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8023038: PPC64 (part 15): Platform files for AIX/PPC64 support Reviewed-by: kvn
author simonis
date Fri, 06 Sep 2013 20:16:09 +0200
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14414:b83f7d608548 14415:666e6ce3976c
1 /*
2 * Copyright 2012, 2013 SAP AG. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "asm/assembler.hpp"
26 #include "loadlib_aix.hpp"
27 #include "porting_aix.hpp"
28 #include "utilities/debug.hpp"
29
30 #include <demangle.h>
31 #include <sys/debug.h>
32
33 //////////////////////////////////
34 // Provide implementation for dladdr based on LoadedLibraries pool and
35 // traceback table scan (see getFuncName).
36
37 // Search traceback table in stack,
38 // return procedure name from trace back table.
39 #define MAX_FUNC_SEARCH_LEN 0x10000
40 // Any PC below this value is considered toast.
41 #define MINIMUM_VALUE_FOR_PC ((unsigned int*)0x1024)
42
43 #define PTRDIFF_BYTES(p1,p2) (((ptrdiff_t)p1) - ((ptrdiff_t)p2))
44
45 // Align a pointer without having to cast.
46 inline char* align_ptr_up(char* ptr, intptr_t alignment) {
47 return (char*) align_size_up((intptr_t)ptr, alignment);
48 }
49
50 // Trace if verbose to tty.
51 // I use these now instead of the Xtrace system because the latter is
52 // not available at init time, hence worthless. Until we fix this, all
53 // tracing here is done with -XX:+Verbose.
54 #define trcVerbose(fmt, ...) { \
55 if (Verbose) { \
56 fprintf(stderr, fmt, ##__VA_ARGS__); \
57 fputc('\n', stderr); fflush(stderr); \
58 } \
59 }
60 #define ERRBYE(s) { trcVerbose(s); return -1; }
61
62 // Unfortunately, the interface of dladdr makes the implementator
63 // responsible for maintaining memory for function name/library
64 // name. I guess this is because most OS's keep those values as part
65 // of the mapped executable image ready to use. On AIX, this doesn't
66 // work, so I have to keep the returned strings. For now, I do this in
67 // a primitive string map. Should this turn out to be a performance
68 // problem, a better hashmap has to be used.
69 class fixed_strings {
70 struct node {
71 char* v;
72 node* next;
73 };
74
75 node* first;
76
77 public:
78
79 fixed_strings() : first(0) {}
80 ~fixed_strings() {
81 node* n = first;
82 while (n) {
83 node* p = n;
84 n = n->next;
85 free(p->v);
86 delete p;
87 }
88 }
89
90 char* intern(const char* s) {
91 for (node* n = first; n; n = n->next) {
92 if (strcmp(n->v, s) == 0) {
93 return n->v;
94 }
95 }
96 node* p = new node;
97 p->v = strdup(s);
98 p->next = first;
99 first = p;
100 return p->v;
101 }
102 };
103
104 static fixed_strings dladdr_fixed_strings;
105
106 // Given a code pointer, returns the function name and the displacement.
107 // Function looks for the traceback table at the end of the function.
108 extern "C" int getFuncName(
109 codeptr_t pc, // [in] program counter
110 char* p_name, size_t namelen, // [out] optional: function name ("" if not available)
111 int* p_displacement, // [out] optional: displacement (-1 if not available)
112 const struct tbtable** p_tb, // [out] optional: ptr to traceback table to get further
113 // information (NULL if not available)
114 char* p_errmsg, size_t errmsglen // [out] optional: user provided buffer for error messages
115 ) {
116 struct tbtable* tb = 0;
117 unsigned int searchcount = 0;
118
119 // initialize output parameters
120 if (p_name && namelen > 0) {
121 *p_name = '\0';
122 }
123 if (p_errmsg && errmsglen > 0) {
124 *p_errmsg = '\0';
125 }
126 if (p_displacement) {
127 *p_displacement = -1;
128 }
129 if (p_tb) {
130 *p_tb = NULL;
131 }
132
133 // weed out obvious bogus states
134 if (pc < MINIMUM_VALUE_FOR_PC) {
135 ERRBYE("invalid program counter");
136 }
137
138 codeptr_t pc2 = pc;
139
140 // make sure the pointer is word aligned.
141 pc2 = (codeptr_t) align_ptr_up((char*)pc2, 4);
142
143 // Find start of traceback table.
144 // (starts after code, is marked by word-aligned (32bit) zeros)
145 while ((*pc2 != NULL) && (searchcount++ < MAX_FUNC_SEARCH_LEN)) {
146 pc2++;
147 }
148 if (*pc2 != 0) {
149 ERRBYE("could not find traceback table within 5000 bytes of program counter");
150 }
151 //
152 // Set up addressability to the traceback table
153 //
154 tb = (struct tbtable*) (pc2 + 1);
155
156 // Is this really a traceback table? No way to be sure but
157 // some indicators we can check.
158 if (tb->tb.lang >= 0xf && tb->tb.lang <= 0xfb) {
159 // Language specifiers, go from 0 (C) to 14 (Objective C).
160 // According to spec, 0xf-0xfa reserved, 0xfb-0xff reserved for ibm.
161 ERRBYE("not a traceback table");
162 }
163
164 // Existence of fields in the tbtable extension are contingent upon
165 // specific fields in the base table. Check for their existence so
166 // that we can address the function name if it exists.
167 pc2 = (codeptr_t) tb +
168 sizeof(struct tbtable_short)/sizeof(int);
169 if (tb->tb.fixedparms != 0 || tb->tb.floatparms != 0)
170 pc2++;
171
172 if (tb->tb.has_tboff == TRUE) {
173
174 // I want to know the displacement
175 const unsigned int tb_offset = *pc2;
176 codeptr_t start_of_procedure =
177 (codeptr_t)(((char*)tb) - 4 - tb_offset); // (-4 to omit leading 0000)
178
179 // Weed out the cases where we did find the wrong traceback table.
180 if (pc < start_of_procedure) {
181 ERRBYE("could not find (the real) traceback table within 5000 bytes of program counter");
182 }
183
184 // return the displacement
185 if (p_displacement) {
186 (*p_displacement) = (int) PTRDIFF_BYTES(pc, start_of_procedure);
187 }
188
189 pc2++;
190 } else {
191 // return -1 for displacement
192 if (p_displacement) {
193 (*p_displacement) = -1;
194 }
195 }
196
197 if (tb->tb.int_hndl == TRUE)
198 pc2++;
199
200 if (tb->tb.has_ctl == TRUE)
201 pc2 += (*pc2) + 1; // don't care
202
203 //
204 // return function name if it exists.
205 //
206 if (p_name && namelen > 0) {
207 if (tb->tb.name_present) {
208 char buf[256];
209 const short l = MIN2<short>(*((short*)pc2), sizeof(buf) - 1);
210 memcpy(buf, (char*)pc2 + sizeof(short), l);
211 buf[l] = '\0';
212
213 p_name[0] = '\0';
214
215 // If it is a C++ name, try and demangle it using the Demangle interface (see demangle.h).
216 char* rest;
217 Name* const name = Demangle(buf, rest);
218 if (name) {
219 const char* const demangled_name = name->Text();
220 if (demangled_name) {
221 strncpy(p_name, demangled_name, namelen-1);
222 p_name[namelen-1] = '\0';
223 }
224 delete name;
225 }
226
227 // Fallback: if demangling did not work, just provide the unmangled name.
228 if (p_name[0] == '\0') {
229 strncpy(p_name, buf, namelen-1);
230 p_name[namelen-1] = '\0';
231 }
232
233 } else {
234 strncpy(p_name, "<nameless function>", namelen-1);
235 p_name[namelen-1] = '\0';
236 }
237 }
238 // Return traceback table, if user wants it.
239 if (p_tb) {
240 (*p_tb) = tb;
241 }
242
243 return 0;
244 }
245
246 // Special implementation of dladdr for Aix based on LoadedLibraries
247 // Note: dladdr returns non-zero for ok, 0 for error!
248 // Note: dladdr is not posix, but a non-standard GNU extension. So this tries to
249 // fulfill the contract of dladdr on Linux (see http://linux.die.net/man/3/dladdr)
250 // Note: addr may be both an AIX function descriptor or a real code pointer
251 // to the entry of a function.
252 extern "C"
253 int dladdr(void* addr, Dl_info* info) {
254
255 if (!addr) {
256 return 0;
257 }
258
259 assert(info, "");
260
261 int rc = 0;
262
263 const char* const ZEROSTRING = "";
264
265 // Always return a string, even if a "" one. Linux dladdr manpage
266 // does not say anything about returning NULL
267 info->dli_fname = ZEROSTRING;
268 info->dli_sname = ZEROSTRING;
269 info->dli_saddr = NULL;
270
271 address p = (address) addr;
272 const LoadedLibraryModule* lib = NULL;
273
274 enum { noclue, code, data } type = noclue;
275
276 trcVerbose("dladdr(%p)...", p);
277
278 // Note: input address may be a function. I accept both a pointer to
279 // the entry of a function and a pointer to the function decriptor.
280 // (see ppc64 ABI)
281 lib = LoadedLibraries::find_for_text_address(p);
282 if (lib) {
283 type = code;
284 }
285
286 if (!lib) {
287 // Not a pointer into any text segment. Is it a function descriptor?
288 const FunctionDescriptor* const pfd = (const FunctionDescriptor*) p;
289 p = pfd->entry();
290 if (p) {
291 lib = LoadedLibraries::find_for_text_address(p);
292 if (lib) {
293 type = code;
294 }
295 }
296 }
297
298 if (!lib) {
299 // Neither direct code pointer nor function descriptor. A data ptr?
300 p = (address)addr;
301 lib = LoadedLibraries::find_for_data_address(p);
302 if (lib) {
303 type = data;
304 }
305 }
306
307 // If we did find the shared library this address belongs to (either
308 // code or data segment) resolve library path and, if possible, the
309 // symbol name.
310 if (lib) {
311 const char* const interned_libpath =
312 dladdr_fixed_strings.intern(lib->get_fullpath());
313 if (interned_libpath) {
314 info->dli_fname = interned_libpath;
315 }
316
317 if (type == code) {
318
319 // For code symbols resolve function name and displacement. Use
320 // displacement to calc start of function.
321 char funcname[256] = "";
322 int displacement = 0;
323
324 if (getFuncName((codeptr_t) p, funcname, sizeof(funcname), &displacement,
325 NULL, NULL, 0) == 0) {
326 if (funcname[0] != '\0') {
327 const char* const interned = dladdr_fixed_strings.intern(funcname);
328 info->dli_sname = interned;
329 trcVerbose("... function name: %s ...", interned);
330 }
331
332 // From the displacement calculate the start of the function.
333 if (displacement != -1) {
334 info->dli_saddr = p - displacement;
335 } else {
336 info->dli_saddr = p;
337 }
338 } else {
339
340 // No traceback table found. Just assume the pointer is it.
341 info->dli_saddr = p;
342
343 }
344
345 } else if (type == data) {
346
347 // For data symbols.
348 info->dli_saddr = p;
349
350 } else {
351 ShouldNotReachHere();
352 }
353
354 rc = 1; // success: return 1 [sic]
355
356 }
357
358 // sanity checks.
359 if (rc) {
360 assert(info->dli_fname, "");
361 assert(info->dli_sname, "");
362 assert(info->dli_saddr, "");
363 }
364
365 return rc; // error: return 0 [sic]
366
367 }