- #define GEN_REG_SAVE_MASK (MASK(0,8) | MASK(16,29))
- #define GEN_REG_SAVE_COUNT 24
- #define FLOAT_REG_SAVE_MASK (MASK(0,1) | MASK(10,30))
- #define FLOAT_REG_SAVE_COUNT 23
- /* The special register is the PC as we have no bit for it in the save masks.
- alpha_frame_saved_pc knows where the pc is saved in a dummy frame. */
- #define SPECIAL_REG_SAVE_COUNT 1
-
- PROC_REG_MASK(proc_desc) = GEN_REG_SAVE_MASK;
- PROC_FREG_MASK(proc_desc) = FLOAT_REG_SAVE_MASK;
- /* PROC_REG_OFFSET is the offset from the dummy frame to the saved RA,
- but keep SP aligned to a multiple of 16. */
- PROC_REG_OFFSET(proc_desc) =
- - ((8 * (SPECIAL_REG_SAVE_COUNT
- + GEN_REG_SAVE_COUNT
- + FLOAT_REG_SAVE_COUNT)
- + 15) & ~15);
- PROC_FREG_OFFSET(proc_desc) =
- PROC_REG_OFFSET(proc_desc) + 8 * GEN_REG_SAVE_COUNT;
-
- /* Save general registers.
- The return address register is the first saved register, all other
- registers follow in ascending order.
- The PC is saved immediately below the SP. */
- save_address = sp + PROC_REG_OFFSET(proc_desc);
- store_address (raw_buffer, 8, read_register (RA_REGNUM));
- write_memory (save_address, raw_buffer, 8);
- save_address += 8;
- mask = PROC_REG_MASK(proc_desc) & 0xffffffffL;
- for (ireg = 0; mask; ireg++, mask >>= 1)
- if (mask & 1)
- {
- if (ireg == RA_REGNUM)
- continue;
- store_address (raw_buffer, 8, read_register (ireg));
- write_memory (save_address, raw_buffer, 8);
- save_address += 8;
- }
-
- store_address (raw_buffer, 8, read_register (PC_REGNUM));
- write_memory (sp - 8, raw_buffer, 8);
-
- /* Save floating point registers. */
- save_address = sp + PROC_FREG_OFFSET(proc_desc);
- mask = PROC_FREG_MASK(proc_desc) & 0xffffffffL;
- for (ireg = 0; mask; ireg++, mask >>= 1)
- if (mask & 1)
- {
- store_address (raw_buffer, 8, read_register (ireg + FP0_REGNUM));
- write_memory (save_address, raw_buffer, 8);
- save_address += 8;
- }
-
- /* Set and save the frame address for the dummy.
- This is tricky. The only registers that are suitable for a frame save
- are those that are preserved across procedure calls (s0-s6). But if
- a read system call is interrupted and then a dummy call is made
- (see testsuite/gdb.t17/interrupt.exp) the dummy call hangs till the read
- is satisfied. Then it returns with the s0-s6 registers set to the values
- on entry to the read system call and our dummy frame pointer would be
- destroyed. So we save the dummy frame in the proc_desc and handle the
- retrieval of the frame pointer of a dummy specifically. The frame register
- is set to the virtual frame (pseudo) register, it's value will always
- be read as zero and will help us to catch any errors in the dummy frame
- retrieval code. */
- PROC_DUMMY_FRAME(proc_desc) = sp;
- PROC_FRAME_REG(proc_desc) = FP_REGNUM;
- PROC_FRAME_OFFSET(proc_desc) = 0;
- sp += PROC_REG_OFFSET(proc_desc);
- write_register (SP_REGNUM, sp);
-
- PROC_LOW_ADDR(proc_desc) = CALL_DUMMY_ADDRESS ();
- PROC_HIGH_ADDR(proc_desc) = PROC_LOW_ADDR(proc_desc) + 4;
-
- SET_PROC_DESC_IS_DUMMY(proc_desc);
- PROC_PC_REG(proc_desc) = RA_REGNUM;
- }
-
- void
- alpha_pop_frame()
- {
- register int regnum;
- struct frame_info *frame = get_current_frame ();
- CORE_ADDR new_sp = frame->frame;
-
- alpha_extra_func_info_t proc_desc = frame->proc_desc;
-
- write_register (PC_REGNUM, FRAME_SAVED_PC(frame));
- if (frame->saved_regs == NULL)
- alpha_find_saved_regs (frame);
- if (proc_desc)
- {
- for (regnum = 32; --regnum >= 0; )
- if (PROC_REG_MASK(proc_desc) & (1 << regnum))
- write_register (regnum,
- read_memory_integer (frame->saved_regs->regs[regnum],
- 8));
- for (regnum = 32; --regnum >= 0; )
- if (PROC_FREG_MASK(proc_desc) & (1 << regnum))
- write_register (regnum + FP0_REGNUM,
- read_memory_integer (frame->saved_regs->regs[regnum + FP0_REGNUM], 8));
- }
- write_register (SP_REGNUM, new_sp);
- flush_cached_frames ();
-
- if (proc_desc && PROC_DESC_IS_DUMMY(proc_desc))
- {
- struct linked_proc_info *pi_ptr, *prev_ptr;
-
- for (pi_ptr = linked_proc_desc_table, prev_ptr = NULL;
- pi_ptr != NULL;
- prev_ptr = pi_ptr, pi_ptr = pi_ptr->next)
- {
- if (&pi_ptr->info == proc_desc)
- break;
- }
-
- if (pi_ptr == NULL)
- error ("Can't locate dummy extra frame info\n");
-
- if (prev_ptr != NULL)
- prev_ptr->next = pi_ptr->next;
- else
- linked_proc_desc_table = pi_ptr->next;
-
- free (pi_ptr);
- }
- }
-
- /* To skip prologues, I use this predicate. Returns either PC itself
- if the code at PC does not look like a function prologue; otherwise
- returns an address that (if we're lucky) follows the prologue. If
- LENIENT, then we must skip everything which is involved in setting
- up the frame (it's OK to skip more, just so long as we don't skip
- anything which might clobber the registers which are being saved.
- Currently we must not skip more on the alpha, but we might the lenient
- stuff some day. */
-
- CORE_ADDR
- alpha_skip_prologue (pc, lenient)
- CORE_ADDR pc;
- int lenient;
- {
- unsigned long inst;
- int offset;
- CORE_ADDR post_prologue_pc;
- char buf[4];
-
- #ifdef GDB_TARGET_HAS_SHARED_LIBS
- /* Silently return the unaltered pc upon memory errors.
- This could happen on OSF/1 if decode_line_1 tries to skip the
- prologue for quickstarted shared library functions when the
- shared library is not yet mapped in.
- Reading target memory is slow over serial lines, so we perform
- this check only if the target has shared libraries. */
- if (target_read_memory (pc, buf, 4))
- return pc;
- #endif
-
- /* See if we can determine the end of the prologue via the symbol table.
- If so, then return either PC, or the PC after the prologue, whichever
- is greater. */
-
- post_prologue_pc = after_prologue (pc, NULL);
-
- if (post_prologue_pc != 0)
- return max (pc, post_prologue_pc);
-
- /* Can't determine prologue from the symbol table, need to examine
- instructions. */
-
- /* Skip the typical prologue instructions. These are the stack adjustment
- instruction and the instructions that save registers on the stack
- or in the gcc frame. */
- for (offset = 0; offset < 100; offset += 4)
- {
- int status;
-
- status = read_memory_nobpt (pc + offset, buf, 4);
- if (status)
- memory_error (status, pc + offset);
- inst = extract_unsigned_integer (buf, 4);
-
- /* The alpha has no delay slots. But let's keep the lenient stuff,
- we might need it for something else in the future. */
- if (lenient && 0)
- continue;
-
- if ((inst & 0xffff0000) == 0x27bb0000) /* ldah $gp,n($t12) */
- continue;
- if ((inst & 0xffff0000) == 0x23bd0000) /* lda $gp,n($gp) */
- continue;
- if ((inst & 0xffff0000) == 0x23de0000) /* lda $sp,n($sp) */
- continue;
- else if ((inst & 0xfc1f0000) == 0xb41e0000
- && (inst & 0xffff0000) != 0xb7fe0000)
- continue; /* stq reg,n($sp) */
- /* reg != $zero */
- else if ((inst & 0xfc1f0000) == 0x9c1e0000
- && (inst & 0xffff0000) != 0x9ffe0000)
- continue; /* stt reg,n($sp) */
- /* reg != $zero */
- else if (inst == 0x47de040f) /* bis sp,sp,fp */
- continue;
- else
- break;
- }
- return pc + offset;
- }
-
- #if 0
- /* Is address PC in the prologue (loosely defined) for function at
- STARTADDR? */
-
- static int
- alpha_in_lenient_prologue (startaddr, pc)
- CORE_ADDR startaddr;
- CORE_ADDR pc;
- {
- CORE_ADDR end_prologue = alpha_skip_prologue (startaddr, 1);
- return pc >= startaddr && pc < end_prologue;
- }
- #endif
-
- /* The alpha needs a conversion between register and memory format if
- the register is a floating point register and
- memory format is float, as the register format must be double
- or
- memory format is an integer with 4 bytes or less, as the representation
- of integers in floating point registers is different. */
- void
- alpha_register_convert_to_virtual (regnum, valtype, raw_buffer, virtual_buffer)
- int regnum;
- struct type *valtype;
- char *raw_buffer;
- char *virtual_buffer;
- {
- if (TYPE_LENGTH (valtype) >= REGISTER_RAW_SIZE (regnum))
- {
- memcpy (virtual_buffer, raw_buffer, REGISTER_VIRTUAL_SIZE (regnum));
- return;
- }
-
- if (TYPE_CODE (valtype) == TYPE_CODE_FLT)
- {
- double d = extract_floating (raw_buffer, REGISTER_RAW_SIZE (regnum));
- store_floating (virtual_buffer, TYPE_LENGTH (valtype), d);
- }
- else if (TYPE_CODE (valtype) == TYPE_CODE_INT && TYPE_LENGTH (valtype) <= 4)
- {
- unsigned LONGEST l;
- l = extract_unsigned_integer (raw_buffer, REGISTER_RAW_SIZE (regnum));
- l = ((l >> 32) & 0xc0000000) | ((l >> 29) & 0x3fffffff);
- store_unsigned_integer (virtual_buffer, TYPE_LENGTH (valtype), l);
- }
- else
- error ("Cannot retrieve value from floating point register");
- }
-
- void
- alpha_register_convert_to_raw (valtype, regnum, virtual_buffer, raw_buffer)
- struct type *valtype;
- int regnum;
- char *virtual_buffer;
- char *raw_buffer;
- {
- if (TYPE_LENGTH (valtype) >= REGISTER_RAW_SIZE (regnum))
- {
- memcpy (raw_buffer, virtual_buffer, REGISTER_RAW_SIZE (regnum));
- return;
- }
-
- if (TYPE_CODE (valtype) == TYPE_CODE_FLT)
- {
- double d = extract_floating (virtual_buffer, TYPE_LENGTH (valtype));
- store_floating (raw_buffer, REGISTER_RAW_SIZE (regnum), d);
- }
- else if (TYPE_CODE (valtype) == TYPE_CODE_INT && TYPE_LENGTH (valtype) <= 4)
- {
- unsigned LONGEST l;
- if (TYPE_UNSIGNED (valtype))
- l = extract_unsigned_integer (virtual_buffer, TYPE_LENGTH (valtype));
- else
- l = extract_signed_integer (virtual_buffer, TYPE_LENGTH (valtype));
- l = ((l & 0xc0000000) << 32) | ((l & 0x3fffffff) << 29);
- store_unsigned_integer (raw_buffer, REGISTER_RAW_SIZE (regnum), l);
- }
- else
- error ("Cannot store value in floating point register");
- }
-
- /* Given a return value in `regbuf' with a type `valtype',
- extract and copy its value into `valbuf'. */
-
- void
- alpha_extract_return_value (valtype, regbuf, valbuf)
- struct type *valtype;
- char regbuf[REGISTER_BYTES];
- char *valbuf;
- {
- int regnum;
-
- regnum = TYPE_CODE (valtype) == TYPE_CODE_FLT ? FP0_REGNUM : V0_REGNUM;
-
- memcpy (valbuf, regbuf + REGISTER_BYTE (regnum), TYPE_LENGTH (valtype));
- }
-
- /* Given a return value in `regbuf' with a type `valtype',
- write its value into the appropriate register. */
-
- void
- alpha_store_return_value (valtype, valbuf)
- struct type *valtype;
- char *valbuf;
- {
- int regnum;
- char raw_buffer[MAX_REGISTER_RAW_SIZE];
-
- regnum = TYPE_CODE (valtype) == TYPE_CODE_FLT ? FP0_REGNUM : V0_REGNUM;
- memcpy(raw_buffer, valbuf, TYPE_LENGTH (valtype));
-
- write_register_bytes(REGISTER_BYTE (regnum), raw_buffer, TYPE_LENGTH (valtype));
- }
-
- /* Just like reinit_frame_cache, but with the right arguments to be
- callable as an sfunc. */
-
- static void
- reinit_frame_cache_sfunc (args, from_tty, c)
- char *args;
- int from_tty;
- struct cmd_list_element *c;
- {
- reinit_frame_cache ();
- }
-
- /* This is the definition of CALL_DUMMY_ADDRESS. It's a heuristic that is used
- to find a convenient place in the text segment to stick a breakpoint to
- detect the completion of a target function call (ala call_function_by_hand).
- */
-
- CORE_ADDR
- alpha_call_dummy_address ()
- {
- CORE_ADDR entry;
- struct minimal_symbol *sym;
-
- entry = entry_point_address ();
-
- if (entry != 0)
- return entry;
-
- sym = lookup_minimal_symbol ("_Prelude", NULL, symfile_objfile);
-
- if (!sym || MSYMBOL_TYPE (sym) != mst_text)
- return 0;
- else
- return SYMBOL_VALUE_ADDRESS (sym) + 4;
- }
-
- void
- _initialize_alpha_tdep ()
- {
- struct cmd_list_element *c;
-
- tm_print_insn = print_insn_alpha;
-
- /* Let the user set the fence post for heuristic_proc_start. */
-
- /* We really would like to have both "0" and "unlimited" work, but
- command.c doesn't deal with that. So make it a var_zinteger
- because the user can always use "999999" or some such for unlimited. */
- c = add_set_cmd ("heuristic-fence-post", class_support, var_zinteger,
- (char *) &heuristic_fence_post,
- "\
- Set the distance searched for the start of a function.\n\
- If you are debugging a stripped executable, GDB needs to search through the\n\
- program for the start of a function. This command sets the distance of the\n\
- search. The only need to set it is when debugging a stripped executable.",
- &setlist);
- /* We need to throw away the frame cache when we set this, since it
- might change our ability to get backtraces. */
- c->function.sfunc = reinit_frame_cache_sfunc;
- add_show_from_set (c, &showlist);
- }
-