From dff1629750aa81c871e137a1bef34ecb3aed32c9 Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Thu, 4 Jun 2009 00:43:11 +0000 Subject: [PATCH] * layout.cc (Layout::section_name_mapping): New array, replacing Layout::linkonce_mapping. (Layout::section_name_mapping_count): New variable, replacing Layout::linkonce_mapping_count. (Layout::linkonce_output_name): Remove. (Layout::output_section_name): Rewrite. * layout.h (class Layout): Rename Linkonce_mapping to Section_name_mapping, linkonce_mapping to section_name_mapping, linkonce_mapping_count to section_name_mapping_count. Don't declare linkonce_output_name. --- gold/ChangeLog | 13 ++++ gold/layout.cc | 161 +++++++++++++++++++------------------------------ gold/layout.h | 13 ++-- 3 files changed, 78 insertions(+), 109 deletions(-) diff --git a/gold/ChangeLog b/gold/ChangeLog index d08d57dd6bb..7408ac61a62 100644 --- a/gold/ChangeLog +++ b/gold/ChangeLog @@ -1,3 +1,16 @@ +2009-06-03 Ian Lance Taylor + + * layout.cc (Layout::section_name_mapping): New array, replacing + Layout::linkonce_mapping. + (Layout::section_name_mapping_count): New variable, replacing + Layout::linkonce_mapping_count. + (Layout::linkonce_output_name): Remove. + (Layout::output_section_name): Rewrite. + * layout.h (class Layout): Rename Linkonce_mapping to + Section_name_mapping, linkonce_mapping to section_name_mapping, + linkonce_mapping_count to section_name_mapping_count. Don't + declare linkonce_output_name. + 2009-06-03 Doug Kwan * gold/arm.cc (namespace utils): New. diff --git a/gold/layout.cc b/gold/layout.cc index a651d0650d9..7db10c7685c 100644 --- a/gold/layout.cc +++ b/gold/layout.cc @@ -2841,57 +2841,58 @@ Layout::finish_dynamic_section(const Input_objects* input_objects, odyn->add_constant(elfcpp::DT_FLAGS_1, flags); } -// The mapping of .gnu.linkonce section names to real section names. +// The mapping of input section name prefixes to output section names. +// In some cases one prefix is itself a prefix of another prefix; in +// such a case the longer prefix must come first. These prefixes are +// based on the GNU linker default ELF linker script. #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 } -const Layout::Linkonce_mapping Layout::linkonce_mapping[] = -{ - MAPPING_INIT("d.rel.ro.local", ".data.rel.ro.local"), // Before "d.rel.ro". - MAPPING_INIT("d.rel.ro", ".data.rel.ro"), // Before "d". - MAPPING_INIT("t", ".text"), - MAPPING_INIT("r", ".rodata"), - MAPPING_INIT("d", ".data"), - MAPPING_INIT("b", ".bss"), - MAPPING_INIT("s", ".sdata"), - MAPPING_INIT("sb", ".sbss"), - MAPPING_INIT("s2", ".sdata2"), - MAPPING_INIT("sb2", ".sbss2"), - MAPPING_INIT("wi", ".debug_info"), - MAPPING_INIT("td", ".tdata"), - MAPPING_INIT("tb", ".tbss"), - MAPPING_INIT("lr", ".lrodata"), - MAPPING_INIT("l", ".ldata"), - MAPPING_INIT("lb", ".lbss"), +const Layout::Section_name_mapping Layout::section_name_mapping[] = +{ + MAPPING_INIT(".text.", ".text"), + MAPPING_INIT(".ctors.", ".ctors"), + MAPPING_INIT(".dtors.", ".dtors"), + MAPPING_INIT(".rodata.", ".rodata"), + MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"), + MAPPING_INIT(".data.rel.ro", ".data.rel.ro"), + MAPPING_INIT(".data.", ".data"), + MAPPING_INIT(".bss.", ".bss"), + MAPPING_INIT(".tdata.", ".tdata"), + MAPPING_INIT(".tbss.", ".tbss"), + MAPPING_INIT(".init_array.", ".init_array"), + MAPPING_INIT(".fini_array.", ".fini_array"), + MAPPING_INIT(".sdata.", ".sdata"), + MAPPING_INIT(".sbss.", ".sbss"), + // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled + // differently depending on whether it is creating a shared library. + MAPPING_INIT(".sdata2.", ".sdata"), + MAPPING_INIT(".sbss2.", ".sbss"), + MAPPING_INIT(".lrodata.", ".lrodata"), + MAPPING_INIT(".ldata.", ".ldata"), + MAPPING_INIT(".lbss.", ".lbss"), + MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"), + MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"), + MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"), + MAPPING_INIT(".gnu.linkonce.t.", ".text"), + MAPPING_INIT(".gnu.linkonce.r.", ".rodata"), + MAPPING_INIT(".gnu.linkonce.d.", ".data"), + MAPPING_INIT(".gnu.linkonce.b.", ".bss"), + MAPPING_INIT(".gnu.linkonce.s.", ".sdata"), + MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"), + MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"), + MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"), + MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"), + MAPPING_INIT(".gnu.linkonce.td.", ".tdata"), + MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"), + MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"), + MAPPING_INIT(".gnu.linkonce.l.", ".ldata"), + MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"), }; #undef MAPPING_INIT -const int Layout::linkonce_mapping_count = - sizeof(Layout::linkonce_mapping) / sizeof(Layout::linkonce_mapping[0]); - -// Return the name of the output section to use for a .gnu.linkonce -// section. This is based on the default ELF linker script of the old -// GNU linker. For example, we map a name like ".gnu.linkonce.t.foo" -// to ".text". Set *PLEN to the length of the name. *PLEN is -// initialized to the length of NAME. - -const char* -Layout::linkonce_output_name(const char* name, size_t *plen) -{ - const char* s = name + sizeof(".gnu.linkonce") - 1; - if (*s != '.') - return name; - ++s; - const Linkonce_mapping* plm = linkonce_mapping; - for (int i = 0; i < linkonce_mapping_count; ++i, ++plm) - { - if (strncmp(s, plm->from, plm->fromlen) == 0 && s[plm->fromlen] == '.') - { - *plen = plm->tolen; - return plm->to; - } - } - return name; -} +const int Layout::section_name_mapping_count = + (sizeof(Layout::section_name_mapping) + / sizeof(Layout::section_name_mapping[0])); // Choose the output section name to use given an input section name. // Set *PLEN to the length of the name. *PLEN is initialized to the @@ -2900,13 +2901,6 @@ Layout::linkonce_output_name(const char* name, size_t *plen) const char* Layout::output_section_name(const char* name, size_t* plen) { - if (Layout::is_linkonce(name)) - { - // .gnu.linkonce sections are laid out as though they were named - // for the sections are placed into. - return Layout::linkonce_output_name(name, plen); - } - // gcc 4.3 generates the following sorts of section names when it // needs a section name specific to a function: // .text.FN @@ -2933,58 +2927,25 @@ Layout::output_section_name(const char* name, size_t* plen) // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the // GNU linker maps to .rodata. - // The .data.rel.ro sections enable a security feature triggered by - // the -z relro option. Section which need to be relocated at - // program startup time but which may be readonly after startup are - // grouped into .data.rel.ro. They are then put into a PT_GNU_RELRO - // segment. The dynamic linker will make that segment writable, - // perform relocations, and then make it read-only. FIXME: We do - // not yet implement this optimization. + // The .data.rel.ro sections are used with -z relro. The sections + // are recognized by name. We use the same names that the GNU + // linker does for these sections. - // It is hard to handle this in a principled way. + // It is hard to handle this in a principled way, so we don't even + // try. We use a table of mappings. If the input section name is + // not found in the table, we simply use it as the output section + // name. - // These are the rules we follow: - - // If the section name has no initial '.', or no dot other than an - // initial '.', we use the name unchanged (i.e., "mysection" and - // ".text" are unchanged). - - // If the name starts with '.note', we keep it unchanged (e.g. to - // avoid truncating '.note.ABI-tag' to '.note'). - - // If the name starts with ".data.rel.ro.local" we use - // ".data.rel.ro.local". - - // If the name starts with ".data.rel.ro" we use ".data.rel.ro". - - // Otherwise, we drop the second '.' and everything that comes after - // it (i.e., ".text.XXX" becomes ".text"). - - const char* s = name; - if (*s != '.') - return name; - ++s; - const char* sdot = strchr(s, '.'); - if (sdot == NULL) - return name; - if (strncmp(name, ".note.", 6) == 0) - return name; - - const char* const data_rel_ro_local = ".data.rel.ro.local"; - if (strncmp(name, data_rel_ro_local, strlen(data_rel_ro_local)) == 0) - { - *plen = strlen(data_rel_ro_local); - return data_rel_ro_local; - } - - const char* const data_rel_ro = ".data.rel.ro"; - if (strncmp(name, data_rel_ro, strlen(data_rel_ro)) == 0) + const Section_name_mapping* psnm = section_name_mapping; + for (int i = 0; i < section_name_mapping_count; ++i, ++psnm) { - *plen = strlen(data_rel_ro); - return data_rel_ro; + if (strncmp(name, psnm->from, psnm->fromlen) == 0) + { + *plen = psnm->tolen; + return psnm->to; + } } - *plen = sdot - name; return name; } diff --git a/gold/layout.h b/gold/layout.h index 0a9146bdf4f..93ecd8544de 100644 --- a/gold/layout.h +++ b/gold/layout.h @@ -433,16 +433,16 @@ class Layout Layout(const Layout&); Layout& operator=(const Layout&); - // Mapping from .gnu.linkonce section names to output section names. - struct Linkonce_mapping + // Mapping from input section names to output section names. + struct Section_name_mapping { const char* from; int fromlen; const char* to; int tolen; }; - static const Linkonce_mapping linkonce_mapping[]; - static const int linkonce_mapping_count; + static const Section_name_mapping section_name_mapping[]; + static const int section_name_mapping_count; // During a relocatable link, a list of group sections and // signatures. @@ -556,11 +556,6 @@ class Layout static const char* output_section_name(const char* name, size_t* plen); - // Return the output section name to use for a linkonce section - // name. PLEN is as for output_section_name. - static const char* - linkonce_output_name(const char* name, size_t* plen); - // Return the number of allocated output sections. size_t allocated_output_section_count() const; -- 2.30.2