* 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.
This commit is contained in:
Ian Lance Taylor 2009-06-04 00:43:11 +00:00
parent db468abb98
commit dff1629750
3 changed files with 77 additions and 108 deletions

View File

@ -1,3 +1,16 @@
2009-06-03 Ian Lance Taylor <iant@google.com>
* 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 <dougkwan@google.com>
* gold/arm.cc (namespace utils): New.

View File

@ -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[] =
const Layout::Section_name_mapping Layout::section_name_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"),
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)
const Section_name_mapping* psnm = section_name_mapping;
for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
{
*plen = strlen(data_rel_ro_local);
return data_rel_ro_local;
if (strncmp(name, psnm->from, psnm->fromlen) == 0)
{
*plen = psnm->tolen;
return psnm->to;
}
}
const char* const data_rel_ro = ".data.rel.ro";
if (strncmp(name, data_rel_ro, strlen(data_rel_ro)) == 0)
{
*plen = strlen(data_rel_ro);
return data_rel_ro;
}
*plen = sdot - name;
return name;
}

View File

@ -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;