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d2427a71 1/* Target-dependent mdebug code for the ALPHA architecture.
6aba47ca
DJ
2 Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
3 2003, 2007 Free Software Foundation, Inc.
d2427a71
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4
5 This file is part of GDB.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
197e01b6
EZ
19 Foundation, Inc., 51 Franklin Street, Fifth Floor,
20 Boston, MA 02110-1301, USA. */
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21
22#include "defs.h"
23#include "frame.h"
24#include "frame-unwind.h"
25#include "frame-base.h"
d2427a71 26#include "symtab.h"
d2427a71 27#include "gdbcore.h"
d2427a71
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28#include "block.h"
29#include "gdb_assert.h"
30
d2427a71 31#include "alpha-tdep.h"
5f6a2351 32#include "mdebugread.h"
d2427a71
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33
34/* FIXME: Some of this code should perhaps be merged with mips. */
35
36/* *INDENT-OFF* */
37/* Layout of a stack frame on the alpha:
38
39 | |
40 pdr members: | 7th ... nth arg, |
41 | `pushed' by caller. |
42 | |
43----------------|-------------------------------|<-- old_sp == vfp
44 ^ ^ ^ ^ | |
45 | | | | | |
46 | |localoff | Copies of 1st .. 6th |
47 | | | | | argument if necessary. |
48 | | | v | |
42efa47a 49 | | | --- |-------------------------------|<-- LOCALS_ADDRESS
d2427a71
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50 | | | | |
51 | | | | Locals and temporaries. |
52 | | | | |
53 | | | |-------------------------------|
54 | | | | |
55 |-fregoffset | Saved float registers. |
56 | | | | F9 |
57 | | | | . |
58 | | | | . |
59 | | | | F2 |
60 | | v | |
61 | | -------|-------------------------------|
62 | | | |
63 | | | Saved registers. |
64 | | | S6 |
65 |-regoffset | . |
66 | | | . |
67 | | | S0 |
68 | | | pdr.pcreg |
69 | v | |
70 | ----------|-------------------------------|
71 | | |
72 frameoffset | Argument build area, gets |
73 | | 7th ... nth arg for any |
74 | | called procedure. |
75 v | |
76 -------------|-------------------------------|<-- sp
77 | |
78*/
79/* *INDENT-ON* */
80
81#define PROC_LOW_ADDR(proc) ((proc)->pdr.adr)
82#define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset)
83#define PROC_FRAME_REG(proc) ((proc)->pdr.framereg)
84#define PROC_REG_MASK(proc) ((proc)->pdr.regmask)
85#define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask)
86#define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset)
87#define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset)
88#define PROC_PC_REG(proc) ((proc)->pdr.pcreg)
89#define PROC_LOCALOFF(proc) ((proc)->pdr.localoff)
90\f
91/* Locate the mdebug PDR for the given PC. Return null if one can't
92 be found; you'll have to fall back to other methods in that case. */
93
5f6a2351 94static struct mdebug_extra_func_info *
d2427a71
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95find_proc_desc (CORE_ADDR pc)
96{
97 struct block *b = block_for_pc (pc);
5f6a2351 98 struct mdebug_extra_func_info *proc_desc = NULL;
d2427a71
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99 struct symbol *sym = NULL;
100
101 if (b)
102 {
103 CORE_ADDR startaddr;
104 find_pc_partial_function (pc, NULL, &startaddr, NULL);
105
106 if (startaddr > BLOCK_START (b))
107 /* This is the "pathological" case referred to in a comment in
108 print_frame_info. It might be better to move this check into
109 symbol reading. */
110 sym = NULL;
111 else
f92761ec 112 sym = lookup_symbol (MDEBUG_EFI_SYMBOL_NAME, b, LABEL_DOMAIN, 0, NULL);
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113 }
114
115 if (sym)
116 {
5f6a2351 117 proc_desc = (struct mdebug_extra_func_info *) SYMBOL_VALUE (sym);
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118
119 /* If we never found a PDR for this function in symbol reading,
120 then examine prologues to find the information. */
121 if (proc_desc->pdr.framereg == -1)
122 proc_desc = NULL;
123 }
124
125 return proc_desc;
126}
127
128/* This returns the PC of the first inst after the prologue. If we can't
129 find the prologue, then return 0. */
130
131static CORE_ADDR
5f6a2351 132alpha_mdebug_after_prologue (CORE_ADDR pc, struct mdebug_extra_func_info *proc_desc)
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133{
134 if (proc_desc)
135 {
136 /* If function is frameless, then we need to do it the hard way. I
137 strongly suspect that frameless always means prologueless... */
087779b1 138 if (PROC_FRAME_REG (proc_desc) == ALPHA_SP_REGNUM
d2427a71
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139 && PROC_FRAME_OFFSET (proc_desc) == 0)
140 return 0;
141 }
142
143 return alpha_after_prologue (pc);
144}
145
146/* Return non-zero if we *might* be in a function prologue. Return zero
147 if we are definitively *not* in a function prologue. */
148
149static int
5f6a2351 150alpha_mdebug_in_prologue (CORE_ADDR pc, struct mdebug_extra_func_info *proc_desc)
d2427a71
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151{
152 CORE_ADDR after_prologue_pc = alpha_mdebug_after_prologue (pc, proc_desc);
153 return (after_prologue_pc == 0 || pc < after_prologue_pc);
154}
155
156\f
157/* Frame unwinder that reads mdebug PDRs. */
158
159struct alpha_mdebug_unwind_cache
160{
5f6a2351 161 struct mdebug_extra_func_info *proc_desc;
d2427a71
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162 CORE_ADDR vfp;
163 CORE_ADDR *saved_regs;
d2427a71
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164};
165
166/* Extract all of the information about the frame from PROC_DESC
167 and store the resulting register save locations in the structure. */
168
169static struct alpha_mdebug_unwind_cache *
170alpha_mdebug_frame_unwind_cache (struct frame_info *next_frame,
171 void **this_prologue_cache)
172{
173 struct alpha_mdebug_unwind_cache *info;
5f6a2351 174 struct mdebug_extra_func_info *proc_desc;
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175 ULONGEST vfp;
176 CORE_ADDR pc, reg_position;
177 unsigned long mask;
178 int ireg, returnreg;
179
180 if (*this_prologue_cache)
181 return *this_prologue_cache;
182
183 info = FRAME_OBSTACK_ZALLOC (struct alpha_mdebug_unwind_cache);
184 *this_prologue_cache = info;
185 pc = frame_pc_unwind (next_frame);
186
187 /* ??? We don't seem to be able to cache the lookup of the PDR
188 from alpha_mdebug_frame_p. It'd be nice if we could change
189 the arguments to that function. Oh well. */
190 proc_desc = find_proc_desc (pc);
191 info->proc_desc = proc_desc;
192 gdb_assert (proc_desc != NULL);
193
d2427a71
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194 info->saved_regs = frame_obstack_zalloc (SIZEOF_FRAME_SAVED_REGS);
195
196 /* The VFP of the frame is at FRAME_REG+FRAME_OFFSET. */
197 frame_unwind_unsigned_register (next_frame, PROC_FRAME_REG (proc_desc), &vfp);
198 vfp += PROC_FRAME_OFFSET (info->proc_desc);
199 info->vfp = vfp;
200
201 /* Fill in the offsets for the registers which gen_mask says were saved. */
202
203 reg_position = vfp + PROC_REG_OFFSET (proc_desc);
204 mask = PROC_REG_MASK (proc_desc);
205 returnreg = PROC_PC_REG (proc_desc);
206
207 /* Note that RA is always saved first, regardless of its actual
208 register number. */
209 if (mask & (1 << returnreg))
210 {
211 /* Clear bit for RA so we don't save it again later. */
212 mask &= ~(1 << returnreg);
213
214 info->saved_regs[returnreg] = reg_position;
215 reg_position += 8;
216 }
217
218 for (ireg = 0; ireg <= 31; ++ireg)
219 if (mask & (1 << ireg))
220 {
221 info->saved_regs[ireg] = reg_position;
222 reg_position += 8;
223 }
224
225 reg_position = vfp + PROC_FREG_OFFSET (proc_desc);
226 mask = PROC_FREG_MASK (proc_desc);
227
228 for (ireg = 0; ireg <= 31; ++ireg)
229 if (mask & (1 << ireg))
230 {
087779b1 231 info->saved_regs[ALPHA_FP0_REGNUM + ireg] = reg_position;
d2427a71
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232 reg_position += 8;
233 }
234
235 return info;
236}
237
238/* Given a GDB frame, determine the address of the calling function's
239 frame. This will be used to create a new GDB frame struct. */
240
241static void
242alpha_mdebug_frame_this_id (struct frame_info *next_frame,
243 void **this_prologue_cache,
244 struct frame_id *this_id)
245{
246 struct alpha_mdebug_unwind_cache *info
247 = alpha_mdebug_frame_unwind_cache (next_frame, this_prologue_cache);
248
fbe586ae 249 *this_id = frame_id_build (info->vfp, frame_func_unwind (next_frame));
d2427a71
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250}
251
252/* Retrieve the value of REGNUM in FRAME. Don't give up! */
253
254static void
255alpha_mdebug_frame_prev_register (struct frame_info *next_frame,
256 void **this_prologue_cache,
257 int regnum, int *optimizedp,
258 enum lval_type *lvalp, CORE_ADDR *addrp,
5b819568 259 int *realnump, gdb_byte *bufferp)
d2427a71
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260{
261 struct alpha_mdebug_unwind_cache *info
262 = alpha_mdebug_frame_unwind_cache (next_frame, this_prologue_cache);
263
d2427a71
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264 /* The PC of the previous frame is stored in the link register of
265 the current frame. Frob regnum so that we pull the value from
266 the correct place. */
087779b1 267 if (regnum == ALPHA_PC_REGNUM)
d2427a71
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268 regnum = PROC_PC_REG (info->proc_desc);
269
270 /* For all registers known to be saved in the current frame,
271 do the obvious and pull the value out. */
272 if (info->saved_regs[regnum])
273 {
274 *optimizedp = 0;
275 *lvalp = lval_memory;
276 *addrp = info->saved_regs[regnum];
277 *realnump = -1;
278 if (bufferp != NULL)
b21fd293 279 get_frame_memory (next_frame, *addrp, bufferp, ALPHA_REGISTER_SIZE);
d2427a71
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280 return;
281 }
282
283 /* The stack pointer of the previous frame is computed by popping
284 the current stack frame. */
087779b1 285 if (regnum == ALPHA_SP_REGNUM)
d2427a71
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286 {
287 *optimizedp = 0;
288 *lvalp = not_lval;
289 *addrp = 0;
290 *realnump = -1;
291 if (bufferp != NULL)
292 store_unsigned_integer (bufferp, ALPHA_REGISTER_SIZE, info->vfp);
293 return;
294 }
295
296 /* Otherwise assume the next frame has the same register value. */
297 frame_register (next_frame, regnum, optimizedp, lvalp, addrp,
298 realnump, bufferp);
299}
300
301static const struct frame_unwind alpha_mdebug_frame_unwind = {
302 NORMAL_FRAME,
303 alpha_mdebug_frame_this_id,
304 alpha_mdebug_frame_prev_register
305};
306
307const struct frame_unwind *
336d1bba 308alpha_mdebug_frame_sniffer (struct frame_info *next_frame)
d2427a71 309{
336d1bba 310 CORE_ADDR pc = frame_pc_unwind (next_frame);
5f6a2351 311 struct mdebug_extra_func_info *proc_desc;
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312
313 /* If this PC does not map to a PDR, then clearly this isn't an
314 mdebug frame. */
315 proc_desc = find_proc_desc (pc);
316 if (proc_desc == NULL)
317 return NULL;
318
fbe586ae
RH
319 /* If we're in the prologue, the PDR for this frame is not yet valid.
320 Say no here and we'll fall back on the heuristic unwinder. */
321 if (alpha_mdebug_in_prologue (pc, proc_desc))
322 return NULL;
323
d2427a71
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324 return &alpha_mdebug_frame_unwind;
325}
326
327static CORE_ADDR
328alpha_mdebug_frame_base_address (struct frame_info *next_frame,
329 void **this_prologue_cache)
330{
331 struct alpha_mdebug_unwind_cache *info
332 = alpha_mdebug_frame_unwind_cache (next_frame, this_prologue_cache);
333
fbe586ae 334 return info->vfp;
d2427a71
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335}
336
337static CORE_ADDR
338alpha_mdebug_frame_locals_address (struct frame_info *next_frame,
339 void **this_prologue_cache)
340{
341 struct alpha_mdebug_unwind_cache *info
342 = alpha_mdebug_frame_unwind_cache (next_frame, this_prologue_cache);
d2427a71 343
fbe586ae 344 return info->vfp - PROC_LOCALOFF (info->proc_desc);
d2427a71
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345}
346
347static CORE_ADDR
348alpha_mdebug_frame_args_address (struct frame_info *next_frame,
349 void **this_prologue_cache)
350{
351 struct alpha_mdebug_unwind_cache *info
352 = alpha_mdebug_frame_unwind_cache (next_frame, this_prologue_cache);
d2427a71 353
fbe586ae 354 return info->vfp - ALPHA_NUM_ARG_REGS * 8;
d2427a71
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355}
356
357static const struct frame_base alpha_mdebug_frame_base = {
358 &alpha_mdebug_frame_unwind,
359 alpha_mdebug_frame_base_address,
360 alpha_mdebug_frame_locals_address,
361 alpha_mdebug_frame_args_address
362};
363
364static const struct frame_base *
336d1bba 365alpha_mdebug_frame_base_sniffer (struct frame_info *next_frame)
d2427a71 366{
336d1bba 367 CORE_ADDR pc = frame_pc_unwind (next_frame);
5f6a2351 368 struct mdebug_extra_func_info *proc_desc;
d2427a71
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369
370 /* If this PC does not map to a PDR, then clearly this isn't an
371 mdebug frame. */
372 proc_desc = find_proc_desc (pc);
373 if (proc_desc == NULL)
374 return NULL;
375
376 return &alpha_mdebug_frame_base;
377}
378
379\f
380void
381alpha_mdebug_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
382{
383 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
384
336d1bba
AC
385 frame_unwind_append_sniffer (gdbarch, alpha_mdebug_frame_sniffer);
386 frame_base_append_sniffer (gdbarch, alpha_mdebug_frame_base_sniffer);
d2427a71 387}