1 //===- ELFEmulation.cpp ---------------------------------------------------===//
2 //
3 //                     The MCLinker Project
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 #include "mcld/Target/ELFEmulation.h"
10 #include "mcld/LinkerScript.h"
11 #include "mcld/LinkerConfig.h"
12 #include "mcld/Script/InputSectDesc.h"
13 
14 #include <llvm/Support/Host.h>
15 
16 namespace mcld {
17 
18 struct NameMap {
19   const char* from;  ///< the prefix of the input string. (match FROM*)
20   const char* to;    ///< the output string.
21   InputSectDesc::KeepPolicy policy;  /// mark whether the input is kept in GC
22 };
23 
24 static const NameMap map[] = {
25     {".text*", ".text", InputSectDesc::NoKeep},
26     {".rodata*", ".rodata", InputSectDesc::NoKeep},
27     {".data.rel.ro.local*", ".data.rel.ro.local", InputSectDesc::NoKeep},
28     {".data.rel.ro*", ".data.rel.ro", InputSectDesc::NoKeep},
29     {".data*", ".data", InputSectDesc::NoKeep},
30     {".bss*", ".bss", InputSectDesc::NoKeep},
31     {".tdata*", ".tdata", InputSectDesc::NoKeep},
32     {".tbss*", ".tbss", InputSectDesc::NoKeep},
33     {".init", ".init", InputSectDesc::Keep},
34     {".fini", ".fini", InputSectDesc::Keep},
35     {".preinit_array*", ".preinit_array", InputSectDesc::Keep},
36     {".init_array*", ".init_array", InputSectDesc::Keep},
37     {".fini_array*", ".fini_array", InputSectDesc::Keep},
38     // TODO: Support DT_INIT_ARRAY for all constructors?
39     {".ctors*", ".ctors", InputSectDesc::Keep},
40     {".dtors*", ".dtors", InputSectDesc::Keep},
41     {".jcr", ".jcr", InputSectDesc::Keep},
42     // FIXME: in GNU ld, if we are creating a shared object .sdata2 and .sbss2
43     // sections would be handled differently.
44     {".sdata2*", ".sdata", InputSectDesc::NoKeep},
45     {".sbss2*", ".sbss", InputSectDesc::NoKeep},
46     {".sdata*", ".sdata", InputSectDesc::NoKeep},
47     {".sbss*", ".sbss", InputSectDesc::NoKeep},
48     {".lrodata*", ".lrodata", InputSectDesc::NoKeep},
49     {".ldata*", ".ldata", InputSectDesc::NoKeep},
50     {".lbss*", ".lbss", InputSectDesc::NoKeep},
51     {".gcc_except_table*", ".gcc_except_table", InputSectDesc::Keep},
52     {".gnu.linkonce.d.rel.ro.local*", ".data.rel.ro.local", InputSectDesc::NoKeep},  // NOLINT
53     {".gnu.linkonce.d.rel.ro*", ".data.rel.ro", InputSectDesc::NoKeep},
54     {".gnu.linkonce.r*", ".rodata", InputSectDesc::NoKeep},
55     {".gnu.linkonce.d*", ".data", InputSectDesc::NoKeep},
56     {".gnu.linkonce.b*", ".bss", InputSectDesc::NoKeep},
57     {".gnu.linkonce.sb2*", ".sbss", InputSectDesc::NoKeep},
58     {".gnu.linkonce.sb*", ".sbss", InputSectDesc::NoKeep},
59     {".gnu.linkonce.s2*", ".sdata", InputSectDesc::NoKeep},
60     {".gnu.linkonce.s*", ".sdata", InputSectDesc::NoKeep},
61     {".gnu.linkonce.wi*", ".debug_info", InputSectDesc::NoKeep},
62     {".gnu.linkonce.td*", ".tdata", InputSectDesc::NoKeep},
63     {".gnu.linkonce.tb*", ".tbss", InputSectDesc::NoKeep},
64     {".gnu.linkonce.t*", ".text", InputSectDesc::NoKeep},
65     {".gnu.linkonce.lr*", ".lrodata", InputSectDesc::NoKeep},
66     {".gnu.linkonce.lb*", ".lbss", InputSectDesc::NoKeep},
67     {".gnu.linkonce.l*", ".ldata", InputSectDesc::NoKeep},
68 };
69 
70 // FIXME: LinkerConfig& pConfig should be constant
MCLDEmulateELF(LinkerScript & pScript,LinkerConfig & pConfig)71 bool MCLDEmulateELF(LinkerScript& pScript, LinkerConfig& pConfig) {
72   // set up section map
73   if (pConfig.options().getScriptList().empty() &&
74       pConfig.codeGenType() != LinkerConfig::Object) {
75     const unsigned int map_size = (sizeof(map) / sizeof(map[0]));
76     for (unsigned int i = 0; i < map_size; ++i) {
77       std::pair<SectionMap::mapping, bool> res =
78           pScript.sectionMap().insert(map[i].from, map[i].to, map[i].policy);
79       if (!res.second)
80         return false;
81     }
82   } else {
83     // FIXME: this is the hack to help assignment processing in current
84     // implementation.
85     pScript.sectionMap().insert("", "");
86   }
87 
88   if (!pConfig.options().nostdlib()) {
89     // TODO: check if user sets the default search path instead via -Y option
90     // set up default search path
91     switch (pConfig.targets().triple().getOS()) {
92       case llvm::Triple::NetBSD:
93         pScript.directories().insert("=/usr/lib");
94         break;
95       case llvm::Triple::Win32:
96         pScript.directories().insert("=/mingw/lib");
97         break;
98       default:
99         pScript.directories().insert("=/lib");
100         pScript.directories().insert("=/usr/lib");
101         break;
102     }
103   }
104   return true;
105 }
106 
107 }  // namespace mcld
108