Mercurial > hg > graal-compiler
comparison src/os/bsd/vm/decoder_machO.cpp @ 6258:3b01d0321dfa
7186778: MachO decoder implementation for MacOSX
Summary: Implementation of decoder for Apple's MacOSX. The implementation is based on the patch provided by Kevin Walls.
Reviewed-by: coleenp, kamg, kevinw
author | zgu |
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date | Mon, 30 Jul 2012 10:25:52 -0400 |
parents | d7e3846464d0 |
children | b9a9ed0f8eeb |
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6236:950ed41429e5 | 6258:3b01d0321dfa |
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24 | 24 |
25 #include "precompiled.hpp" | 25 #include "precompiled.hpp" |
26 | 26 |
27 #ifdef __APPLE__ | 27 #ifdef __APPLE__ |
28 #include "decoder_machO.hpp" | 28 #include "decoder_machO.hpp" |
29 | |
30 #include <cxxabi.h> | |
31 #include <mach-o/loader.h> | |
32 #include <mach-o/nlist.h> | |
33 | |
34 | |
35 bool MachODecoder::demangle(const char* symbol, char *buf, int buflen) { | |
36 int status; | |
37 char* result; | |
38 size_t size = (size_t)buflen; | |
39 // Don't pass buf to __cxa_demangle. In case of the 'buf' is too small, | |
40 // __cxa_demangle will call system "realloc" for additional memory, which | |
41 // may use different malloc/realloc mechanism that allocates 'buf'. | |
42 if ((result = abi::__cxa_demangle(symbol, NULL, NULL, &status)) != NULL) { | |
43 jio_snprintf(buf, buflen, "%s", result); | |
44 // call c library's free | |
45 ::free(result); | |
46 return true; | |
47 } | |
48 return false; | |
49 } | |
50 | |
51 bool MachODecoder::decode(address addr, char *buf, | |
52 int buflen, int *offset, const void *mach_base) { | |
53 struct symtab_command * symt = (struct symtab_command *) | |
54 mach_find_command((struct mach_header_64 *)mach_base, LC_SYMTAB); | |
55 if (symt == NULL) { | |
56 DEBUG_ONLY(tty->print_cr("no symtab in mach file at 0x%lx", mach_base)); | |
57 return false; | |
58 } | |
59 uint32_t off = symt->symoff; /* symbol table offset (within this mach file) */ | |
60 uint32_t nsyms = symt->nsyms; /* number of symbol table entries */ | |
61 uint32_t stroff = symt->stroff; /* string table offset */ | |
62 uint32_t strsize = symt->strsize; /* string table size in bytes */ | |
63 | |
64 // iterate through symbol table trying to match our offset | |
65 | |
66 uint32_t addr_relative = (uintptr_t) mach_base - (uintptr_t) addr; // offset we seek in the symtab | |
67 void * symtab_addr = (void*) ((uintptr_t) mach_base + off); | |
68 struct nlist_64 *cur_nlist = (struct nlist_64 *) symtab_addr; | |
69 struct nlist_64 *last_nlist = cur_nlist; // no size stored in an entry, so keep previously seen nlist | |
70 | |
71 int32_t found_strx = 0; | |
72 int32_t found_symval = 0; | |
73 | |
74 for (uint32_t i=0; i < nsyms; i++) { | |
75 uint32_t this_value = cur_nlist->n_value; | |
76 | |
77 if (addr_relative == this_value) { | |
78 found_strx = cur_nlist->n_un.n_strx; | |
79 found_symval = this_value; | |
80 break; | |
81 } else if (addr_relative > this_value) { | |
82 // gone past it, use previously seen nlist: | |
83 found_strx = last_nlist->n_un.n_strx; | |
84 found_symval = last_nlist->n_value; | |
85 break; | |
86 } | |
87 last_nlist = cur_nlist; | |
88 cur_nlist = cur_nlist + sizeof(struct nlist_64); | |
89 } | |
90 if (found_strx == 0) { | |
91 return false; | |
92 } | |
93 // write the offset: | |
94 *offset = addr_relative - found_symval; | |
95 | |
96 // lookup found_strx in the string table | |
97 char * symname = mach_find_in_stringtable((char*) ((uintptr_t)mach_base + stroff), strsize, found_strx); | |
98 if (symname) { | |
99 strncpy(buf, symname, buflen); | |
100 return true; | |
101 } | |
102 DEBUG_ONLY(tty->print_cr("no string or null string found.")); | |
103 return false; | |
104 } | |
105 | |
106 void* MachODecoder::mach_find_command(struct mach_header_64 * mach_base, uint32_t command_wanted) { | |
107 // possibly verify it is a mach_header, use magic number. | |
108 // commands begin immediately after the header. | |
109 struct load_command *pos = (struct load_command *) mach_base + sizeof(struct mach_header_64); | |
110 for (uint32_t i = 0; i < mach_base->ncmds; i++) { | |
111 struct load_command *this_cmd = (struct load_command *) pos; | |
112 if (this_cmd->cmd == command_wanted) { | |
113 return pos; | |
114 } | |
115 int cmdsize = this_cmd->cmdsize; | |
116 pos += cmdsize; | |
117 } | |
118 return NULL; | |
119 } | |
120 | |
121 char* MachODecoder::mach_find_in_stringtable(char *strtab, uint32_t tablesize, int strx_wanted) { | |
122 | |
123 if (strx_wanted == 0) { | |
124 return NULL; | |
125 } | |
126 char *strtab_end = strtab + tablesize; | |
127 | |
128 // find the first string, skip over the space char | |
129 // (or the four zero bytes we see e.g. in libclient) | |
130 if (*strtab == ' ') { | |
131 strtab++; | |
132 if (*strtab != 0) { | |
133 DEBUG_ONLY(tty->print_cr("string table has leading space but no following zero.")); | |
134 return NULL; | |
135 } | |
136 strtab++; | |
137 } else { | |
138 if ((uint32_t) *strtab != 0) { | |
139 DEBUG_ONLY(tty->print_cr("string table without leading space or leading int of zero.")); | |
140 return NULL; | |
141 } | |
142 strtab+=4; | |
143 } | |
144 // read the real strings starting at index 1 | |
145 int cur_strx = 1; | |
146 while (strtab < strtab_end) { | |
147 if (cur_strx == strx_wanted) { | |
148 return strtab; | |
149 } | |
150 // find start of next string | |
151 while (*strtab != 0) { | |
152 strtab++; | |
153 } | |
154 strtab++; // skip the terminating zero | |
155 cur_strx++; | |
156 } | |
157 DEBUG_ONLY(tty->print_cr("string number %d not found.", strx_wanted)); | |
158 return NULL; | |
159 } | |
160 | |
161 | |
29 #endif | 162 #endif |
30 | 163 |
31 | 164 |