diff options
Diffstat (limited to 'gcc/varasm.c')
| -rw-r--r-- | gcc/varasm.c | 261 |
1 files changed, 191 insertions, 70 deletions
diff --git a/gcc/varasm.c b/gcc/varasm.c index ea0b59c..ce5d449 100644 --- a/gcc/varasm.c +++ b/gcc/varasm.c @@ -43,6 +43,7 @@ along with GCC; see the file COPYING3. If not see #include "fold-const.h" #include "stor-layout.h" #include "varasm.h" +#include "version.h" #include "flags.h" #include "stmt.h" #include "expr.h" @@ -58,6 +59,8 @@ along with GCC; see the file COPYING3. If not see #include "rtl-iter.h" #include "file-prefix-map.h" /* remap_debug_filename() */ #include "alloc-pool.h" +#include "toplev.h" +#include "opts.h" #ifdef XCOFF_DEBUGGING_INFO #include "xcoffout.h" /* Needed for external data declarations. */ @@ -277,16 +280,28 @@ get_noswitch_section (unsigned int flags, noswitch_section_callback callback) } /* Return the named section structure associated with NAME. Create - a new section with the given fields if no such structure exists. */ + a new section with the given fields if no such structure exists. + When NOT_EXISTING, then fail if the section already exists. Return + the existing section if the SECTION_RETAIN bit doesn't match. Set + the SECTION_WRITE | SECTION_RELRO bits on the the existing section + if one of the section flags is SECTION_WRITE | SECTION_RELRO and the + other has none of these flags in named sections and either the section + hasn't been declared yet or has been declared as writable. */ section * -get_section (const char *name, unsigned int flags, tree decl) +get_section (const char *name, unsigned int flags, tree decl, + bool not_existing) { section *sect, **slot; slot = section_htab->find_slot_with_hash (name, htab_hash_string (name), INSERT); flags |= SECTION_NAMED; + if (SUPPORTS_SHF_GNU_RETAIN + && decl != nullptr + && DECL_P (decl) + && DECL_PRESERVE_P (decl)) + flags |= SECTION_RETAIN; if (*slot == NULL) { sect = ggc_alloc<section> (); @@ -297,6 +312,9 @@ get_section (const char *name, unsigned int flags, tree decl) } else { + if (not_existing) + internal_error ("Section already exists: %qs", name); + sect = *slot; /* It is fine if one of the sections has SECTION_NOTYPE as long as the other has none of the contrary flags (see the logic at the end @@ -330,6 +348,11 @@ get_section (const char *name, unsigned int flags, tree decl) sect->common.flags |= (SECTION_WRITE | SECTION_RELRO); return sect; } + /* If the SECTION_RETAIN bit doesn't match, return and switch + to a new section later. */ + if ((sect->common.flags & SECTION_RETAIN) + != (flags & SECTION_RETAIN)) + return sect; /* Sanity check user variables for flag changes. */ if (sect->named.decl != NULL && DECL_P (sect->named.decl) @@ -464,6 +487,7 @@ resolve_unique_section (tree decl, int reloc ATTRIBUTE_UNUSED, if (DECL_SECTION_NAME (decl) == NULL && targetm_common.have_named_sections && (flag_function_or_data_sections + || (SUPPORTS_SHF_GNU_RETAIN && DECL_PRESERVE_P (decl)) || DECL_COMDAT_GROUP (decl))) { targetm.asm_out.unique_section (decl, reloc); @@ -727,12 +751,26 @@ switch_to_other_text_partition (void) switch_to_section (current_function_section ()); } -/* Return the read-only data section associated with function DECL. */ +/* Return the read-only or relocated read-only data section + associated with function DECL. */ section * -default_function_rodata_section (tree decl) +default_function_rodata_section (tree decl, bool relocatable) { - if (decl != NULL_TREE && DECL_SECTION_NAME (decl)) + const char* sname; + unsigned int flags; + + flags = 0; + + if (relocatable) + { + sname = ".data.rel.ro.local"; + flags = (SECTION_WRITE | SECTION_RELRO); + } + else + sname = ".rodata"; + + if (decl && DECL_SECTION_NAME (decl)) { const char *name = DECL_SECTION_NAME (decl); @@ -745,38 +783,56 @@ default_function_rodata_section (tree decl) dot = strchr (name + 1, '.'); if (!dot) dot = name; - len = strlen (dot) + 8; + len = strlen (dot) + strlen (sname) + 1; rname = (char *) alloca (len); - strcpy (rname, ".rodata"); + strcpy (rname, sname); strcat (rname, dot); - return get_section (rname, SECTION_LINKONCE, decl); + return get_section (rname, (SECTION_LINKONCE | flags), decl); } - /* For .gnu.linkonce.t.foo we want to use .gnu.linkonce.r.foo. */ + /* For .gnu.linkonce.t.foo we want to use .gnu.linkonce.r.foo or + .gnu.linkonce.d.rel.ro.local.foo if the jump table is relocatable. */ else if (DECL_COMDAT_GROUP (decl) && strncmp (name, ".gnu.linkonce.t.", 16) == 0) { - size_t len = strlen (name) + 1; - char *rname = (char *) alloca (len); + size_t len; + char *rname; - memcpy (rname, name, len); - rname[14] = 'r'; - return get_section (rname, SECTION_LINKONCE, decl); + if (relocatable) + { + len = strlen (name) + strlen (".rel.ro.local") + 1; + rname = (char *) alloca (len); + + strcpy (rname, ".gnu.linkonce.d.rel.ro.local"); + strcat (rname, name + 15); + } + else + { + len = strlen (name) + 1; + rname = (char *) alloca (len); + + memcpy (rname, name, len); + rname[14] = 'r'; + } + return get_section (rname, (SECTION_LINKONCE | flags), decl); } /* For .text.foo we want to use .rodata.foo. */ else if (flag_function_sections && flag_data_sections && strncmp (name, ".text.", 6) == 0) { size_t len = strlen (name) + 1; - char *rname = (char *) alloca (len + 2); + char *rname = (char *) alloca (len + strlen (sname) - 5); - memcpy (rname, ".rodata", 7); - memcpy (rname + 7, name + 5, len - 5); - return get_section (rname, 0, decl); + memcpy (rname, sname, strlen (sname)); + memcpy (rname + strlen (sname), name + 5, len - 5); + return get_section (rname, flags, decl); } } - return readonly_data_section; + if (relocatable) + return get_section (sname, flags, decl); + else + return readonly_data_section; } /* Return the read-only data section associated with function DECL @@ -784,7 +840,7 @@ default_function_rodata_section (tree decl) readonly data section. */ section * -default_no_function_rodata_section (tree decl ATTRIBUTE_UNUSED) +default_no_function_rodata_section (tree, bool) { return readonly_data_section; } @@ -794,7 +850,8 @@ default_no_function_rodata_section (tree decl ATTRIBUTE_UNUSED) static const char * function_mergeable_rodata_prefix (void) { - section *s = targetm.asm_out.function_rodata_section (current_function_decl); + section *s = targetm.asm_out.function_rodata_section (current_function_decl, + false); if (SECTION_STYLE (s) == SECTION_NAMED) return s->named.name; else @@ -1019,7 +1076,11 @@ bss_initializer_p (const_tree decl, bool named) || (DECL_INITIAL (decl) == error_mark_node && !in_lto_p) || (flag_zero_initialized_in_bss - && initializer_zerop (DECL_INITIAL (decl))))); + && initializer_zerop (DECL_INITIAL (decl)) + /* A decl with the "persistent" attribute applied and + explicitly initialized to 0 should not be treated as a BSS + variable. */ + && !DECL_PERSISTENT_P (decl)))); } /* Compute the alignment of variable specified by DECL. @@ -1165,7 +1226,8 @@ get_variable_section (tree decl, bool prefer_noswitch_p) if (vnode) vnode->get_constructor (); - if (DECL_COMMON (decl)) + if (DECL_COMMON (decl) + && !(SUPPORTS_SHF_GNU_RETAIN && DECL_PRESERVE_P (decl))) { /* If the decl has been given an explicit section name, or it resides in a non-generic address space, then it isn't common, and shouldn't @@ -1203,6 +1265,7 @@ get_variable_section (tree decl, bool prefer_noswitch_p) if (ADDR_SPACE_GENERIC_P (as) && !DECL_THREAD_LOCAL_P (decl) + && !DECL_NOINIT_P (decl) && !(prefer_noswitch_p && targetm.have_switchable_bss_sections) && bss_initializer_p (decl)) { @@ -1318,6 +1381,23 @@ ultimate_transparent_alias_target (tree *alias) return target; } +/* Return true if REGNUM is mentioned in ELIMINABLE_REGS as a from + register number. */ + +static bool +eliminable_regno_p (int regnum) +{ + static const struct + { + const int from; + const int to; + } eliminables[] = ELIMINABLE_REGS; + for (size_t i = 0; i < ARRAY_SIZE (eliminables); i++) + if (regnum == eliminables[i].from) + return true; + return false; +} + /* Create the DECL_RTL for a VAR_DECL or FUNCTION_DECL. DECL should have static storage duration. In other words, it should not be an automatic variable, including PARM_DECLs. @@ -1420,6 +1500,15 @@ make_decl_rtl (tree decl) else if (!targetm.hard_regno_mode_ok (reg_number, mode)) error ("register specified for %q+D isn%'t suitable for data type", decl); + else if (reg_number != HARD_FRAME_POINTER_REGNUM + && (reg_number == FRAME_POINTER_REGNUM +#ifdef RETURN_ADDRESS_POINTER_REGNUM + || reg_number == RETURN_ADDRESS_POINTER_REGNUM +#endif + || reg_number == ARG_POINTER_REGNUM) + && eliminable_regno_p (reg_number)) + error ("register specified for %q+D is an internal GCC " + "implementation detail", decl); /* Now handle properly declared static register variables. */ else { @@ -1800,7 +1889,7 @@ assemble_start_function (tree decl, const char *fnname) /* Switch to the correct text section for the start of the function. */ - switch_to_section (function_section (decl)); + switch_to_section (function_section (decl), decl); if (crtl->has_bb_partition && !hot_label_written) ASM_OUTPUT_LABEL (asm_out_file, crtl->subsections.hot_section_label); @@ -2296,7 +2385,7 @@ assemble_variable (tree decl, int top_level ATTRIBUTE_UNUSED, && (strcmp (sect->named.name, ".vtable_map_vars") == 0)) handle_vtv_comdat_section (sect, decl); else - switch_to_section (sect); + switch_to_section (sect, decl); if (align > BITS_PER_UNIT) ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (align / BITS_PER_UNIT)); assemble_variable_contents (decl, name, dont_output_data, @@ -6641,6 +6730,9 @@ default_section_type_flags (tree decl, const char *name, int reloc) if (strcmp (name, ".noinit") == 0) flags |= SECTION_WRITE | SECTION_BSS | SECTION_NOTYPE; + if (strcmp (name, ".persistent") == 0) + flags |= SECTION_WRITE | SECTION_NOTYPE; + /* Various sections have special ELF types that the assembler will assign by default based on the name. They are neither SHT_PROGBITS nor SHT_NOBITS, so when changing sections we don't want to print a @@ -6699,9 +6791,10 @@ default_elf_asm_named_section (const char *name, unsigned int flags, /* If we have already declared this section, we can use an abbreviated form to switch back to it -- unless this section is - part of a COMDAT groups, in which case GAS requires the full - declaration every time. */ + part of a COMDAT groups or with SHF_GNU_RETAIN or with SHF_LINK_ORDER, + in which case GAS requires the full declaration every time. */ if (!(HAVE_COMDAT_GROUP && (flags & SECTION_LINKONCE)) + && !(flags & (SECTION_RETAIN | SECTION_LINK_ORDER)) && (flags & SECTION_DECLARED)) { fprintf (asm_out_file, "\t.section\t%s\n", name); @@ -6734,6 +6827,10 @@ default_elf_asm_named_section (const char *name, unsigned int flags, *f++ = TLS_SECTION_ASM_FLAG; if (HAVE_COMDAT_GROUP && (flags & SECTION_LINKONCE)) *f++ = 'G'; + if (flags & SECTION_RETAIN) + *f++ = 'R'; + if (flags & SECTION_LINK_ORDER) + *f++ = 'o'; #ifdef MACH_DEP_SECTION_ASM_FLAG if (flags & SECTION_MACH_DEP) *f++ = MACH_DEP_SECTION_ASM_FLAG; @@ -6766,6 +6863,14 @@ default_elf_asm_named_section (const char *name, unsigned int flags, if (flags & SECTION_ENTSIZE) fprintf (asm_out_file, ",%d", flags & SECTION_ENTSIZE); + if (flags & SECTION_LINK_ORDER) + { + tree id = DECL_ASSEMBLER_NAME (decl); + ultimate_transparent_alias_target (&id); + const char *name = IDENTIFIER_POINTER (id); + name = targetm.strip_name_encoding (name); + fprintf (asm_out_file, ",%s", name); + } if (HAVE_COMDAT_GROUP && (flags & SECTION_LINKONCE)) { if (TREE_CODE (decl) == IDENTIFIER_NODE) @@ -6984,6 +7089,11 @@ default_elf_select_section (tree decl, int reloc, sname = ".sdata2"; break; case SECCAT_DATA: + if (DECL_P (decl) && DECL_PERSISTENT_P (decl)) + { + sname = ".persistent"; + break; + } return data_section; case SECCAT_DATA_REL: sname = ".data.rel"; @@ -7004,13 +7114,11 @@ default_elf_select_section (tree decl, int reloc, sname = ".tdata"; break; case SECCAT_BSS: - if (DECL_P (decl) - && lookup_attribute ("noinit", DECL_ATTRIBUTES (decl)) != NULL_TREE) + if (DECL_P (decl) && DECL_NOINIT_P (decl)) { sname = ".noinit"; break; } - if (bss_section) return bss_section; sname = ".bss"; @@ -7056,6 +7164,11 @@ default_unique_section (tree decl, int reloc) break; case SECCAT_DATA: prefix = one_only ? ".d" : ".data"; + if (DECL_P (decl) && DECL_PERSISTENT_P (decl)) + { + prefix = one_only ? ".p" : ".persistent"; + break; + } break; case SECCAT_DATA_REL: prefix = one_only ? ".d.rel" : ".data.rel"; @@ -7073,6 +7186,11 @@ default_unique_section (tree decl, int reloc) prefix = one_only ? ".s" : ".sdata"; break; case SECCAT_BSS: + if (DECL_P (decl) && DECL_NOINIT_P (decl)) + { + prefix = one_only ? ".n" : ".noinit"; + break; + } prefix = one_only ? ".b" : ".bss"; break; case SECCAT_SBSS: @@ -7634,10 +7752,44 @@ output_section_asm_op (const void *directive) the current section is NEW_SECTION. */ void -switch_to_section (section *new_section) +switch_to_section (section *new_section, tree decl) { if (in_section == new_section) - return; + { + if (SUPPORTS_SHF_GNU_RETAIN + && (new_section->common.flags & SECTION_NAMED) + && decl != nullptr + && DECL_P (decl) + && (!!DECL_PRESERVE_P (decl) + != !!(new_section->common.flags & SECTION_RETAIN))) + { + /* If the SECTION_RETAIN bit doesn't match, switch to a new + section. */ + tree used_decl, no_used_decl; + + if (DECL_PRESERVE_P (decl)) + { + new_section->common.flags |= SECTION_RETAIN; + used_decl = decl; + no_used_decl = new_section->named.decl; + } + else + { + new_section->common.flags &= ~(SECTION_RETAIN + | SECTION_DECLARED); + used_decl = new_section->named.decl; + no_used_decl = decl; + } + warning (OPT_Wattributes, + "%+qD without %<used%> attribute and %qD with " + "%<used%> attribute are placed in a section with " + "the same name", no_used_decl, used_decl); + inform (DECL_SOURCE_LOCATION (used_decl), + "%qD was declared here", used_decl); + } + else + return; + } if (new_section->common.flags & SECTION_FORGET) in_section = NULL; @@ -7975,45 +8127,14 @@ output_object_blocks (void) we want to emit NUL strings terminators into the object file we have to use ASM_OUTPUT_SKIP. */ -int -elf_record_gcc_switches (print_switch_type type, const char * name) +void +elf_record_gcc_switches (const char *options) { - switch (type) - { - case SWITCH_TYPE_PASSED: - ASM_OUTPUT_ASCII (asm_out_file, name, strlen (name)); - ASM_OUTPUT_SKIP (asm_out_file, HOST_WIDE_INT_1U); - break; - - case SWITCH_TYPE_DESCRIPTIVE: - if (name == NULL) - { - /* Distinguish between invocations where name is NULL. */ - static bool started = false; - - if (!started) - { - section * sec; - - sec = get_section (targetm.asm_out.record_gcc_switches_section, - SECTION_DEBUG - | SECTION_MERGE - | SECTION_STRINGS - | (SECTION_ENTSIZE & 1), - NULL); - switch_to_section (sec); - started = true; - } - } - - default: - break; - } - - /* The return value is currently ignored by the caller, but must be 0. - For -fverbose-asm the return value would be the number of characters - emitted into the assembler file. */ - return 0; + section *sec = get_section (targetm.asm_out.record_gcc_switches_section, + SECTION_DEBUG | SECTION_MERGE + | SECTION_STRINGS | (SECTION_ENTSIZE & 1), NULL); + switch_to_section (sec); + ASM_OUTPUT_ASCII (asm_out_file, options, strlen (options) + 1); } /* Emit text to declare externally defined symbols. It is needed to |