1 
2 /*---------------------------------------------------------------*/
3 /*--- begin                               guest_arm_helpers.c ---*/
4 /*---------------------------------------------------------------*/
5 
6 /*
7    This file is part of Valgrind, a dynamic binary instrumentation
8    framework.
9 
10    Copyright (C) 2004-2013 OpenWorks LLP
11       info@open-works.net
12 
13    This program is free software; you can redistribute it and/or
14    modify it under the terms of the GNU General Public License as
15    published by the Free Software Foundation; either version 2 of the
16    License, or (at your option) any later version.
17 
18    This program is distributed in the hope that it will be useful, but
19    WITHOUT ANY WARRANTY; without even the implied warranty of
20    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21    General Public License for more details.
22 
23    You should have received a copy of the GNU General Public License
24    along with this program; if not, write to the Free Software
25    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
26    02110-1301, USA.
27 
28    The GNU General Public License is contained in the file COPYING.
29 */
30 
31 #include "libvex_basictypes.h"
32 #include "libvex_emnote.h"
33 #include "libvex_guest_arm.h"
34 #include "libvex_ir.h"
35 #include "libvex.h"
36 
37 #include "main_util.h"
38 #include "main_globals.h"
39 #include "guest_generic_bb_to_IR.h"
40 #include "guest_arm_defs.h"
41 
42 
43 /* This file contains helper functions for arm guest code.  Calls to
44    these functions are generated by the back end.  These calls are of
45    course in the host machine code and this file will be compiled to
46    host machine code, so that all makes sense.
47 
48    Only change the signatures of these helper functions very
49    carefully.  If you change the signature here, you'll have to change
50    the parameters passed to it in the IR calls constructed by
51    guest-arm/toIR.c.
52 */
53 
54 
55 /* Set to 1 to get detailed profiling info about individual N, Z, C
56    and V flag evaluation. */
57 #define PROFILE_NZCV_FLAGS 0
58 
59 #if PROFILE_NZCV_FLAGS
60 
61 static UInt tab_n_eval[ARMG_CC_OP_NUMBER];
62 static UInt tab_z_eval[ARMG_CC_OP_NUMBER];
63 static UInt tab_c_eval[ARMG_CC_OP_NUMBER];
64 static UInt tab_v_eval[ARMG_CC_OP_NUMBER];
65 static UInt initted = 0;
66 static UInt tot_evals = 0;
67 
initCounts(void)68 static void initCounts ( void )
69 {
70    UInt i;
71    for (i = 0; i < ARMG_CC_OP_NUMBER; i++) {
72       tab_n_eval[i] = tab_z_eval[i] = tab_c_eval[i] = tab_v_eval[i] = 0;
73    }
74    initted = 1;
75 }
76 
showCounts(void)77 static void showCounts ( void )
78 {
79    UInt i;
80    vex_printf("\n                 N          Z          C          V\n");
81    vex_printf(  "---------------------------------------------------\n");
82    for (i = 0; i < ARMG_CC_OP_NUMBER; i++) {
83       vex_printf("CC_OP=%d  %9d  %9d  %9d  %9d\n",
84                  i,
85                  tab_n_eval[i], tab_z_eval[i],
86                  tab_c_eval[i], tab_v_eval[i] );
87     }
88 }
89 
90 #define NOTE_N_EVAL(_cc_op) NOTE_EVAL(_cc_op, tab_n_eval)
91 #define NOTE_Z_EVAL(_cc_op) NOTE_EVAL(_cc_op, tab_z_eval)
92 #define NOTE_C_EVAL(_cc_op) NOTE_EVAL(_cc_op, tab_c_eval)
93 #define NOTE_V_EVAL(_cc_op) NOTE_EVAL(_cc_op, tab_v_eval)
94 
95 #define NOTE_EVAL(_cc_op, _tab) \
96    do { \
97       if (!initted) initCounts(); \
98       vassert( ((UInt)(_cc_op)) < ARMG_CC_OP_NUMBER); \
99       _tab[(UInt)(_cc_op)]++; \
100       tot_evals++; \
101       if (0 == (tot_evals & 0xFFFFF)) \
102         showCounts(); \
103    } while (0)
104 
105 #endif /* PROFILE_NZCV_FLAGS */
106 
107 
108 /* Calculate the N flag from the supplied thunk components, in the
109    least significant bit of the word.  Returned bits 31:1 are zero. */
110 static
armg_calculate_flag_n(UInt cc_op,UInt cc_dep1,UInt cc_dep2,UInt cc_dep3)111 UInt armg_calculate_flag_n ( UInt cc_op, UInt cc_dep1,
112                              UInt cc_dep2, UInt cc_dep3 )
113 {
114 #  if PROFILE_NZCV_FLAGS
115    NOTE_N_EVAL(cc_op);
116 #  endif
117 
118    switch (cc_op) {
119       case ARMG_CC_OP_COPY: {
120          /* (nzcv:28x0, unused, unused) */
121          UInt nf   = (cc_dep1 >> ARMG_CC_SHIFT_N) & 1;
122          return nf;
123       }
124       case ARMG_CC_OP_ADD: {
125          /* (argL, argR, unused) */
126          UInt argL = cc_dep1;
127          UInt argR = cc_dep2;
128          UInt res  = argL + argR;
129          UInt nf   = res >> 31;
130          return nf;
131       }
132       case ARMG_CC_OP_SUB: {
133          /* (argL, argR, unused) */
134          UInt argL = cc_dep1;
135          UInt argR = cc_dep2;
136          UInt res  = argL - argR;
137          UInt nf   = res >> 31;
138          return nf;
139       }
140       case ARMG_CC_OP_ADC: {
141          /* (argL, argR, oldC) */
142          UInt argL = cc_dep1;
143          UInt argR = cc_dep2;
144          UInt oldC = cc_dep3;
145          vassert((oldC & ~1) == 0);
146          UInt res  = argL + argR + oldC;
147          UInt nf   = res >> 31;
148          return nf;
149       }
150       case ARMG_CC_OP_SBB: {
151          /* (argL, argR, oldC) */
152          UInt argL = cc_dep1;
153          UInt argR = cc_dep2;
154          UInt oldC = cc_dep3;
155          vassert((oldC & ~1) == 0);
156          UInt res  = argL - argR - (oldC ^ 1);
157          UInt nf   = res >> 31;
158          return nf;
159       }
160       case ARMG_CC_OP_LOGIC: {
161          /* (res, shco, oldV) */
162          UInt res  = cc_dep1;
163          UInt nf   = res >> 31;
164          return nf;
165       }
166       case ARMG_CC_OP_MUL: {
167          /* (res, unused, oldC:oldV) */
168          UInt res  = cc_dep1;
169          UInt nf   = res >> 31;
170          return nf;
171       }
172       case ARMG_CC_OP_MULL: {
173          /* (resLo32, resHi32, oldC:oldV) */
174          UInt resHi32 = cc_dep2;
175          UInt nf      = resHi32 >> 31;
176          return nf;
177       }
178       default:
179          /* shouldn't really make these calls from generated code */
180          vex_printf("armg_calculate_flag_n"
181                     "( op=%u, dep1=0x%x, dep2=0x%x, dep3=0x%x )\n",
182                     cc_op, cc_dep1, cc_dep2, cc_dep3 );
183          vpanic("armg_calculate_flags_n");
184    }
185 }
186 
187 
188 /* Calculate the Z flag from the supplied thunk components, in the
189    least significant bit of the word.  Returned bits 31:1 are zero. */
190 static
armg_calculate_flag_z(UInt cc_op,UInt cc_dep1,UInt cc_dep2,UInt cc_dep3)191 UInt armg_calculate_flag_z ( UInt cc_op, UInt cc_dep1,
192                              UInt cc_dep2, UInt cc_dep3 )
193 {
194 #  if PROFILE_NZCV_FLAGS
195    NOTE_Z_EVAL(cc_op);
196 #  endif
197 
198    switch (cc_op) {
199       case ARMG_CC_OP_COPY: {
200          /* (nzcv:28x0, unused, unused) */
201          UInt zf   = (cc_dep1 >> ARMG_CC_SHIFT_Z) & 1;
202          return zf;
203       }
204       case ARMG_CC_OP_ADD: {
205          /* (argL, argR, unused) */
206          UInt argL = cc_dep1;
207          UInt argR = cc_dep2;
208          UInt res  = argL + argR;
209          UInt zf   = res == 0;
210          return zf;
211       }
212       case ARMG_CC_OP_SUB: {
213          /* (argL, argR, unused) */
214          UInt argL = cc_dep1;
215          UInt argR = cc_dep2;
216          UInt res  = argL - argR;
217          UInt zf   = res == 0;
218          return zf;
219       }
220       case ARMG_CC_OP_ADC: {
221          /* (argL, argR, oldC) */
222          UInt argL = cc_dep1;
223          UInt argR = cc_dep2;
224          UInt oldC = cc_dep3;
225          vassert((oldC & ~1) == 0);
226          UInt res  = argL + argR + oldC;
227          UInt zf   = res == 0;
228          return zf;
229       }
230       case ARMG_CC_OP_SBB: {
231          /* (argL, argR, oldC) */
232          UInt argL = cc_dep1;
233          UInt argR = cc_dep2;
234          UInt oldC = cc_dep3;
235          vassert((oldC & ~1) == 0);
236          UInt res  = argL - argR - (oldC ^ 1);
237          UInt zf   = res == 0;
238          return zf;
239       }
240       case ARMG_CC_OP_LOGIC: {
241          /* (res, shco, oldV) */
242          UInt res  = cc_dep1;
243          UInt zf   = res == 0;
244          return zf;
245       }
246       case ARMG_CC_OP_MUL: {
247          /* (res, unused, oldC:oldV) */
248          UInt res  = cc_dep1;
249          UInt zf   = res == 0;
250          return zf;
251       }
252       case ARMG_CC_OP_MULL: {
253          /* (resLo32, resHi32, oldC:oldV) */
254          UInt resLo32 = cc_dep1;
255          UInt resHi32 = cc_dep2;
256          UInt zf      = (resHi32|resLo32) == 0;
257          return zf;
258       }
259       default:
260          /* shouldn't really make these calls from generated code */
261          vex_printf("armg_calculate_flags_z"
262                     "( op=%u, dep1=0x%x, dep2=0x%x, dep3=0x%x )\n",
263                     cc_op, cc_dep1, cc_dep2, cc_dep3 );
264          vpanic("armg_calculate_flags_z");
265    }
266 }
267 
268 
269 /* CALLED FROM GENERATED CODE: CLEAN HELPER */
270 /* Calculate the C flag from the supplied thunk components, in the
271    least significant bit of the word.  Returned bits 31:1 are zero. */
armg_calculate_flag_c(UInt cc_op,UInt cc_dep1,UInt cc_dep2,UInt cc_dep3)272 UInt armg_calculate_flag_c ( UInt cc_op, UInt cc_dep1,
273                              UInt cc_dep2, UInt cc_dep3 )
274 {
275 #  if PROFILE_NZCV_FLAGS
276    NOTE_C_EVAL(cc_op);
277 #  endif
278 
279    switch (cc_op) {
280       case ARMG_CC_OP_COPY: {
281          /* (nzcv:28x0, unused, unused) */
282          UInt cf   = (cc_dep1 >> ARMG_CC_SHIFT_C) & 1;
283          return cf;
284       }
285       case ARMG_CC_OP_ADD: {
286          /* (argL, argR, unused) */
287          UInt argL = cc_dep1;
288          UInt argR = cc_dep2;
289          UInt res  = argL + argR;
290          UInt cf   = res < argL;
291          return cf;
292       }
293       case ARMG_CC_OP_SUB: {
294          /* (argL, argR, unused) */
295          UInt argL = cc_dep1;
296          UInt argR = cc_dep2;
297          UInt cf   = argL >= argR;
298          return cf;
299       }
300       case ARMG_CC_OP_ADC: {
301          /* (argL, argR, oldC) */
302          UInt argL = cc_dep1;
303          UInt argR = cc_dep2;
304          UInt oldC = cc_dep3;
305          vassert((oldC & ~1) == 0);
306          UInt res  = argL + argR + oldC;
307          UInt cf   = oldC ? (res <= argL) : (res < argL);
308          return cf;
309       }
310       case ARMG_CC_OP_SBB: {
311          /* (argL, argR, oldC) */
312          UInt argL = cc_dep1;
313          UInt argR = cc_dep2;
314          UInt oldC = cc_dep3;
315          vassert((oldC & ~1) == 0);
316          UInt cf   = oldC ? (argL >= argR) : (argL > argR);
317          return cf;
318       }
319       case ARMG_CC_OP_LOGIC: {
320          /* (res, shco, oldV) */
321          UInt shco = cc_dep2;
322          vassert((shco & ~1) == 0);
323          UInt cf   = shco;
324          return cf;
325       }
326       case ARMG_CC_OP_MUL: {
327          /* (res, unused, oldC:oldV) */
328          UInt oldC = (cc_dep3 >> 1) & 1;
329          vassert((cc_dep3 & ~3) == 0);
330          UInt cf   = oldC;
331          return cf;
332       }
333       case ARMG_CC_OP_MULL: {
334          /* (resLo32, resHi32, oldC:oldV) */
335          UInt oldC    = (cc_dep3 >> 1) & 1;
336          vassert((cc_dep3 & ~3) == 0);
337          UInt cf      = oldC;
338          return cf;
339       }
340       default:
341          /* shouldn't really make these calls from generated code */
342          vex_printf("armg_calculate_flag_c"
343                     "( op=%u, dep1=0x%x, dep2=0x%x, dep3=0x%x )\n",
344                     cc_op, cc_dep1, cc_dep2, cc_dep3 );
345          vpanic("armg_calculate_flag_c");
346    }
347 }
348 
349 
350 /* CALLED FROM GENERATED CODE: CLEAN HELPER */
351 /* Calculate the V flag from the supplied thunk components, in the
352    least significant bit of the word.  Returned bits 31:1 are zero. */
armg_calculate_flag_v(UInt cc_op,UInt cc_dep1,UInt cc_dep2,UInt cc_dep3)353 UInt armg_calculate_flag_v ( UInt cc_op, UInt cc_dep1,
354                              UInt cc_dep2, UInt cc_dep3 )
355 {
356 #  if PROFILE_NZCV_FLAGS
357    NOTE_V_EVAL(cc_op);
358 #  endif
359 
360    switch (cc_op) {
361       case ARMG_CC_OP_COPY: {
362          /* (nzcv:28x0, unused, unused) */
363          UInt vf   = (cc_dep1 >> ARMG_CC_SHIFT_V) & 1;
364          return vf;
365       }
366       case ARMG_CC_OP_ADD: {
367          /* (argL, argR, unused) */
368          UInt argL = cc_dep1;
369          UInt argR = cc_dep2;
370          UInt res  = argL + argR;
371          UInt vf   = ((res ^ argL) & (res ^ argR)) >> 31;
372          return vf;
373       }
374       case ARMG_CC_OP_SUB: {
375          /* (argL, argR, unused) */
376          UInt argL = cc_dep1;
377          UInt argR = cc_dep2;
378          UInt res  = argL - argR;
379          UInt vf   = ((argL ^ argR) & (argL ^ res)) >> 31;
380          return vf;
381       }
382       case ARMG_CC_OP_ADC: {
383          /* (argL, argR, oldC) */
384          UInt argL = cc_dep1;
385          UInt argR = cc_dep2;
386          UInt oldC = cc_dep3;
387          vassert((oldC & ~1) == 0);
388          UInt res  = argL + argR + oldC;
389          UInt vf   = ((res ^ argL) & (res ^ argR)) >> 31;
390          return vf;
391       }
392       case ARMG_CC_OP_SBB: {
393          /* (argL, argR, oldC) */
394          UInt argL = cc_dep1;
395          UInt argR = cc_dep2;
396          UInt oldC = cc_dep3;
397          vassert((oldC & ~1) == 0);
398          UInt res  = argL - argR - (oldC ^ 1);
399          UInt vf   = ((argL ^ argR) & (argL ^ res)) >> 31;
400          return vf;
401       }
402       case ARMG_CC_OP_LOGIC: {
403          /* (res, shco, oldV) */
404          UInt oldV = cc_dep3;
405          vassert((oldV & ~1) == 0);
406          UInt vf   = oldV;
407          return vf;
408       }
409       case ARMG_CC_OP_MUL: {
410          /* (res, unused, oldC:oldV) */
411          UInt oldV = (cc_dep3 >> 0) & 1;
412          vassert((cc_dep3 & ~3) == 0);
413          UInt vf   = oldV;
414          return vf;
415       }
416       case ARMG_CC_OP_MULL: {
417          /* (resLo32, resHi32, oldC:oldV) */
418          UInt oldV    = (cc_dep3 >> 0) & 1;
419          vassert((cc_dep3 & ~3) == 0);
420          UInt vf      = oldV;
421          return vf;
422       }
423       default:
424          /* shouldn't really make these calls from generated code */
425          vex_printf("armg_calculate_flag_v"
426                     "( op=%u, dep1=0x%x, dep2=0x%x, dep3=0x%x )\n",
427                     cc_op, cc_dep1, cc_dep2, cc_dep3 );
428          vpanic("armg_calculate_flag_v");
429    }
430 }
431 
432 
433 /* CALLED FROM GENERATED CODE: CLEAN HELPER */
434 /* Calculate NZCV from the supplied thunk components, in the positions
435    they appear in the CPSR, viz bits 31:28 for N Z C V respectively.
436    Returned bits 27:0 are zero. */
armg_calculate_flags_nzcv(UInt cc_op,UInt cc_dep1,UInt cc_dep2,UInt cc_dep3)437 UInt armg_calculate_flags_nzcv ( UInt cc_op, UInt cc_dep1,
438                                  UInt cc_dep2, UInt cc_dep3 )
439 {
440    UInt f;
441    UInt res = 0;
442    f = armg_calculate_flag_n(cc_op, cc_dep1, cc_dep2, cc_dep3);
443    res |= (f << ARMG_CC_SHIFT_N);
444    f = armg_calculate_flag_z(cc_op, cc_dep1, cc_dep2, cc_dep3);
445    res |= (f << ARMG_CC_SHIFT_Z);
446    f = armg_calculate_flag_c(cc_op, cc_dep1, cc_dep2, cc_dep3);
447    res |= (f << ARMG_CC_SHIFT_C);
448    f = armg_calculate_flag_v(cc_op, cc_dep1, cc_dep2, cc_dep3);
449    res |= (f << ARMG_CC_SHIFT_V);
450    return res;
451 }
452 
453 
454 /* CALLED FROM GENERATED CODE: CLEAN HELPER */
455 /* Calculate the QC flag from the arguments, in the lowest bit
456    of the word (bit 0).  Urr, having this out of line is bizarre.
457    Push back inline. */
armg_calculate_flag_qc(UInt resL1,UInt resL2,UInt resR1,UInt resR2)458 UInt armg_calculate_flag_qc ( UInt resL1, UInt resL2,
459                               UInt resR1, UInt resR2 )
460 {
461    if (resL1 != resR1 || resL2 != resR2)
462       return 1;
463    else
464       return 0;
465 }
466 
467 /* CALLED FROM GENERATED CODE: CLEAN HELPER */
468 /* Calculate the specified condition from the thunk components, in the
469    lowest bit of the word (bit 0).  Returned bits 31:1 are zero. */
armg_calculate_condition(UInt cond_n_op,UInt cc_dep1,UInt cc_dep2,UInt cc_dep3)470 UInt armg_calculate_condition ( UInt cond_n_op /* (ARMCondcode << 4) | cc_op */,
471                                 UInt cc_dep1,
472                                 UInt cc_dep2, UInt cc_dep3 )
473 {
474    UInt cond  = cond_n_op >> 4;
475    UInt cc_op = cond_n_op & 0xF;
476    UInt nf, zf, vf, cf, inv;
477    //   vex_printf("XXXXXXXX %x %x %x %x\n",
478    //              cond_n_op, cc_dep1, cc_dep2, cc_dep3);
479 
480    // skip flags computation in this case
481    if (cond == ARMCondAL) return 1;
482 
483    inv  = cond & 1;
484 
485    switch (cond) {
486       case ARMCondEQ:    // Z=1         => z
487       case ARMCondNE:    // Z=0
488          zf = armg_calculate_flag_z(cc_op, cc_dep1, cc_dep2, cc_dep3);
489          return inv ^ zf;
490 
491       case ARMCondHS:    // C=1         => c
492       case ARMCondLO:    // C=0
493          cf = armg_calculate_flag_c(cc_op, cc_dep1, cc_dep2, cc_dep3);
494          return inv ^ cf;
495 
496       case ARMCondMI:    // N=1         => n
497       case ARMCondPL:    // N=0
498          nf = armg_calculate_flag_n(cc_op, cc_dep1, cc_dep2, cc_dep3);
499          return inv ^ nf;
500 
501       case ARMCondVS:    // V=1         => v
502       case ARMCondVC:    // V=0
503          vf = armg_calculate_flag_v(cc_op, cc_dep1, cc_dep2, cc_dep3);
504          return inv ^ vf;
505 
506       case ARMCondHI:    // C=1 && Z=0   => c & ~z
507       case ARMCondLS:    // C=0 || Z=1
508          cf = armg_calculate_flag_c(cc_op, cc_dep1, cc_dep2, cc_dep3);
509          zf = armg_calculate_flag_z(cc_op, cc_dep1, cc_dep2, cc_dep3);
510          return inv ^ (1 & (cf & ~zf));
511 
512       case ARMCondGE:    // N=V          => ~(n^v)
513       case ARMCondLT:    // N!=V
514          nf = armg_calculate_flag_n(cc_op, cc_dep1, cc_dep2, cc_dep3);
515          vf = armg_calculate_flag_v(cc_op, cc_dep1, cc_dep2, cc_dep3);
516          return inv ^ (1 & ~(nf ^ vf));
517 
518       case ARMCondGT:    // Z=0 && N=V   => ~z & ~(n^v)  =>  ~(z | (n^v))
519       case ARMCondLE:    // Z=1 || N!=V
520          nf = armg_calculate_flag_n(cc_op, cc_dep1, cc_dep2, cc_dep3);
521          vf = armg_calculate_flag_v(cc_op, cc_dep1, cc_dep2, cc_dep3);
522          zf = armg_calculate_flag_z(cc_op, cc_dep1, cc_dep2, cc_dep3);
523          return inv ^ (1 & ~(zf | (nf ^ vf)));
524 
525       case ARMCondAL: // handled above
526       case ARMCondNV: // should never get here: Illegal instr
527       default:
528          /* shouldn't really make these calls from generated code */
529          vex_printf("armg_calculate_condition(ARM)"
530                     "( %u, %u, 0x%x, 0x%x, 0x%x )\n",
531                     cond, cc_op, cc_dep1, cc_dep2, cc_dep3 );
532          vpanic("armg_calculate_condition(ARM)");
533    }
534 }
535 
536 
537 /*---------------------------------------------------------------*/
538 /*--- Flag-helpers translation-time function specialisers.    ---*/
539 /*--- These help iropt specialise calls the above run-time    ---*/
540 /*--- flags functions.                                        ---*/
541 /*---------------------------------------------------------------*/
542 
543 /* Used by the optimiser to try specialisations.  Returns an
544    equivalent expression, or NULL if none. */
545 
isU32(IRExpr * e,UInt n)546 static Bool isU32 ( IRExpr* e, UInt n )
547 {
548    return
549       toBool( e->tag == Iex_Const
550               && e->Iex.Const.con->tag == Ico_U32
551               && e->Iex.Const.con->Ico.U32 == n );
552 }
553 
guest_arm_spechelper(const HChar * function_name,IRExpr ** args,IRStmt ** precedingStmts,Int n_precedingStmts)554 IRExpr* guest_arm_spechelper ( const HChar* function_name,
555                                IRExpr** args,
556                                IRStmt** precedingStmts,
557                                Int      n_precedingStmts )
558 {
559 #  define unop(_op,_a1) IRExpr_Unop((_op),(_a1))
560 #  define binop(_op,_a1,_a2) IRExpr_Binop((_op),(_a1),(_a2))
561 #  define mkU32(_n) IRExpr_Const(IRConst_U32(_n))
562 #  define mkU8(_n)  IRExpr_Const(IRConst_U8(_n))
563 
564    Int i, arity = 0;
565    for (i = 0; args[i]; i++)
566       arity++;
567 #  if 0
568    vex_printf("spec request:\n");
569    vex_printf("   %s  ", function_name);
570    for (i = 0; i < arity; i++) {
571       vex_printf("  ");
572       ppIRExpr(args[i]);
573    }
574    vex_printf("\n");
575 #  endif
576 
577    /* --------- specialising "armg_calculate_condition" --------- */
578 
579    if (vex_streq(function_name, "armg_calculate_condition")) {
580 
581       /* specialise calls to the "armg_calculate_condition" function.
582          Not sure whether this is strictly necessary, but: the
583          replacement IR must produce only the values 0 or 1.  Bits
584          31:1 are required to be zero. */
585       IRExpr *cond_n_op, *cc_dep1, *cc_dep2, *cc_ndep;
586       vassert(arity == 4);
587       cond_n_op = args[0]; /* (ARMCondcode << 4)  |  ARMG_CC_OP_* */
588       cc_dep1   = args[1];
589       cc_dep2   = args[2];
590       cc_ndep   = args[3];
591 
592       /*---------------- SUB ----------------*/
593 
594       if (isU32(cond_n_op, (ARMCondEQ << 4) | ARMG_CC_OP_SUB)) {
595          /* EQ after SUB --> test argL == argR */
596          return unop(Iop_1Uto32,
597                      binop(Iop_CmpEQ32, cc_dep1, cc_dep2));
598       }
599       if (isU32(cond_n_op, (ARMCondNE << 4) | ARMG_CC_OP_SUB)) {
600          /* NE after SUB --> test argL != argR */
601          return unop(Iop_1Uto32,
602                      binop(Iop_CmpNE32, cc_dep1, cc_dep2));
603       }
604 
605       if (isU32(cond_n_op, (ARMCondGT << 4) | ARMG_CC_OP_SUB)) {
606          /* GT after SUB --> test argL >s argR
607                          --> test argR <s argL */
608          return unop(Iop_1Uto32,
609                      binop(Iop_CmpLT32S, cc_dep2, cc_dep1));
610       }
611       if (isU32(cond_n_op, (ARMCondLE << 4) | ARMG_CC_OP_SUB)) {
612          /* LE after SUB --> test argL <=s argR */
613          return unop(Iop_1Uto32,
614                      binop(Iop_CmpLE32S, cc_dep1, cc_dep2));
615       }
616 
617       if (isU32(cond_n_op, (ARMCondLT << 4) | ARMG_CC_OP_SUB)) {
618          /* LT after SUB --> test argL <s argR */
619          return unop(Iop_1Uto32,
620                      binop(Iop_CmpLT32S, cc_dep1, cc_dep2));
621       }
622 
623       if (isU32(cond_n_op, (ARMCondGE << 4) | ARMG_CC_OP_SUB)) {
624          /* GE after SUB --> test argL >=s argR
625                          --> test argR <=s argL */
626          return unop(Iop_1Uto32,
627                      binop(Iop_CmpLE32S, cc_dep2, cc_dep1));
628       }
629 
630       if (isU32(cond_n_op, (ARMCondHS << 4) | ARMG_CC_OP_SUB)) {
631          /* HS after SUB --> test argL >=u argR
632                          --> test argR <=u argL */
633          return unop(Iop_1Uto32,
634                      binop(Iop_CmpLE32U, cc_dep2, cc_dep1));
635       }
636       if (isU32(cond_n_op, (ARMCondLO << 4) | ARMG_CC_OP_SUB)) {
637          /* LO after SUB --> test argL <u argR */
638          return unop(Iop_1Uto32,
639                      binop(Iop_CmpLT32U, cc_dep1, cc_dep2));
640       }
641 
642       if (isU32(cond_n_op, (ARMCondLS << 4) | ARMG_CC_OP_SUB)) {
643          /* LS after SUB --> test argL <=u argR */
644          return unop(Iop_1Uto32,
645                      binop(Iop_CmpLE32U, cc_dep1, cc_dep2));
646       }
647       if (isU32(cond_n_op, (ARMCondHI << 4) | ARMG_CC_OP_SUB)) {
648          /* HI after SUB --> test argL >u argR
649                          --> test argR <u argL */
650          return unop(Iop_1Uto32,
651                      binop(Iop_CmpLT32U, cc_dep2, cc_dep1));
652       }
653 
654       /*---------------- SBB ----------------*/
655 
656       if (isU32(cond_n_op, (ARMCondHS << 4) | ARMG_CC_OP_SBB)) {
657          /* This seems to happen a lot in softfloat code, eg __divdf3+140 */
658          /* thunk is: (dep1=argL, dep2=argR, ndep=oldC) */
659          /* HS after SBB (same as C after SBB below)
660             --> oldC ? (argL >=u argR) : (argL >u argR)
661             --> oldC ? (argR <=u argL) : (argR <u argL)
662          */
663          return
664             IRExpr_ITE(
665                binop(Iop_CmpNE32, cc_ndep, mkU32(0)),
666                /* case oldC != 0 */
667                unop(Iop_1Uto32, binop(Iop_CmpLE32U, cc_dep2, cc_dep1)),
668                /* case oldC == 0 */
669                unop(Iop_1Uto32, binop(Iop_CmpLT32U, cc_dep2, cc_dep1))
670             );
671       }
672 
673       /*---------------- LOGIC ----------------*/
674 
675       if (isU32(cond_n_op, (ARMCondEQ << 4) | ARMG_CC_OP_LOGIC)) {
676          /* EQ after LOGIC --> test res == 0 */
677          return unop(Iop_1Uto32,
678                      binop(Iop_CmpEQ32, cc_dep1, mkU32(0)));
679       }
680       if (isU32(cond_n_op, (ARMCondNE << 4) | ARMG_CC_OP_LOGIC)) {
681          /* NE after LOGIC --> test res != 0 */
682          return unop(Iop_1Uto32,
683                      binop(Iop_CmpNE32, cc_dep1, mkU32(0)));
684       }
685 
686       if (isU32(cond_n_op, (ARMCondPL << 4) | ARMG_CC_OP_LOGIC)) {
687          /* PL after LOGIC --> test (res >> 31) == 0 */
688          return unop(Iop_1Uto32,
689                      binop(Iop_CmpEQ32,
690                            binop(Iop_Shr32, cc_dep1, mkU8(31)),
691                            mkU32(0)));
692       }
693       if (isU32(cond_n_op, (ARMCondMI << 4) | ARMG_CC_OP_LOGIC)) {
694          /* MI after LOGIC --> test (res >> 31) == 1 */
695          return unop(Iop_1Uto32,
696                      binop(Iop_CmpEQ32,
697                            binop(Iop_Shr32, cc_dep1, mkU8(31)),
698                            mkU32(1)));
699       }
700 
701       /*---------------- COPY ----------------*/
702 
703       /* --- 0,1 --- */
704       if (isU32(cond_n_op, (ARMCondEQ << 4) | ARMG_CC_OP_COPY)) {
705          /* EQ after COPY --> (cc_dep1 >> ARMG_CC_SHIFT_Z) & 1 */
706          return binop(Iop_And32,
707                       binop(Iop_Shr32, cc_dep1,
708                             mkU8(ARMG_CC_SHIFT_Z)),
709                       mkU32(1));
710       }
711       if (isU32(cond_n_op, (ARMCondNE << 4) | ARMG_CC_OP_COPY)) {
712          /* NE after COPY --> ((cc_dep1 >> ARMG_CC_SHIFT_Z) ^ 1) & 1 */
713          return binop(Iop_And32,
714                       binop(Iop_Xor32,
715                             binop(Iop_Shr32, cc_dep1,
716                                              mkU8(ARMG_CC_SHIFT_Z)),
717                             mkU32(1)),
718                       mkU32(1));
719       }
720 
721       /* --- 4,5 --- */
722       if (isU32(cond_n_op, (ARMCondMI << 4) | ARMG_CC_OP_COPY)) {
723          /* MI after COPY --> (cc_dep1 >> ARMG_CC_SHIFT_N) & 1 */
724          return binop(Iop_And32,
725                       binop(Iop_Shr32, cc_dep1,
726                             mkU8(ARMG_CC_SHIFT_N)),
727                       mkU32(1));
728       }
729       if (isU32(cond_n_op, (ARMCondPL << 4) | ARMG_CC_OP_COPY)) {
730          /* PL after COPY --> ((cc_dep1 >> ARMG_CC_SHIFT_N) ^ 1) & 1 */
731          return binop(Iop_And32,
732                       binop(Iop_Xor32,
733                             binop(Iop_Shr32, cc_dep1,
734                                              mkU8(ARMG_CC_SHIFT_N)),
735                             mkU32(1)),
736                       mkU32(1));
737       }
738 
739       /* --- 12,13 --- */
740       if (isU32(cond_n_op, (ARMCondGT << 4) | ARMG_CC_OP_COPY)) {
741          /* GT after COPY --> ((z | (n^v)) & 1) ^ 1 */
742          IRExpr* n = binop(Iop_Shr32, cc_dep1, mkU8(ARMG_CC_SHIFT_N));
743          IRExpr* v = binop(Iop_Shr32, cc_dep1, mkU8(ARMG_CC_SHIFT_V));
744          IRExpr* z = binop(Iop_Shr32, cc_dep1, mkU8(ARMG_CC_SHIFT_Z));
745          return binop(Iop_Xor32,
746                       binop(Iop_And32,
747                             binop(Iop_Or32, z, binop(Iop_Xor32, n, v)),
748                             mkU32(1)),
749                       mkU32(1));
750       }
751       if (isU32(cond_n_op, (ARMCondLE << 4) | ARMG_CC_OP_COPY)) {
752          /* LE after COPY --> ((z | (n^v)) & 1) ^ 0 */
753          IRExpr* n = binop(Iop_Shr32, cc_dep1, mkU8(ARMG_CC_SHIFT_N));
754          IRExpr* v = binop(Iop_Shr32, cc_dep1, mkU8(ARMG_CC_SHIFT_V));
755          IRExpr* z = binop(Iop_Shr32, cc_dep1, mkU8(ARMG_CC_SHIFT_Z));
756          return binop(Iop_Xor32,
757                       binop(Iop_And32,
758                             binop(Iop_Or32, z, binop(Iop_Xor32, n, v)),
759                             mkU32(1)),
760                       mkU32(0));
761       }
762 
763       /*----------------- AL -----------------*/
764 
765       /* A critically important case for Thumb code.
766 
767          What we're trying to spot is the case where cond_n_op is an
768          expression of the form Or32(..., 0xE0) since that means the
769          caller is asking for CondAL and we can simply return 1
770          without caring what the ... part is.  This is a potentially
771          dodgy kludge in that it assumes that the ... part has zeroes
772          in bits 7:4, so that the result of the Or32 is guaranteed to
773          be 0xE in bits 7:4.  Given that the places where this first
774          arg are constructed (in guest_arm_toIR.c) are very
775          constrained, we can get away with this.  To make this
776          guaranteed safe would require to have a new primop, Slice44
777          or some such, thusly
778 
779          Slice44(arg1, arg2) = 0--(24)--0 arg1[7:4] arg2[3:0]
780 
781          and we would then look for Slice44(0xE0, ...)
782          which would give the required safety property.
783 
784          It would be infeasibly expensive to scan backwards through
785          the entire block looking for an assignment to the temp, so
786          just look at the previous 16 statements.  That should find it
787          if it is an interesting case, as a result of how the
788          boilerplate guff at the start of each Thumb insn translation
789          is made.
790       */
791       if (cond_n_op->tag == Iex_RdTmp) {
792          Int    j;
793          IRTemp look_for = cond_n_op->Iex.RdTmp.tmp;
794          Int    limit    = n_precedingStmts - 16;
795          if (limit < 0) limit = 0;
796          if (0) vex_printf("scanning %d .. %d\n", n_precedingStmts-1, limit);
797          for (j = n_precedingStmts - 1; j >= limit; j--) {
798             IRStmt* st = precedingStmts[j];
799             if (st->tag == Ist_WrTmp
800                 && st->Ist.WrTmp.tmp == look_for
801                 && st->Ist.WrTmp.data->tag == Iex_Binop
802                 && st->Ist.WrTmp.data->Iex.Binop.op == Iop_Or32
803                 && isU32(st->Ist.WrTmp.data->Iex.Binop.arg2, (ARMCondAL << 4)))
804                return mkU32(1);
805          }
806          /* Didn't find any useful binding to the first arg
807             in the previous 16 stmts. */
808       }
809    }
810 
811    /* --------- specialising "armg_calculate_flag_c" --------- */
812 
813    else
814    if (vex_streq(function_name, "armg_calculate_flag_c")) {
815 
816       /* specialise calls to the "armg_calculate_flag_c" function.
817          Note that the returned value must be either 0 or 1; nonzero
818          bits 31:1 are not allowed.  In turn, incoming oldV and oldC
819          values (from the thunk) are assumed to have bits 31:1
820          clear. */
821       IRExpr *cc_op, *cc_dep1, *cc_dep2, *cc_ndep;
822       vassert(arity == 4);
823       cc_op   = args[0]; /* ARMG_CC_OP_* */
824       cc_dep1 = args[1];
825       cc_dep2 = args[2];
826       cc_ndep = args[3];
827 
828       if (isU32(cc_op, ARMG_CC_OP_LOGIC)) {
829          /* Thunk args are (result, shco, oldV) */
830          /* C after LOGIC --> shco */
831          return cc_dep2;
832       }
833 
834       if (isU32(cc_op, ARMG_CC_OP_SUB)) {
835          /* Thunk args are (argL, argR, unused) */
836          /* C after SUB --> argL >=u argR
837                         --> argR <=u argL */
838          return unop(Iop_1Uto32,
839                      binop(Iop_CmpLE32U, cc_dep2, cc_dep1));
840       }
841 
842       if (isU32(cc_op, ARMG_CC_OP_SBB)) {
843          /* This happens occasionally in softfloat code, eg __divdf3+140 */
844          /* thunk is: (dep1=argL, dep2=argR, ndep=oldC) */
845          /* C after SBB (same as HS after SBB above)
846             --> oldC ? (argL >=u argR) : (argL >u argR)
847             --> oldC ? (argR <=u argL) : (argR <u argL)
848          */
849          return
850             IRExpr_ITE(
851                binop(Iop_CmpNE32, cc_ndep, mkU32(0)),
852                /* case oldC != 0 */
853                unop(Iop_1Uto32, binop(Iop_CmpLE32U, cc_dep2, cc_dep1)),
854                /* case oldC == 0 */
855                unop(Iop_1Uto32, binop(Iop_CmpLT32U, cc_dep2, cc_dep1))
856             );
857       }
858 
859    }
860 
861    /* --------- specialising "armg_calculate_flag_v" --------- */
862 
863    else
864    if (vex_streq(function_name, "armg_calculate_flag_v")) {
865 
866       /* specialise calls to the "armg_calculate_flag_v" function.
867          Note that the returned value must be either 0 or 1; nonzero
868          bits 31:1 are not allowed.  In turn, incoming oldV and oldC
869          values (from the thunk) are assumed to have bits 31:1
870          clear. */
871       IRExpr *cc_op, *cc_dep1, *cc_dep2, *cc_ndep;
872       vassert(arity == 4);
873       cc_op   = args[0]; /* ARMG_CC_OP_* */
874       cc_dep1 = args[1];
875       cc_dep2 = args[2];
876       cc_ndep = args[3];
877 
878       if (isU32(cc_op, ARMG_CC_OP_LOGIC)) {
879          /* Thunk args are (result, shco, oldV) */
880          /* V after LOGIC --> oldV */
881          return cc_ndep;
882       }
883 
884       if (isU32(cc_op, ARMG_CC_OP_SUB)) {
885          /* Thunk args are (argL, argR, unused) */
886          /* V after SUB
887             --> let res = argL - argR
888                 in ((argL ^ argR) & (argL ^ res)) >> 31
889             --> ((argL ^ argR) & (argL ^ (argL - argR))) >> 31
890          */
891          IRExpr* argL = cc_dep1;
892          IRExpr* argR = cc_dep2;
893          return
894             binop(Iop_Shr32,
895                   binop(Iop_And32,
896                         binop(Iop_Xor32, argL, argR),
897                         binop(Iop_Xor32, argL, binop(Iop_Sub32, argL, argR))
898                   ),
899                   mkU8(31)
900             );
901       }
902 
903       if (isU32(cc_op, ARMG_CC_OP_SBB)) {
904          /* This happens occasionally in softfloat code, eg __divdf3+140 */
905          /* thunk is: (dep1=argL, dep2=argR, ndep=oldC) */
906          /* V after SBB
907             --> let res = argL - argR - (oldC ^ 1)
908                 in  (argL ^ argR) & (argL ^ res) & 1
909          */
910          return
911             binop(
912                Iop_And32,
913                binop(
914                   Iop_And32,
915                   // argL ^ argR
916                   binop(Iop_Xor32, cc_dep1, cc_dep2),
917                   // argL ^ (argL - argR - (oldC ^ 1))
918                   binop(Iop_Xor32,
919                         cc_dep1,
920                         binop(Iop_Sub32,
921                               binop(Iop_Sub32, cc_dep1, cc_dep2),
922                               binop(Iop_Xor32, cc_ndep, mkU32(1)))
923                   )
924                ),
925                mkU32(1)
926             );
927       }
928 
929    }
930 
931 #  undef unop
932 #  undef binop
933 #  undef mkU32
934 #  undef mkU8
935 
936    return NULL;
937 }
938 
939 
940 /*----------------------------------------------*/
941 /*--- The exported fns ..                    ---*/
942 /*----------------------------------------------*/
943 
944 /* VISIBLE TO LIBVEX CLIENT */
945 #if 0
946 void LibVEX_GuestARM_put_flags ( UInt flags_native,
947                                  /*OUT*/VexGuestARMState* vex_state )
948 {
949    vassert(0); // FIXME
950 
951    /* Mask out everything except N Z V C. */
952    flags_native
953       &= (ARMG_CC_MASK_N | ARMG_CC_MASK_Z | ARMG_CC_MASK_V | ARMG_CC_MASK_C);
954 
955    vex_state->guest_CC_OP   = ARMG_CC_OP_COPY;
956    vex_state->guest_CC_DEP1 = flags_native;
957    vex_state->guest_CC_DEP2 = 0;
958    vex_state->guest_CC_NDEP = 0;
959 }
960 #endif
961 
962 /* VISIBLE TO LIBVEX CLIENT */
LibVEX_GuestARM_get_cpsr(const VexGuestARMState * vex_state)963 UInt LibVEX_GuestARM_get_cpsr ( /*IN*/const VexGuestARMState* vex_state )
964 {
965    UInt cpsr = 0;
966    // NZCV
967    cpsr |= armg_calculate_flags_nzcv(
968                vex_state->guest_CC_OP,
969                vex_state->guest_CC_DEP1,
970                vex_state->guest_CC_DEP2,
971                vex_state->guest_CC_NDEP
972             );
973    vassert(0 == (cpsr & 0x0FFFFFFF));
974    // Q
975    if (vex_state->guest_QFLAG32 > 0)
976       cpsr |= (1 << 27);
977    // GE
978    if (vex_state->guest_GEFLAG0 > 0)
979       cpsr |= (1 << 16);
980    if (vex_state->guest_GEFLAG1 > 0)
981       cpsr |= (1 << 17);
982    if (vex_state->guest_GEFLAG2 > 0)
983       cpsr |= (1 << 18);
984    if (vex_state->guest_GEFLAG3 > 0)
985       cpsr |= (1 << 19);
986    // M
987    cpsr |= (1 << 4); // 0b10000 means user-mode
988    // J,T   J (bit 24) is zero by initialisation above
989    // T  we copy from R15T[0]
990    if (vex_state->guest_R15T & 1)
991       cpsr |= (1 << 5);
992    // ITSTATE we punt on for the time being.  Could compute it
993    // if needed though.
994    // E, endianness, 0 (littleendian) from initialisation above
995    // A,I,F disable some async exceptions.  Not sure about these.
996    // Leave as zero for the time being.
997    return cpsr;
998 }
999 
1000 /* VISIBLE TO LIBVEX CLIENT */
LibVEX_GuestARM_initialise(VexGuestARMState * vex_state)1001 void LibVEX_GuestARM_initialise ( /*OUT*/VexGuestARMState* vex_state )
1002 {
1003    vex_state->host_EvC_FAILADDR = 0;
1004    vex_state->host_EvC_COUNTER = 0;
1005 
1006    vex_state->guest_R0  = 0;
1007    vex_state->guest_R1  = 0;
1008    vex_state->guest_R2  = 0;
1009    vex_state->guest_R3  = 0;
1010    vex_state->guest_R4  = 0;
1011    vex_state->guest_R5  = 0;
1012    vex_state->guest_R6  = 0;
1013    vex_state->guest_R7  = 0;
1014    vex_state->guest_R8  = 0;
1015    vex_state->guest_R9  = 0;
1016    vex_state->guest_R10 = 0;
1017    vex_state->guest_R11 = 0;
1018    vex_state->guest_R12 = 0;
1019    vex_state->guest_R13 = 0;
1020    vex_state->guest_R14 = 0;
1021    vex_state->guest_R15T = 0;  /* NB: implies ARM mode */
1022 
1023    vex_state->guest_CC_OP   = ARMG_CC_OP_COPY;
1024    vex_state->guest_CC_DEP1 = 0;
1025    vex_state->guest_CC_DEP2 = 0;
1026    vex_state->guest_CC_NDEP = 0;
1027    vex_state->guest_QFLAG32 = 0;
1028    vex_state->guest_GEFLAG0 = 0;
1029    vex_state->guest_GEFLAG1 = 0;
1030    vex_state->guest_GEFLAG2 = 0;
1031    vex_state->guest_GEFLAG3 = 0;
1032 
1033    vex_state->guest_EMNOTE  = EmNote_NONE;
1034    vex_state->guest_CMSTART = 0;
1035    vex_state->guest_CMLEN   = 0;
1036    vex_state->guest_NRADDR  = 0;
1037    vex_state->guest_IP_AT_SYSCALL = 0;
1038 
1039    vex_state->guest_D0  = 0;
1040    vex_state->guest_D1  = 0;
1041    vex_state->guest_D2  = 0;
1042    vex_state->guest_D3  = 0;
1043    vex_state->guest_D4  = 0;
1044    vex_state->guest_D5  = 0;
1045    vex_state->guest_D6  = 0;
1046    vex_state->guest_D7  = 0;
1047    vex_state->guest_D8  = 0;
1048    vex_state->guest_D9  = 0;
1049    vex_state->guest_D10 = 0;
1050    vex_state->guest_D11 = 0;
1051    vex_state->guest_D12 = 0;
1052    vex_state->guest_D13 = 0;
1053    vex_state->guest_D14 = 0;
1054    vex_state->guest_D15 = 0;
1055    vex_state->guest_D16 = 0;
1056    vex_state->guest_D17 = 0;
1057    vex_state->guest_D18 = 0;
1058    vex_state->guest_D19 = 0;
1059    vex_state->guest_D20 = 0;
1060    vex_state->guest_D21 = 0;
1061    vex_state->guest_D22 = 0;
1062    vex_state->guest_D23 = 0;
1063    vex_state->guest_D24 = 0;
1064    vex_state->guest_D25 = 0;
1065    vex_state->guest_D26 = 0;
1066    vex_state->guest_D27 = 0;
1067    vex_state->guest_D28 = 0;
1068    vex_state->guest_D29 = 0;
1069    vex_state->guest_D30 = 0;
1070    vex_state->guest_D31 = 0;
1071 
1072    /* ARM encoded; zero is the default as it happens (result flags
1073       (NZCV) cleared, FZ disabled, round to nearest, non-vector mode,
1074       all exns masked, all exn sticky bits cleared). */
1075    vex_state->guest_FPSCR = 0;
1076 
1077    vex_state->guest_TPIDRURO = 0;
1078 
1079    /* Not in a Thumb IT block. */
1080    vex_state->guest_ITSTATE = 0;
1081 
1082    vex_state->padding1 = 0;
1083 }
1084 
1085 
1086 /*-----------------------------------------------------------*/
1087 /*--- Describing the arm guest state, for the benefit     ---*/
1088 /*--- of iropt and instrumenters.                         ---*/
1089 /*-----------------------------------------------------------*/
1090 
1091 /* Figure out if any part of the guest state contained in minoff
1092    .. maxoff requires precise memory exceptions.  If in doubt return
1093    True (but this generates significantly slower code).
1094 
1095    We enforce precise exns for guest R13(sp), R15T(pc), R7, R11.
1096 
1097 
1098    Only R13(sp) is needed in mode VexRegUpdSpAtMemAccess.
1099 */
guest_arm_state_requires_precise_mem_exns(Int minoff,Int maxoff,VexRegisterUpdates pxControl)1100 Bool guest_arm_state_requires_precise_mem_exns (
1101         Int minoff, Int maxoff, VexRegisterUpdates pxControl
1102      )
1103 {
1104    Int sp_min = offsetof(VexGuestARMState, guest_R13);
1105    Int sp_max = sp_min + 4 - 1;
1106    Int pc_min = offsetof(VexGuestARMState, guest_R15T);
1107    Int pc_max = pc_min + 4 - 1;
1108 
1109    if (maxoff < sp_min || minoff > sp_max) {
1110       /* no overlap with sp */
1111       if (pxControl == VexRegUpdSpAtMemAccess)
1112          return False; // We only need to check stack pointer.
1113    } else {
1114       return True;
1115    }
1116 
1117    if (maxoff < pc_min || minoff > pc_max) {
1118       /* no overlap with pc */
1119    } else {
1120       return True;
1121    }
1122 
1123    /* We appear to need precise updates of R11 in order to get proper
1124       stacktraces from non-optimised code. */
1125    Int r11_min = offsetof(VexGuestARMState, guest_R11);
1126    Int r11_max = r11_min + 4 - 1;
1127 
1128    if (maxoff < r11_min || minoff > r11_max) {
1129       /* no overlap with r11 */
1130    } else {
1131       return True;
1132    }
1133 
1134    /* Ditto R7, particularly needed for proper stacktraces in Thumb
1135       code. */
1136    Int r7_min = offsetof(VexGuestARMState, guest_R7);
1137    Int r7_max = r7_min + 4 - 1;
1138 
1139    if (maxoff < r7_min || minoff > r7_max) {
1140       /* no overlap with r7 */
1141    } else {
1142       return True;
1143    }
1144 
1145    return False;
1146 }
1147 
1148 
1149 
1150 #define ALWAYSDEFD(field)                           \
1151     { offsetof(VexGuestARMState, field),            \
1152       (sizeof ((VexGuestARMState*)0)->field) }
1153 
1154 VexGuestLayout
1155    armGuest_layout
1156       = {
1157           /* Total size of the guest state, in bytes. */
1158           .total_sizeB = sizeof(VexGuestARMState),
1159 
1160           /* Describe the stack pointer. */
1161           .offset_SP = offsetof(VexGuestARMState,guest_R13),
1162           .sizeof_SP = 4,
1163 
1164           /* Describe the instruction pointer. */
1165           .offset_IP = offsetof(VexGuestARMState,guest_R15T),
1166           .sizeof_IP = 4,
1167 
1168           /* Describe any sections to be regarded by Memcheck as
1169              'always-defined'. */
1170           .n_alwaysDefd = 10,
1171 
1172           /* flags thunk: OP is always defd, whereas DEP1 and DEP2
1173              have to be tracked.  See detailed comment in gdefs.h on
1174              meaning of thunk fields. */
1175           .alwaysDefd
1176              = { /* 0 */ ALWAYSDEFD(guest_R15T),
1177                  /* 1 */ ALWAYSDEFD(guest_CC_OP),
1178                  /* 2 */ ALWAYSDEFD(guest_CC_NDEP),
1179                  /* 3 */ ALWAYSDEFD(guest_EMNOTE),
1180                  /* 4 */ ALWAYSDEFD(guest_CMSTART),
1181                  /* 5 */ ALWAYSDEFD(guest_CMLEN),
1182                  /* 6 */ ALWAYSDEFD(guest_NRADDR),
1183                  /* 7 */ ALWAYSDEFD(guest_IP_AT_SYSCALL),
1184                  /* 8 */ ALWAYSDEFD(guest_TPIDRURO),
1185                  /* 9 */ ALWAYSDEFD(guest_ITSTATE)
1186                }
1187         };
1188 
1189 
1190 /*---------------------------------------------------------------*/
1191 /*--- end                                 guest_arm_helpers.c ---*/
1192 /*---------------------------------------------------------------*/
1193