1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/os/aix/vm/porting_aix.cpp Fri Sep 06 20:16:09 2013 +0200
1.3 @@ -0,0 +1,367 @@
1.4 +/*
1.5 + * Copyright 2012, 2013 SAP AG. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "asm/assembler.hpp"
1.29 +#include "loadlib_aix.hpp"
1.30 +#include "porting_aix.hpp"
1.31 +#include "utilities/debug.hpp"
1.32 +
1.33 +#include <demangle.h>
1.34 +#include <sys/debug.h>
1.35 +
1.36 +//////////////////////////////////
1.37 +// Provide implementation for dladdr based on LoadedLibraries pool and
1.38 +// traceback table scan (see getFuncName).
1.39 +
1.40 +// Search traceback table in stack,
1.41 +// return procedure name from trace back table.
1.42 +#define MAX_FUNC_SEARCH_LEN 0x10000
1.43 +// Any PC below this value is considered toast.
1.44 +#define MINIMUM_VALUE_FOR_PC ((unsigned int*)0x1024)
1.45 +
1.46 +#define PTRDIFF_BYTES(p1,p2) (((ptrdiff_t)p1) - ((ptrdiff_t)p2))
1.47 +
1.48 +// Align a pointer without having to cast.
1.49 +inline char* align_ptr_up(char* ptr, intptr_t alignment) {
1.50 + return (char*) align_size_up((intptr_t)ptr, alignment);
1.51 +}
1.52 +
1.53 +// Trace if verbose to tty.
1.54 +// I use these now instead of the Xtrace system because the latter is
1.55 +// not available at init time, hence worthless. Until we fix this, all
1.56 +// tracing here is done with -XX:+Verbose.
1.57 +#define trcVerbose(fmt, ...) { \
1.58 + if (Verbose) { \
1.59 + fprintf(stderr, fmt, ##__VA_ARGS__); \
1.60 + fputc('\n', stderr); fflush(stderr); \
1.61 + } \
1.62 +}
1.63 +#define ERRBYE(s) { trcVerbose(s); return -1; }
1.64 +
1.65 +// Unfortunately, the interface of dladdr makes the implementator
1.66 +// responsible for maintaining memory for function name/library
1.67 +// name. I guess this is because most OS's keep those values as part
1.68 +// of the mapped executable image ready to use. On AIX, this doesn't
1.69 +// work, so I have to keep the returned strings. For now, I do this in
1.70 +// a primitive string map. Should this turn out to be a performance
1.71 +// problem, a better hashmap has to be used.
1.72 +class fixed_strings {
1.73 + struct node {
1.74 + char* v;
1.75 + node* next;
1.76 + };
1.77 +
1.78 + node* first;
1.79 +
1.80 + public:
1.81 +
1.82 + fixed_strings() : first(0) {}
1.83 + ~fixed_strings() {
1.84 + node* n = first;
1.85 + while (n) {
1.86 + node* p = n;
1.87 + n = n->next;
1.88 + free(p->v);
1.89 + delete p;
1.90 + }
1.91 + }
1.92 +
1.93 + char* intern(const char* s) {
1.94 + for (node* n = first; n; n = n->next) {
1.95 + if (strcmp(n->v, s) == 0) {
1.96 + return n->v;
1.97 + }
1.98 + }
1.99 + node* p = new node;
1.100 + p->v = strdup(s);
1.101 + p->next = first;
1.102 + first = p;
1.103 + return p->v;
1.104 + }
1.105 +};
1.106 +
1.107 +static fixed_strings dladdr_fixed_strings;
1.108 +
1.109 +// Given a code pointer, returns the function name and the displacement.
1.110 +// Function looks for the traceback table at the end of the function.
1.111 +extern "C" int getFuncName(
1.112 + codeptr_t pc, // [in] program counter
1.113 + char* p_name, size_t namelen, // [out] optional: function name ("" if not available)
1.114 + int* p_displacement, // [out] optional: displacement (-1 if not available)
1.115 + const struct tbtable** p_tb, // [out] optional: ptr to traceback table to get further
1.116 + // information (NULL if not available)
1.117 + char* p_errmsg, size_t errmsglen // [out] optional: user provided buffer for error messages
1.118 + ) {
1.119 + struct tbtable* tb = 0;
1.120 + unsigned int searchcount = 0;
1.121 +
1.122 + // initialize output parameters
1.123 + if (p_name && namelen > 0) {
1.124 + *p_name = '\0';
1.125 + }
1.126 + if (p_errmsg && errmsglen > 0) {
1.127 + *p_errmsg = '\0';
1.128 + }
1.129 + if (p_displacement) {
1.130 + *p_displacement = -1;
1.131 + }
1.132 + if (p_tb) {
1.133 + *p_tb = NULL;
1.134 + }
1.135 +
1.136 + // weed out obvious bogus states
1.137 + if (pc < MINIMUM_VALUE_FOR_PC) {
1.138 + ERRBYE("invalid program counter");
1.139 + }
1.140 +
1.141 + codeptr_t pc2 = pc;
1.142 +
1.143 + // make sure the pointer is word aligned.
1.144 + pc2 = (codeptr_t) align_ptr_up((char*)pc2, 4);
1.145 +
1.146 + // Find start of traceback table.
1.147 + // (starts after code, is marked by word-aligned (32bit) zeros)
1.148 + while ((*pc2 != NULL) && (searchcount++ < MAX_FUNC_SEARCH_LEN)) {
1.149 + pc2++;
1.150 + }
1.151 + if (*pc2 != 0) {
1.152 + ERRBYE("could not find traceback table within 5000 bytes of program counter");
1.153 + }
1.154 + //
1.155 + // Set up addressability to the traceback table
1.156 + //
1.157 + tb = (struct tbtable*) (pc2 + 1);
1.158 +
1.159 + // Is this really a traceback table? No way to be sure but
1.160 + // some indicators we can check.
1.161 + if (tb->tb.lang >= 0xf && tb->tb.lang <= 0xfb) {
1.162 + // Language specifiers, go from 0 (C) to 14 (Objective C).
1.163 + // According to spec, 0xf-0xfa reserved, 0xfb-0xff reserved for ibm.
1.164 + ERRBYE("not a traceback table");
1.165 + }
1.166 +
1.167 + // Existence of fields in the tbtable extension are contingent upon
1.168 + // specific fields in the base table. Check for their existence so
1.169 + // that we can address the function name if it exists.
1.170 + pc2 = (codeptr_t) tb +
1.171 + sizeof(struct tbtable_short)/sizeof(int);
1.172 + if (tb->tb.fixedparms != 0 || tb->tb.floatparms != 0)
1.173 + pc2++;
1.174 +
1.175 + if (tb->tb.has_tboff == TRUE) {
1.176 +
1.177 + // I want to know the displacement
1.178 + const unsigned int tb_offset = *pc2;
1.179 + codeptr_t start_of_procedure =
1.180 + (codeptr_t)(((char*)tb) - 4 - tb_offset); // (-4 to omit leading 0000)
1.181 +
1.182 + // Weed out the cases where we did find the wrong traceback table.
1.183 + if (pc < start_of_procedure) {
1.184 + ERRBYE("could not find (the real) traceback table within 5000 bytes of program counter");
1.185 + }
1.186 +
1.187 + // return the displacement
1.188 + if (p_displacement) {
1.189 + (*p_displacement) = (int) PTRDIFF_BYTES(pc, start_of_procedure);
1.190 + }
1.191 +
1.192 + pc2++;
1.193 + } else {
1.194 + // return -1 for displacement
1.195 + if (p_displacement) {
1.196 + (*p_displacement) = -1;
1.197 + }
1.198 + }
1.199 +
1.200 + if (tb->tb.int_hndl == TRUE)
1.201 + pc2++;
1.202 +
1.203 + if (tb->tb.has_ctl == TRUE)
1.204 + pc2 += (*pc2) + 1; // don't care
1.205 +
1.206 + //
1.207 + // return function name if it exists.
1.208 + //
1.209 + if (p_name && namelen > 0) {
1.210 + if (tb->tb.name_present) {
1.211 + char buf[256];
1.212 + const short l = MIN2<short>(*((short*)pc2), sizeof(buf) - 1);
1.213 + memcpy(buf, (char*)pc2 + sizeof(short), l);
1.214 + buf[l] = '\0';
1.215 +
1.216 + p_name[0] = '\0';
1.217 +
1.218 + // If it is a C++ name, try and demangle it using the Demangle interface (see demangle.h).
1.219 + char* rest;
1.220 + Name* const name = Demangle(buf, rest);
1.221 + if (name) {
1.222 + const char* const demangled_name = name->Text();
1.223 + if (demangled_name) {
1.224 + strncpy(p_name, demangled_name, namelen-1);
1.225 + p_name[namelen-1] = '\0';
1.226 + }
1.227 + delete name;
1.228 + }
1.229 +
1.230 + // Fallback: if demangling did not work, just provide the unmangled name.
1.231 + if (p_name[0] == '\0') {
1.232 + strncpy(p_name, buf, namelen-1);
1.233 + p_name[namelen-1] = '\0';
1.234 + }
1.235 +
1.236 + } else {
1.237 + strncpy(p_name, "<nameless function>", namelen-1);
1.238 + p_name[namelen-1] = '\0';
1.239 + }
1.240 + }
1.241 + // Return traceback table, if user wants it.
1.242 + if (p_tb) {
1.243 + (*p_tb) = tb;
1.244 + }
1.245 +
1.246 + return 0;
1.247 +}
1.248 +
1.249 +// Special implementation of dladdr for Aix based on LoadedLibraries
1.250 +// Note: dladdr returns non-zero for ok, 0 for error!
1.251 +// Note: dladdr is not posix, but a non-standard GNU extension. So this tries to
1.252 +// fulfill the contract of dladdr on Linux (see http://linux.die.net/man/3/dladdr)
1.253 +// Note: addr may be both an AIX function descriptor or a real code pointer
1.254 +// to the entry of a function.
1.255 +extern "C"
1.256 +int dladdr(void* addr, Dl_info* info) {
1.257 +
1.258 + if (!addr) {
1.259 + return 0;
1.260 + }
1.261 +
1.262 + assert(info, "");
1.263 +
1.264 + int rc = 0;
1.265 +
1.266 + const char* const ZEROSTRING = "";
1.267 +
1.268 + // Always return a string, even if a "" one. Linux dladdr manpage
1.269 + // does not say anything about returning NULL
1.270 + info->dli_fname = ZEROSTRING;
1.271 + info->dli_sname = ZEROSTRING;
1.272 + info->dli_saddr = NULL;
1.273 +
1.274 + address p = (address) addr;
1.275 + const LoadedLibraryModule* lib = NULL;
1.276 +
1.277 + enum { noclue, code, data } type = noclue;
1.278 +
1.279 + trcVerbose("dladdr(%p)...", p);
1.280 +
1.281 + // Note: input address may be a function. I accept both a pointer to
1.282 + // the entry of a function and a pointer to the function decriptor.
1.283 + // (see ppc64 ABI)
1.284 + lib = LoadedLibraries::find_for_text_address(p);
1.285 + if (lib) {
1.286 + type = code;
1.287 + }
1.288 +
1.289 + if (!lib) {
1.290 + // Not a pointer into any text segment. Is it a function descriptor?
1.291 + const FunctionDescriptor* const pfd = (const FunctionDescriptor*) p;
1.292 + p = pfd->entry();
1.293 + if (p) {
1.294 + lib = LoadedLibraries::find_for_text_address(p);
1.295 + if (lib) {
1.296 + type = code;
1.297 + }
1.298 + }
1.299 + }
1.300 +
1.301 + if (!lib) {
1.302 + // Neither direct code pointer nor function descriptor. A data ptr?
1.303 + p = (address)addr;
1.304 + lib = LoadedLibraries::find_for_data_address(p);
1.305 + if (lib) {
1.306 + type = data;
1.307 + }
1.308 + }
1.309 +
1.310 + // If we did find the shared library this address belongs to (either
1.311 + // code or data segment) resolve library path and, if possible, the
1.312 + // symbol name.
1.313 + if (lib) {
1.314 + const char* const interned_libpath =
1.315 + dladdr_fixed_strings.intern(lib->get_fullpath());
1.316 + if (interned_libpath) {
1.317 + info->dli_fname = interned_libpath;
1.318 + }
1.319 +
1.320 + if (type == code) {
1.321 +
1.322 + // For code symbols resolve function name and displacement. Use
1.323 + // displacement to calc start of function.
1.324 + char funcname[256] = "";
1.325 + int displacement = 0;
1.326 +
1.327 + if (getFuncName((codeptr_t) p, funcname, sizeof(funcname), &displacement,
1.328 + NULL, NULL, 0) == 0) {
1.329 + if (funcname[0] != '\0') {
1.330 + const char* const interned = dladdr_fixed_strings.intern(funcname);
1.331 + info->dli_sname = interned;
1.332 + trcVerbose("... function name: %s ...", interned);
1.333 + }
1.334 +
1.335 + // From the displacement calculate the start of the function.
1.336 + if (displacement != -1) {
1.337 + info->dli_saddr = p - displacement;
1.338 + } else {
1.339 + info->dli_saddr = p;
1.340 + }
1.341 + } else {
1.342 +
1.343 + // No traceback table found. Just assume the pointer is it.
1.344 + info->dli_saddr = p;
1.345 +
1.346 + }
1.347 +
1.348 + } else if (type == data) {
1.349 +
1.350 + // For data symbols.
1.351 + info->dli_saddr = p;
1.352 +
1.353 + } else {
1.354 + ShouldNotReachHere();
1.355 + }
1.356 +
1.357 + rc = 1; // success: return 1 [sic]
1.358 +
1.359 + }
1.360 +
1.361 + // sanity checks.
1.362 + if (rc) {
1.363 + assert(info->dli_fname, "");
1.364 + assert(info->dli_sname, "");
1.365 + assert(info->dli_saddr, "");
1.366 + }
1.367 +
1.368 + return rc; // error: return 0 [sic]
1.369 +
1.370 +}
