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Diffstat (limited to 'gdb/compile/compile-c-symbols.c')
| -rw-r--r-- | gdb/compile/compile-c-symbols.c | 759 |
1 files changed, 759 insertions, 0 deletions
diff --git a/gdb/compile/compile-c-symbols.c b/gdb/compile/compile-c-symbols.c new file mode 100644 index 0000000..b489c74 --- /dev/null +++ b/gdb/compile/compile-c-symbols.c @@ -0,0 +1,759 @@ +/* Convert symbols from GDB to GCC + + Copyright (C) 2014 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + + +#include "defs.h" +#include "compile-internal.h" +#include "gdb_assert.h" +#include "symtab.h" +#include "parser-defs.h" +#include "block.h" +#include "objfiles.h" +#include "compile.h" +#include "value.h" +#include "exceptions.h" +#include "gdbtypes.h" +#include "dwarf2loc.h" + + + +/* Object of this type are stored in the compiler's symbol_err_map. */ + +struct symbol_error +{ + /* The symbol. */ + + const struct symbol *sym; + + /* The error message to emit. This is malloc'd and owned by the + hash table. */ + + char *message; +}; + +/* Hash function for struct symbol_error. */ + +static hashval_t +hash_symbol_error (const void *a) +{ + const struct symbol_error *se = a; + + return htab_hash_pointer (se->sym); +} + +/* Equality function for struct symbol_error. */ + +static int +eq_symbol_error (const void *a, const void *b) +{ + const struct symbol_error *sea = a; + const struct symbol_error *seb = b; + + return sea->sym == seb->sym; +} + +/* Deletion function for struct symbol_error. */ + +static void +del_symbol_error (void *a) +{ + struct symbol_error *se = a; + + xfree (se->message); + xfree (se); +} + +/* Associate SYMBOL with some error text. */ + +static void +insert_symbol_error (htab_t hash, const struct symbol *sym, const char *text) +{ + struct symbol_error e; + void **slot; + + e.sym = sym; + slot = htab_find_slot (hash, &e, INSERT); + if (*slot == NULL) + { + struct symbol_error *e = XNEW (struct symbol_error); + + e->sym = sym; + e->message = xstrdup (text); + *slot = e; + } +} + +/* Emit the error message corresponding to SYM, if one exists, and + arrange for it not to be emitted again. */ + +static void +error_symbol_once (struct compile_c_instance *context, + const struct symbol *sym) +{ + struct symbol_error search; + struct symbol_error *err; + char *message; + + if (context->symbol_err_map == NULL) + return; + + search.sym = sym; + err = htab_find (context->symbol_err_map, &search); + if (err == NULL || err->message == NULL) + return; + + message = err->message; + err->message = NULL; + make_cleanup (xfree, message); + error (_("%s"), message); +} + + + +/* Compute the name of the pointer representing a local symbol's + address. */ + +static char * +symbol_substitution_name (struct symbol *sym) +{ + return concat ("__", SYMBOL_NATURAL_NAME (sym), "_ptr", (char *) NULL); +} + +/* Convert a given symbol, SYM, to the compiler's representation. + CONTEXT is the compiler instance. IS_GLOBAL is true if the + symbol came from the global scope. IS_LOCAL is true if the symbol + came from a local scope. (Note that the two are not strictly + inverses because the symbol might have come from the static + scope.) */ + +static void +convert_one_symbol (struct compile_c_instance *context, + struct symbol *sym, + int is_global, + int is_local) +{ + gcc_type sym_type; + const char *filename = SYMBOL_SYMTAB (sym)->filename; + unsigned short line = SYMBOL_LINE (sym); + + error_symbol_once (context, sym); + + if (SYMBOL_CLASS (sym) == LOC_LABEL) + sym_type = 0; + else + sym_type = convert_type (context, SYMBOL_TYPE (sym)); + + if (SYMBOL_DOMAIN (sym) == STRUCT_DOMAIN) + { + /* Binding a tag, so we don't need to build a decl. */ + C_CTX (context)->c_ops->tagbind (C_CTX (context), + SYMBOL_NATURAL_NAME (sym), + sym_type, filename, line); + } + else + { + gcc_decl decl; + enum gcc_c_symbol_kind kind; + CORE_ADDR addr = 0; + char *symbol_name = NULL; + + switch (SYMBOL_CLASS (sym)) + { + case LOC_TYPEDEF: + kind = GCC_C_SYMBOL_TYPEDEF; + break; + + case LOC_LABEL: + kind = GCC_C_SYMBOL_LABEL; + addr = SYMBOL_VALUE_ADDRESS (sym); + break; + + case LOC_BLOCK: + kind = GCC_C_SYMBOL_FUNCTION; + addr = BLOCK_START (SYMBOL_BLOCK_VALUE (sym)); + break; + + case LOC_CONST: + if (TYPE_CODE (SYMBOL_TYPE (sym)) == TYPE_CODE_ENUM) + { + /* Already handled by convert_enum. */ + return; + } + C_CTX (context)->c_ops->build_constant (C_CTX (context), sym_type, + SYMBOL_NATURAL_NAME (sym), + SYMBOL_VALUE (sym), + filename, line); + return; + + case LOC_CONST_BYTES: + error (_("Unsupported LOC_CONST_BYTES for symbol \"%s\"."), + SYMBOL_PRINT_NAME (sym)); + + case LOC_UNDEF: + internal_error (__FILE__, __LINE__, _("LOC_UNDEF found for \"%s\"."), + SYMBOL_PRINT_NAME (sym)); + + case LOC_COMMON_BLOCK: + error (_("Fortran common block is unsupported for compilation " + "evaluaton of symbol \"%s\"."), + SYMBOL_PRINT_NAME (sym)); + + case LOC_OPTIMIZED_OUT: + error (_("Symbol \"%s\" cannot be used for compilation evaluation " + "as it is optimized out."), + SYMBOL_PRINT_NAME (sym)); + + case LOC_COMPUTED: + if (is_local) + goto substitution; + /* Probably TLS here. */ + warning (_("Symbol \"%s\" is thread-local and currently can only " + "be referenced from the current thread in " + "compiled code."), + SYMBOL_PRINT_NAME (sym)); + /* FALLTHROUGH */ + case LOC_UNRESOLVED: + /* 'symbol_name' cannot be used here as that one is used only for + local variables from compile_dwarf_expr_to_c. + Global variables can be accessed by GCC only by their address, not + by their name. */ + { + struct value *val; + struct frame_info *frame = NULL; + + if (symbol_read_needs_frame (sym)) + { + frame = get_selected_frame (NULL); + if (frame == NULL) + error (_("Symbol \"%s\" cannot be used because " + "there is no selected frame"), + SYMBOL_PRINT_NAME (sym)); + } + + val = read_var_value (sym, frame); + if (VALUE_LVAL (val) != lval_memory) + error (_("Symbol \"%s\" cannot be used for compilation " + "evaluation as its address has not been found."), + SYMBOL_PRINT_NAME (sym)); + + kind = GCC_C_SYMBOL_VARIABLE; + addr = value_address (val); + } + break; + + + case LOC_REGISTER: + case LOC_ARG: + case LOC_REF_ARG: + case LOC_REGPARM_ADDR: + case LOC_LOCAL: + substitution: + kind = GCC_C_SYMBOL_VARIABLE; + symbol_name = symbol_substitution_name (sym); + break; + + case LOC_STATIC: + kind = GCC_C_SYMBOL_VARIABLE; + addr = SYMBOL_VALUE_ADDRESS (sym); + break; + + case LOC_FINAL_VALUE: + default: + gdb_assert_not_reached ("Unreachable case in convert_one_symbol."); + + } + + /* Don't emit local variable decls for a raw expression. */ + if (context->base.scope != COMPILE_I_RAW_SCOPE + || symbol_name == NULL) + { + decl = C_CTX (context)->c_ops->build_decl (C_CTX (context), + SYMBOL_NATURAL_NAME (sym), + kind, + sym_type, + symbol_name, addr, + filename, line); + + C_CTX (context)->c_ops->bind (C_CTX (context), decl, is_global); + } + + xfree (symbol_name); + } +} + +/* Convert a full symbol to its gcc form. CONTEXT is the compiler to + use, IDENTIFIER is the name of the symbol, SYM is the symbol + itself, and DOMAIN is the domain which was searched. */ + +static void +convert_symbol_sym (struct compile_c_instance *context, const char *identifier, + struct symbol *sym, domain_enum domain) +{ + const struct block *static_block, *found_block; + int is_local_symbol; + + found_block = block_found; + + /* If we found a symbol and it is not in the static or global + scope, then we should first convert any static or global scope + symbol of the same name. This lets this unusual case work: + + int x; // Global. + int func(void) + { + int x; + // At this spot, evaluate "extern int x; x" + } + */ + + static_block = block_static_block (found_block); + /* STATIC_BLOCK is NULL if FOUND_BLOCK is the global block. */ + is_local_symbol = (found_block != static_block && static_block != NULL); + if (is_local_symbol) + { + struct symbol *global_sym; + + global_sym = lookup_symbol (identifier, NULL, domain, NULL); + /* If the outer symbol is in the static block, we ignore it, as + it cannot be referenced. */ + if (global_sym != NULL + && block_found != block_static_block (block_found)) + { + if (compile_debug) + fprintf_unfiltered (gdb_stdout, + "gcc_convert_symbol \"%s\": global symbol\n", + identifier); + convert_one_symbol (context, global_sym, 1, 0); + } + } + + if (compile_debug) + fprintf_unfiltered (gdb_stdout, + "gcc_convert_symbol \"%s\": local symbol\n", + identifier); + convert_one_symbol (context, sym, 0, is_local_symbol); +} + +/* Convert a minimal symbol to its gcc form. CONTEXT is the compiler + to use and BMSYM is the minimal symbol to convert. */ + +static void +convert_symbol_bmsym (struct compile_c_instance *context, + struct bound_minimal_symbol bmsym) +{ + struct minimal_symbol *msym = bmsym.minsym; + struct objfile *objfile = bmsym.objfile; + struct type *type; + enum gcc_c_symbol_kind kind; + gcc_type sym_type; + gcc_decl decl; + CORE_ADDR addr; + + /* Conversion copied from write_exp_msymbol. */ + switch (MSYMBOL_TYPE (msym)) + { + case mst_text: + case mst_file_text: + case mst_solib_trampoline: + type = objfile_type (objfile)->nodebug_text_symbol; + kind = GCC_C_SYMBOL_FUNCTION; + break; + + case mst_text_gnu_ifunc: + type = objfile_type (objfile)->nodebug_text_gnu_ifunc_symbol; + kind = GCC_C_SYMBOL_FUNCTION; + break; + + case mst_data: + case mst_file_data: + case mst_bss: + case mst_file_bss: + type = objfile_type (objfile)->nodebug_data_symbol; + kind = GCC_C_SYMBOL_VARIABLE; + break; + + case mst_slot_got_plt: + type = objfile_type (objfile)->nodebug_got_plt_symbol; + kind = GCC_C_SYMBOL_FUNCTION; + break; + + default: + type = objfile_type (objfile)->nodebug_unknown_symbol; + kind = GCC_C_SYMBOL_VARIABLE; + break; + } + + sym_type = convert_type (context, type); + addr = MSYMBOL_VALUE_ADDRESS (objfile, msym); + decl = C_CTX (context)->c_ops->build_decl (C_CTX (context), + MSYMBOL_NATURAL_NAME (msym), + kind, sym_type, NULL, addr, + NULL, 0); + C_CTX (context)->c_ops->bind (C_CTX (context), decl, 1 /* is_global */); +} + +/* See compile-internal.h. */ + +void +gcc_convert_symbol (void *datum, + struct gcc_c_context *gcc_context, + enum gcc_c_oracle_request request, + const char *identifier) +{ + struct compile_c_instance *context = datum; + domain_enum domain; + volatile struct gdb_exception e; + int found = 0; + + switch (request) + { + case GCC_C_ORACLE_SYMBOL: + domain = VAR_DOMAIN; + break; + case GCC_C_ORACLE_TAG: + domain = STRUCT_DOMAIN; + break; + case GCC_C_ORACLE_LABEL: + domain = LABEL_DOMAIN; + break; + default: + gdb_assert_not_reached ("Unrecognized oracle request."); + } + + /* We can't allow exceptions to escape out of this callback. Safest + is to simply emit a gcc error. */ + TRY_CATCH (e, RETURN_MASK_ALL) + { + struct symbol *sym; + + sym = lookup_symbol (identifier, context->base.block, domain, NULL); + if (sym != NULL) + { + convert_symbol_sym (context, identifier, sym, domain); + found = 1; + } + else if (domain == VAR_DOMAIN) + { + struct bound_minimal_symbol bmsym; + + bmsym = lookup_minimal_symbol (identifier, NULL, NULL); + if (bmsym.minsym != NULL) + { + convert_symbol_bmsym (context, bmsym); + found = 1; + } + } + } + + if (e.reason < 0) + C_CTX (context)->c_ops->error (C_CTX (context), e.message); + + if (compile_debug && !found) + fprintf_unfiltered (gdb_stdout, + "gcc_convert_symbol \"%s\": lookup_symbol failed\n", + identifier); + return; +} + +/* See compile-internal.h. */ + +gcc_address +gcc_symbol_address (void *datum, struct gcc_c_context *gcc_context, + const char *identifier) +{ + struct compile_c_instance *context = datum; + volatile struct gdb_exception e; + gcc_address result = 0; + int found = 0; + + /* We can't allow exceptions to escape out of this callback. Safest + is to simply emit a gcc error. */ + TRY_CATCH (e, RETURN_MASK_ERROR) + { + struct symbol *sym; + + /* We only need global functions here. */ + sym = lookup_symbol (identifier, NULL, VAR_DOMAIN, NULL); + if (sym != NULL && SYMBOL_CLASS (sym) == LOC_BLOCK) + { + if (compile_debug) + fprintf_unfiltered (gdb_stdout, + "gcc_symbol_address \"%s\": full symbol\n", + identifier); + result = BLOCK_START (SYMBOL_BLOCK_VALUE (sym)); + found = 1; + } + else + { + struct bound_minimal_symbol msym; + + msym = lookup_bound_minimal_symbol (identifier); + if (msym.minsym != NULL) + { + if (compile_debug) + fprintf_unfiltered (gdb_stdout, + "gcc_symbol_address \"%s\": minimal " + "symbol\n", + identifier); + result = BMSYMBOL_VALUE_ADDRESS (msym); + found = 1; + } + } + } + + if (e.reason < 0) + C_CTX (context)->c_ops->error (C_CTX (context), e.message); + + if (compile_debug && !found) + fprintf_unfiltered (gdb_stdout, + "gcc_symbol_address \"%s\": failed\n", + identifier); + return result; +} + + + +/* A hash function for symbol names. */ + +static hashval_t +hash_symname (const void *a) +{ + const struct symbol *sym = a; + + return htab_hash_string (SYMBOL_NATURAL_NAME (sym)); +} + +/* A comparison function for hash tables that just looks at symbol + names. */ + +static int +eq_symname (const void *a, const void *b) +{ + const struct symbol *syma = a; + const struct symbol *symb = b; + + return strcmp (SYMBOL_NATURAL_NAME (syma), SYMBOL_NATURAL_NAME (symb)) == 0; +} + +/* If a symbol with the same name as SYM is already in HASHTAB, return + 1. Otherwise, add SYM to HASHTAB and return 0. */ + +static int +symbol_seen (htab_t hashtab, struct symbol *sym) +{ + void **slot; + + slot = htab_find_slot (hashtab, sym, INSERT); + if (*slot != NULL) + return 1; + + *slot = sym; + return 0; +} + +/* Generate C code to compute the length of a VLA. */ + +static void +generate_vla_size (struct compile_c_instance *compiler, + struct ui_file *stream, + struct gdbarch *gdbarch, + unsigned char *registers_used, + CORE_ADDR pc, + struct type *type, + struct symbol *sym) +{ + type = check_typedef (type); + + if (TYPE_CODE (type) == TYPE_CODE_REF) + type = check_typedef (TYPE_TARGET_TYPE (type)); + + switch (TYPE_CODE (type)) + { + case TYPE_CODE_RANGE: + { + if (TYPE_HIGH_BOUND_KIND (type) == PROP_LOCEXPR + || TYPE_HIGH_BOUND_KIND (type) == PROP_LOCLIST) + { + const struct dynamic_prop *prop = &TYPE_RANGE_DATA (type)->high; + char *name = c_get_range_decl_name (prop); + struct cleanup *cleanup = make_cleanup (xfree, name); + + dwarf2_compile_property_to_c (stream, name, + gdbarch, registers_used, + prop, pc, sym); + do_cleanups (cleanup); + } + } + break; + + case TYPE_CODE_ARRAY: + generate_vla_size (compiler, stream, gdbarch, registers_used, pc, + TYPE_INDEX_TYPE (type), sym); + generate_vla_size (compiler, stream, gdbarch, registers_used, pc, + TYPE_TARGET_TYPE (type), sym); + break; + + case TYPE_CODE_UNION: + case TYPE_CODE_STRUCT: + { + int i; + + for (i = 0; i < TYPE_NFIELDS (type); ++i) + if (!field_is_static (&TYPE_FIELD (type, i))) + generate_vla_size (compiler, stream, gdbarch, registers_used, pc, + TYPE_FIELD_TYPE (type, i), sym); + } + break; + } +} + +/* Generate C code to compute the address of SYM. */ + +static void +generate_c_for_for_one_variable (struct compile_c_instance *compiler, + struct ui_file *stream, + struct gdbarch *gdbarch, + unsigned char *registers_used, + CORE_ADDR pc, + struct symbol *sym) +{ + volatile struct gdb_exception e; + + TRY_CATCH (e, RETURN_MASK_ERROR) + { + if (is_dynamic_type (SYMBOL_TYPE (sym))) + { + struct ui_file *size_file = mem_fileopen (); + struct cleanup *cleanup = make_cleanup_ui_file_delete (size_file); + + generate_vla_size (compiler, size_file, gdbarch, registers_used, pc, + SYMBOL_TYPE (sym), sym); + ui_file_put (size_file, ui_file_write_for_put, stream); + + do_cleanups (cleanup); + } + + if (SYMBOL_COMPUTED_OPS (sym) != NULL) + { + char *generated_name = symbol_substitution_name (sym); + struct cleanup *cleanup = make_cleanup (xfree, generated_name); + /* We need to emit to a temporary buffer in case an error + occurs in the middle. */ + struct ui_file *local_file = mem_fileopen (); + + make_cleanup_ui_file_delete (local_file); + SYMBOL_COMPUTED_OPS (sym)->generate_c_location (sym, local_file, + gdbarch, + registers_used, + pc, generated_name); + ui_file_put (local_file, ui_file_write_for_put, stream); + + do_cleanups (cleanup); + } + else + { + switch (SYMBOL_CLASS (sym)) + { + case LOC_REGISTER: + case LOC_ARG: + case LOC_REF_ARG: + case LOC_REGPARM_ADDR: + case LOC_LOCAL: + error (_("Local symbol unhandled when generating C code.")); + + case LOC_COMPUTED: + gdb_assert_not_reached (_("LOC_COMPUTED variable " + "missing a method.")); + + default: + /* Nothing to do for all other cases, as they don't represent + local variables. */ + break; + } + } + } + + if (e.reason >= 0) + return; + + if (compiler->symbol_err_map == NULL) + compiler->symbol_err_map = htab_create_alloc (10, + hash_symbol_error, + eq_symbol_error, + del_symbol_error, + xcalloc, + xfree); + insert_symbol_error (compiler->symbol_err_map, sym, e.message); +} + +/* See compile-internal.h. */ + +unsigned char * +generate_c_for_variable_locations (struct compile_c_instance *compiler, + struct ui_file *stream, + struct gdbarch *gdbarch, + const struct block *block, + CORE_ADDR pc) +{ + struct cleanup *cleanup, *outer; + htab_t symhash; + const struct block *static_block = block_static_block (block); + unsigned char *registers_used; + + /* If we're already in the static or global block, there is nothing + to write. */ + if (static_block == NULL || block == static_block) + return NULL; + + registers_used = XCNEWVEC (unsigned char, gdbarch_num_regs (gdbarch)); + outer = make_cleanup (xfree, registers_used); + + /* Ensure that a given name is only entered once. This reflects the + reality of shadowing. */ + symhash = htab_create_alloc (1, hash_symname, eq_symname, NULL, + xcalloc, xfree); + cleanup = make_cleanup_htab_delete (symhash); + + while (1) + { + struct symbol *sym; + struct block_iterator iter; + + /* Iterate over symbols in this block, generating code to + compute the location of each local variable. */ + for (sym = block_iterator_first (block, &iter); + sym != NULL; + sym = block_iterator_next (&iter)) + { + if (!symbol_seen (symhash, sym)) + generate_c_for_for_one_variable (compiler, stream, gdbarch, + registers_used, pc, sym); + } + + /* If we just finished the outermost block of a function, we're + done. */ + if (BLOCK_FUNCTION (block) != NULL) + break; + block = BLOCK_SUPERBLOCK (block); + } + + do_cleanups (cleanup); + discard_cleanups (outer); + return registers_used; +} |