1 /* Target-dependent mdebug code for the ALPHA architecture.
2 Copyright (C) 1993-2014 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 #include "frame-unwind.h"
22 #include "frame-base.h"
27 #include "trad-frame.h"
29 #include "alpha-tdep.h"
30 #include "mdebugread.h"
32 /* FIXME: Some of this code should perhaps be merged with mips. */
35 /* Layout of a stack frame on the alpha:
38 pdr members: | 7th ... nth arg, |
39 | `pushed' by caller. |
41 ----------------|-------------------------------|<-- old_sp == vfp
44 | |localoff | Copies of 1st .. 6th |
45 | | | | | argument if necessary. |
47 | | | --- |-------------------------------|<-- LOCALS_ADDRESS
49 | | | | Locals and temporaries. |
51 | | | |-------------------------------|
53 |-fregoffset | Saved float registers. |
59 | | -------|-------------------------------|
61 | | | Saved registers. |
68 | ----------|-------------------------------|
70 frameoffset | Argument build area, gets |
71 | | 7th ... nth arg for any |
72 | | called procedure. |
74 -------------|-------------------------------|<-- sp
79 #define PROC_LOW_ADDR(proc) ((proc)->pdr.adr)
80 #define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset)
81 #define PROC_FRAME_REG(proc) ((proc)->pdr.framereg)
82 #define PROC_REG_MASK(proc) ((proc)->pdr.regmask)
83 #define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask)
84 #define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset)
85 #define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset)
86 #define PROC_PC_REG(proc) ((proc)->pdr.pcreg)
87 #define PROC_LOCALOFF(proc) ((proc)->pdr.localoff)
89 /* Locate the mdebug PDR for the given PC. Return null if one can't
90 be found; you'll have to fall back to other methods in that case. */
92 static struct mdebug_extra_func_info *
93 find_proc_desc (CORE_ADDR pc)
95 const struct block *b = block_for_pc (pc);
96 struct mdebug_extra_func_info *proc_desc = NULL;
97 struct symbol *sym = NULL;
98 const char *sh_name = NULL;
103 find_pc_partial_function (pc, &sh_name, &startaddr, NULL);
105 if (startaddr > BLOCK_START (b))
106 /* This is the "pathological" case referred to in a comment in
107 print_frame_info. It might be better to move this check into
111 sym = lookup_symbol (MDEBUG_EFI_SYMBOL_NAME, b, LABEL_DOMAIN, 0);
116 proc_desc = (struct mdebug_extra_func_info *) SYMBOL_VALUE_BYTES (sym);
118 /* Correct incorrect setjmp procedure descriptor from the library
119 to make backtrace through setjmp work. */
120 if (proc_desc->pdr.pcreg == 0
121 && strcmp (sh_name, "setjmp") == 0)
123 proc_desc->pdr.pcreg = ALPHA_RA_REGNUM;
124 proc_desc->pdr.regmask = 0x80000000;
125 proc_desc->pdr.regoffset = -4;
128 /* If we never found a PDR for this function in symbol reading,
129 then examine prologues to find the information. */
130 if (proc_desc->pdr.framereg == -1)
137 /* Return a non-zero result if the function is frameless; zero otherwise. */
140 alpha_mdebug_frameless (struct mdebug_extra_func_info *proc_desc)
142 return (PROC_FRAME_REG (proc_desc) == ALPHA_SP_REGNUM
143 && PROC_FRAME_OFFSET (proc_desc) == 0);
146 /* This returns the PC of the first inst after the prologue. If we can't
147 find the prologue, then return 0. */
150 alpha_mdebug_after_prologue (CORE_ADDR pc,
151 struct mdebug_extra_func_info *proc_desc)
155 /* If function is frameless, then we need to do it the hard way. I
156 strongly suspect that frameless always means prologueless... */
157 if (alpha_mdebug_frameless (proc_desc))
161 return alpha_after_prologue (pc);
164 /* Return non-zero if we *might* be in a function prologue. Return zero
165 if we are definitively *not* in a function prologue. */
168 alpha_mdebug_in_prologue (CORE_ADDR pc,
169 struct mdebug_extra_func_info *proc_desc)
171 CORE_ADDR after_prologue_pc = alpha_mdebug_after_prologue (pc, proc_desc);
172 return (after_prologue_pc == 0 || pc < after_prologue_pc);
176 /* Frame unwinder that reads mdebug PDRs. */
178 struct alpha_mdebug_unwind_cache
180 struct mdebug_extra_func_info *proc_desc;
182 struct trad_frame_saved_reg *saved_regs;
185 /* Extract all of the information about the frame from PROC_DESC
186 and store the resulting register save locations in the structure. */
188 static struct alpha_mdebug_unwind_cache *
189 alpha_mdebug_frame_unwind_cache (struct frame_info *this_frame,
190 void **this_prologue_cache)
192 struct alpha_mdebug_unwind_cache *info;
193 struct mdebug_extra_func_info *proc_desc;
195 CORE_ADDR pc, reg_position;
199 if (*this_prologue_cache)
200 return *this_prologue_cache;
202 info = FRAME_OBSTACK_ZALLOC (struct alpha_mdebug_unwind_cache);
203 *this_prologue_cache = info;
204 pc = get_frame_address_in_block (this_frame);
206 /* ??? We don't seem to be able to cache the lookup of the PDR
207 from alpha_mdebug_frame_p. It'd be nice if we could change
208 the arguments to that function. Oh well. */
209 proc_desc = find_proc_desc (pc);
210 info->proc_desc = proc_desc;
211 gdb_assert (proc_desc != NULL);
213 info->saved_regs = trad_frame_alloc_saved_regs (this_frame);
215 /* The VFP of the frame is at FRAME_REG+FRAME_OFFSET. */
216 vfp = get_frame_register_unsigned (this_frame, PROC_FRAME_REG (proc_desc));
217 vfp += PROC_FRAME_OFFSET (info->proc_desc);
220 /* Fill in the offsets for the registers which gen_mask says were saved. */
222 reg_position = vfp + PROC_REG_OFFSET (proc_desc);
223 mask = PROC_REG_MASK (proc_desc);
224 returnreg = PROC_PC_REG (proc_desc);
226 /* Note that RA is always saved first, regardless of its actual
228 if (mask & (1 << returnreg))
230 /* Clear bit for RA so we don't save it again later. */
231 mask &= ~(1 << returnreg);
233 info->saved_regs[returnreg].addr = reg_position;
237 for (ireg = 0; ireg <= 31; ++ireg)
238 if (mask & (1 << ireg))
240 info->saved_regs[ireg].addr = reg_position;
244 reg_position = vfp + PROC_FREG_OFFSET (proc_desc);
245 mask = PROC_FREG_MASK (proc_desc);
247 for (ireg = 0; ireg <= 31; ++ireg)
248 if (mask & (1 << ireg))
250 info->saved_regs[ALPHA_FP0_REGNUM + ireg].addr = reg_position;
254 /* The stack pointer of the previous frame is computed by popping
255 the current stack frame. */
256 if (!trad_frame_addr_p (info->saved_regs, ALPHA_SP_REGNUM))
257 trad_frame_set_value (info->saved_regs, ALPHA_SP_REGNUM, vfp);
262 /* Given a GDB frame, determine the address of the calling function's
263 frame. This will be used to create a new GDB frame struct. */
266 alpha_mdebug_frame_this_id (struct frame_info *this_frame,
267 void **this_prologue_cache,
268 struct frame_id *this_id)
270 struct alpha_mdebug_unwind_cache *info
271 = alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache);
273 *this_id = frame_id_build (info->vfp, get_frame_func (this_frame));
276 /* Retrieve the value of REGNUM in FRAME. Don't give up! */
278 static struct value *
279 alpha_mdebug_frame_prev_register (struct frame_info *this_frame,
280 void **this_prologue_cache, int regnum)
282 struct alpha_mdebug_unwind_cache *info
283 = alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache);
285 /* The PC of the previous frame is stored in the link register of
286 the current frame. Frob regnum so that we pull the value from
287 the correct place. */
288 if (regnum == ALPHA_PC_REGNUM)
289 regnum = PROC_PC_REG (info->proc_desc);
291 return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
294 /* Return a non-zero result if the size of the stack frame exceeds the
295 maximum debuggable frame size (512 Kbytes); zero otherwise. */
298 alpha_mdebug_max_frame_size_exceeded (struct mdebug_extra_func_info *proc_desc)
300 /* If frame offset is null, we can be in two cases: either the
301 function is frameless (the stack frame is null) or its
302 frame exceeds the maximum debuggable frame size (512 Kbytes). */
304 return (PROC_FRAME_OFFSET (proc_desc) == 0
305 && !alpha_mdebug_frameless (proc_desc));
309 alpha_mdebug_frame_sniffer (const struct frame_unwind *self,
310 struct frame_info *this_frame,
313 CORE_ADDR pc = get_frame_address_in_block (this_frame);
314 struct mdebug_extra_func_info *proc_desc;
316 /* If this PC does not map to a PDR, then clearly this isn't an
318 proc_desc = find_proc_desc (pc);
319 if (proc_desc == NULL)
322 /* If we're in the prologue, the PDR for this frame is not yet valid.
323 Say no here and we'll fall back on the heuristic unwinder. */
324 if (alpha_mdebug_in_prologue (pc, proc_desc))
327 /* If the maximum debuggable frame size has been exceeded, the
328 proc desc is bogus. Fall back on the heuristic unwinder. */
329 if (alpha_mdebug_max_frame_size_exceeded (proc_desc))
335 static const struct frame_unwind alpha_mdebug_frame_unwind = {
337 default_frame_unwind_stop_reason,
338 alpha_mdebug_frame_this_id,
339 alpha_mdebug_frame_prev_register,
341 alpha_mdebug_frame_sniffer
345 alpha_mdebug_frame_base_address (struct frame_info *this_frame,
346 void **this_prologue_cache)
348 struct alpha_mdebug_unwind_cache *info
349 = alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache);
355 alpha_mdebug_frame_locals_address (struct frame_info *this_frame,
356 void **this_prologue_cache)
358 struct alpha_mdebug_unwind_cache *info
359 = alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache);
361 return info->vfp - PROC_LOCALOFF (info->proc_desc);
365 alpha_mdebug_frame_args_address (struct frame_info *this_frame,
366 void **this_prologue_cache)
368 struct alpha_mdebug_unwind_cache *info
369 = alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache);
371 return info->vfp - ALPHA_NUM_ARG_REGS * 8;
374 static const struct frame_base alpha_mdebug_frame_base = {
375 &alpha_mdebug_frame_unwind,
376 alpha_mdebug_frame_base_address,
377 alpha_mdebug_frame_locals_address,
378 alpha_mdebug_frame_args_address
381 static const struct frame_base *
382 alpha_mdebug_frame_base_sniffer (struct frame_info *this_frame)
384 CORE_ADDR pc = get_frame_address_in_block (this_frame);
385 struct mdebug_extra_func_info *proc_desc;
387 /* If this PC does not map to a PDR, then clearly this isn't an
389 proc_desc = find_proc_desc (pc);
390 if (proc_desc == NULL)
393 /* If the maximum debuggable frame size has been exceeded, the
394 proc desc is bogus. Fall back on the heuristic unwinder. */
395 if (alpha_mdebug_max_frame_size_exceeded (proc_desc))
398 return &alpha_mdebug_frame_base;
403 alpha_mdebug_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
405 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
407 frame_unwind_append_unwinder (gdbarch, &alpha_mdebug_frame_unwind);
408 frame_base_append_sniffer (gdbarch, alpha_mdebug_frame_base_sniffer);