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Diffstat (limited to 'gdb/alpha-tdep.c')
| -rw-r--r-- | gdb/alpha-tdep.c | 1410 |
1 files changed, 1410 insertions, 0 deletions
diff --git a/gdb/alpha-tdep.c b/gdb/alpha-tdep.c new file mode 100644 index 00000000000..02010160b96 --- /dev/null +++ b/gdb/alpha-tdep.c @@ -0,0 +1,1410 @@ +/* Target-dependent code for the ALPHA architecture, for GDB, the GNU Debugger. + Copyright 1993, 94, 95, 96, 97, 1998 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 "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" +#include "gdb_string.h" + +/* FIXME: Some of this code should perhaps be merged with mips-tdep.c. */ + +/* Prototypes for local functions. */ + +static alpha_extra_func_info_t push_sigtramp_desc PARAMS ((CORE_ADDR low_addr)); + +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 alpha_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; + + +/* Under GNU/Linux, signal handler invocations can be identified by the + designated code sequence that is used to return from a signal + handler. In particular, the return address of a signal handler + points to the following sequence (the first instruction is quadword + aligned): + + bis $30,$30,$16 + addq $31,0x67,$0 + call_pal callsys + + Each instruction has a unique encoding, so we simply attempt to + match the instruction the pc is pointing to with any of the above + instructions. If there is a hit, we know the offset to the start + of the designated sequence and can then check whether we really are + executing in a designated sequence. If not, -1 is returned, + otherwise the offset from the start of the desingated sequence is + returned. + + There is a slight chance of false hits: code could jump into the + middle of the designated sequence, in which case there is no + guarantee that we are in the middle of a sigreturn syscall. Don't + think this will be a problem in praxis, though. +*/ + +long +alpha_linux_sigtramp_offset (CORE_ADDR pc) +{ + unsigned int i[3], w; + long off; + + if (read_memory_nobpt(pc, (char *) &w, 4) != 0) + return -1; + + off = -1; + switch (w) + { + case 0x47de0410: off = 0; break; /* bis $30,$30,$16 */ + case 0x43ecf400: off = 4; break; /* addq $31,0x67,$0 */ + case 0x00000083: off = 8; break; /* call_pal callsys */ + default: return -1; + } + pc -= off; + if (pc & 0x7) + { + /* designated sequence is not quadword aligned */ + return -1; + } + + if (read_memory_nobpt(pc, (char *) i, sizeof(i)) != 0) + return -1; + + if (i[0] == 0x47de0410 && i[1] == 0x43ecf400 && i[2] == 0x00000083) + return off; + + return -1; +} + + +/* Under OSF/1, the __sigtramp routine is frameless and has a frame + size of zero, but we are able to backtrace through it. */ +CORE_ADDR +alpha_osf_skip_sigtramp_frame (frame, pc) + struct frame_info *frame; + CORE_ADDR pc; +{ + char *name; + find_pc_partial_function (pc, &name, (CORE_ADDR *)NULL, (CORE_ADDR *)NULL); + if (IN_SIGTRAMP (pc, name)) + return frame->frame; + else + return 0; +} + + +/* Dynamically create a signal-handler caller procedure descriptor for + the signal-handler return code starting at address LOW_ADDR. The + descriptor is added to the linked_proc_desc_table. */ + +static alpha_extra_func_info_t +push_sigtramp_desc (low_addr) + CORE_ADDR low_addr; +{ + struct linked_proc_info *link; + alpha_extra_func_info_t proc_desc; + + 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; + + proc_desc->numargs = 0; + PROC_LOW_ADDR (proc_desc) = low_addr; + PROC_HIGH_ADDR (proc_desc) = low_addr + 3 * 4; + PROC_DUMMY_FRAME (proc_desc) = 0; + PROC_FRAME_OFFSET (proc_desc) = 0x298; /* sizeof(struct sigcontext_struct) */ + PROC_FRAME_REG (proc_desc) = SP_REGNUM; + PROC_REG_MASK (proc_desc) = 0xffff; + PROC_FREG_MASK (proc_desc) = 0xffff; + PROC_PC_REG (proc_desc) = 26; + PROC_LOCALOFF (proc_desc) = 0; + SET_PROC_DESC_IS_DYN_SIGTRAMP (proc_desc); + return (proc_desc); +} + + +/* Guaranteed to set frame->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_zalloc (frame); + + /* If it is the frame for __sigtramp, the saved registers are located + in a sigcontext structure somewhere on the stack. __sigtramp + passes a pointer to the sigcontext structure 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) +#define SIGFRAME_FPREGSAVE_OFF (SIGFRAME_REGSAVE_OFF + 32 * 8 + 8) +#endif + if (frame->signal_handler_caller) + { + CORE_ADDR sigcontext_addr; + + sigcontext_addr = SIGCONTEXT_ADDR (frame); + for (ireg = 0; ireg < 32; ireg++) + { + reg_position = sigcontext_addr + SIGFRAME_REGSAVE_OFF + ireg * 8; + frame->saved_regs[ireg] = reg_position; + } + for (ireg = 0; ireg < 32; ireg++) + { + reg_position = sigcontext_addr + SIGFRAME_FPREGSAVE_OFF + ireg * 8; + frame->saved_regs[FP0_REGNUM + ireg] = reg_position; + } + frame->saved_regs[PC_REGNUM] = sigcontext_addr + SIGFRAME_PC_OFF; + return; + } + + 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 its actual + register number. */ + if (mask & (1 << returnreg)) + { + frame->saved_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[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[FP0_REGNUM+ireg] = reg_position; + reg_position += 8; + } + + frame->saved_regs[PC_REGNUM] = frame->saved_regs[returnreg]; +} + +static CORE_ADDR +read_next_frame_reg(fi, regno) + struct frame_info *fi; + int regno; +{ + for (; fi; fi = fi->next) + { + /* We have to get the saved sp from the sigcontext + if it is a signal handler frame. */ + if (regno == SP_REGNUM && !fi->signal_handler_caller) + return fi->frame; + else + { + if (fi->saved_regs == NULL) + alpha_find_saved_regs (fi); + if (fi->saved_regs[regno]) + return read_memory_integer(fi->saved_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 : frame->pc_reg; + + 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; +{ + CORE_ADDR pc = frame->pc; + CORE_ADDR tmp; + alpha_extra_func_info_t proc_desc; + int pcreg; + + /* Skip over shared library trampoline if necessary. */ + tmp = SKIP_TRAMPOLINE_CODE (pc); + if (tmp != 0) + pc = tmp; + + proc_desc = find_proc_desc (pc, frame->next); + pcreg = proc_desc ? PROC_PC_REG (proc_desc) : RA_REGNUM; + + if (frame->signal_handler_caller) + return alpha_frame_saved_pc (frame); + else + return read_register (pcreg); +} + + +static struct alpha_extra_func_info temp_proc_desc; +static struct frame_saved_regs temp_saved_regs; + +/* Nonzero if instruction at PC is a return instruction. "ret + $zero,($ra),1" on alpha. */ + +static int +alpha_about_to_return (pc) + CORE_ADDR pc; +{ + return read_memory_integer (pc, 4) == 0x6bfa8001; +} + + + +/* 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 (alpha_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; + int pcreg = -1; + + 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) */ + { + if (word & 0x8000) + frame_size += (-word) & 0xffff; + else + /* Exit loop if a positive stack adjustment is found, which + usually means that the stack cleanup code in the function + epilogue is reached. */ + break; + } + else if ((word & 0xfc1f0000) == 0xb41e0000 /* stq reg,n($sp) */ + && (word & 0xffff0000) != 0xb7fe0000) /* reg != $zero */ + { + int reg = (word & 0x03e00000) >> 21; + reg_mask |= 1 << reg; + temp_saved_regs.regs[reg] = sp + (short)word; + + /* Starting with OSF/1-3.2C, the system libraries are shipped + without local symbols, but they still contain procedure + descriptors without a symbol reference. GDB is currently + unable to find these procedure descriptors and uses + heuristic_proc_desc instead. + As some low level compiler support routines (__div*, __add*) + use a non-standard return address register, we have to + add some heuristics to determine the return address register, + or stepping over these routines will fail. + Usually the return address register is the first register + saved on the stack, but assembler optimization might + rearrange the register saves. + So we recognize only a few registers (t7, t9, ra) within + the procedure prologue as valid return address registers. + If we encounter a return instruction, we extract the + the return address register from it. + + FIXME: Rewriting GDB to access the procedure descriptors, + e.g. via the minimal symbol table, might obviate this hack. */ + if (pcreg == -1 + && cur_pc < (start_pc + 80) + && (reg == T7_REGNUM || reg == T9_REGNUM || reg == RA_REGNUM)) + pcreg = reg; + } + else if ((word & 0xffe0ffff) == 0x6be08001) /* ret zero,reg,1 */ + pcreg = (word >> 16) & 0x1f; + else if (word == 0x47de040f) /* bis sp,sp fp */ + has_frame_reg = 1; + } + if (pcreg == -1) + { + /* If we haven't found a valid return address register yet, + keep searching in the procedure prologue. */ + while (cur_pc < (limit_pc + 80) && cur_pc < (start_pc + 80)) + { + char buf[4]; + unsigned long word; + + if (read_memory_nobpt (cur_pc, buf, 4)) + break; + cur_pc += 4; + word = extract_unsigned_integer (buf, 4); + + if ((word & 0xfc1f0000) == 0xb41e0000 /* stq reg,n($sp) */ + && (word & 0xffff0000) != 0xb7fe0000) /* reg != $zero */ + { + int reg = (word & 0x03e00000) >> 21; + if (reg == T7_REGNUM || reg == T9_REGNUM || reg == RA_REGNUM) + { + pcreg = reg; + break; + } + } + else if ((word & 0xffe0ffff) == 0x6be08001) /* ret zero,reg,1 */ + { + pcreg = (word >> 16) & 0x1f; + break; + } + } + } + + 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) = (pcreg == -1) ? RA_REGNUM : pcreg; + 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 (PROC_DESC_IS_DYN_SIGTRAMP (proc_desc)) + return PROC_LOW_ADDR (proc_desc); /* "prologue" is in kernel */ + + /* 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 definitively *not* in a function prologue. */ + +static int +alpha_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 we never found a PDR for this function in symbol reading, then + examine prologues to find the information. */ + if (sym && ((mips_extra_func_info_t) SYMBOL_VALUE (sym))->pdr.framereg == -1) + sym = 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) || alpha_in_prologue (pc, proc_desc)) + { + alpha_extra_func_info_t found_heuristic = + heuristic_proc_desc (PROC_LOW_ADDR (proc_desc), + pc, next_frame); + if (found_heuristic) + { + PROC_LOCALOFF (found_heuristic) = + PROC_LOCALOFF (proc_desc); + PROC_PC_REG (found_heuristic) = PROC_PC_REG (proc_desc); + proc_desc = found_heuristic; + } + } + } + } + else + { + long offset; + + /* 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 PC is inside a dynamically generated sigtramp handler, + create and push a procedure descriptor for that code: */ + offset = DYNAMIC_SIGTRAMP_OFFSET (pc); + if (offset >= 0) + return push_sigtramp_desc (pc - offset); + + /* If heuristic_fence_post is non-zero, determine the procedure + start address by examining the instructions. + This allows us to find the start address of static functions which + have no symbolic information, as startaddr would have been set to + the preceding global function start address by the + find_pc_partial_function call above. */ + if (startaddr == 0 || heuristic_fence_post != 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) + return FRAME_PAST_SIGTRAMP_FRAME (frame, saved_pc); + 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->localoff = 0; + frame->pc_reg = RA_REGNUM; + frame->proc_desc = proc_desc == &temp_proc_desc ? 0 : proc_desc; + if (proc_desc) + { + /* Get the locals offset and the saved pc register from the + procedure descriptor, they are valid even if we are in the + middle of the prologue. */ + frame->localoff = PROC_LOCALOFF(proc_desc); + frame->pc_reg = PROC_PC_REG(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_DYN_SIGTRAMP (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) + { + char *name; + + /* Do not set the saved registers for a sigtramp frame, + alpha_find_saved_registers will do that for us. + We can't use frame->signal_handler_caller, it is not yet set. */ + find_pc_partial_function (frame->pc, &name, + (CORE_ADDR *)NULL,(CORE_ADDR *)NULL); + if (!IN_SIGTRAMP (frame->pc, name)) + { + frame->saved_regs = (CORE_ADDR*) + frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS); + memcpy (frame->saved_regs, temp_saved_regs.regs, SIZEOF_FRAME_SAVED_REGS); + frame->saved_regs[PC_REGNUM] + = frame->saved_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 = args[i]; + struct type *arg_type = check_typedef (VALUE_TYPE (arg)); + /* Cast argument to long if necessary as the compiler does it too. */ + switch (TYPE_CODE (arg_type)) + { + case TYPE_CODE_INT: + case TYPE_CODE_BOOL: + case TYPE_CODE_CHAR: + case TYPE_CODE_RANGE: + case TYPE_CODE_ENUM: + if (TYPE_LENGTH (arg_type) < TYPE_LENGTH (builtin_type_long)) + { + arg_type = builtin_type_long; + arg = value_cast (arg_type, arg); + } + break; + default: + break; + } + m_arg->len = TYPE_LENGTH (arg_type); + 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) ((((LONGEST)1 << ((j)+1)) - 1) ^ (((LONGEST)1 << (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[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[regnum + FP0_REGNUM], 8)); + } + write_register (SP_REGNUM, new_sp); + flush_cached_frames (); + + if (proc_desc && (PROC_DESC_IS_DUMMY(proc_desc) + || PROC_DESC_IS_DYN_SIGTRAMP (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) + { + ULONGEST 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) + { + ULONGEST 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; +{ + if (TYPE_CODE (valtype) == TYPE_CODE_FLT) + alpha_register_convert_to_virtual (FP0_REGNUM, valtype, + regbuf + REGISTER_BYTE (FP0_REGNUM), + valbuf); + else + memcpy (valbuf, regbuf + REGISTER_BYTE (V0_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; +{ + char raw_buffer[MAX_REGISTER_RAW_SIZE]; + int regnum = V0_REGNUM; + int length = TYPE_LENGTH (valtype); + + if (TYPE_CODE (valtype) == TYPE_CODE_FLT) + { + regnum = FP0_REGNUM; + length = REGISTER_RAW_SIZE (regnum); + alpha_register_convert_to_raw (valtype, regnum, valbuf, raw_buffer); + } + else + memcpy (raw_buffer, valbuf, length); + + write_register_bytes (REGISTER_BYTE (regnum), raw_buffer, length); +} + +/* 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); +} |