490 lines
14 KiB
C
490 lines
14 KiB
C
/* Convert symbols from GDB to GCC
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Copyright (C) 2014-2020 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "compile-internal.h"
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#include "compile-cplus.h"
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#include "gdbsupport/gdb_assert.h"
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#include "symtab.h"
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#include "parser-defs.h"
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#include "block.h"
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#include "objfiles.h"
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#include "compile.h"
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#include "value.h"
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#include "exceptions.h"
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#include "gdbtypes.h"
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#include "dwarf2loc.h"
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#include "cp-support.h"
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#include "gdbcmd.h"
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#include "compile-c.h"
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/* Convert a given symbol, SYM, to the compiler's representation.
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INSTANCE is the compiler instance. IS_GLOBAL is true if the
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symbol came from the global scope. IS_LOCAL is true if the symbol
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came from a local scope. (Note that the two are not strictly
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inverses because the symbol might have come from the static
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scope.) */
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static void
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convert_one_symbol (compile_cplus_instance *instance,
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struct block_symbol sym, bool is_global, bool is_local)
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{
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/* Squash compiler warning. */
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gcc_type sym_type = 0;
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const char *filename = symbol_symtab (sym.symbol)->filename;
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unsigned short line = SYMBOL_LINE (sym.symbol);
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instance->error_symbol_once (sym.symbol);
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if (SYMBOL_CLASS (sym.symbol) == LOC_LABEL)
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sym_type = 0;
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else
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sym_type = instance->convert_type (SYMBOL_TYPE (sym.symbol));
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if (SYMBOL_DOMAIN (sym.symbol) == STRUCT_DOMAIN)
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{
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/* Nothing to do. */
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}
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else
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{
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/* Squash compiler warning. */
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gcc_cp_symbol_kind_flags kind = GCC_CP_FLAG_BASE;
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CORE_ADDR addr = 0;
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std::string name;
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gdb::unique_xmalloc_ptr<char> symbol_name;
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switch (SYMBOL_CLASS (sym.symbol))
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{
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case LOC_TYPEDEF:
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if (TYPE_CODE (SYMBOL_TYPE (sym.symbol)) == TYPE_CODE_TYPEDEF)
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kind = GCC_CP_SYMBOL_TYPEDEF;
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else if (TYPE_CODE (SYMBOL_TYPE (sym.symbol)) == TYPE_CODE_NAMESPACE)
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return;
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break;
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case LOC_LABEL:
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kind = GCC_CP_SYMBOL_LABEL;
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addr = SYMBOL_VALUE_ADDRESS (sym.symbol);
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break;
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case LOC_BLOCK:
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{
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kind = GCC_CP_SYMBOL_FUNCTION;
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addr = BLOCK_START (SYMBOL_BLOCK_VALUE (sym.symbol));
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if (is_global && TYPE_GNU_IFUNC (SYMBOL_TYPE (sym.symbol)))
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addr = gnu_ifunc_resolve_addr (target_gdbarch (), addr);
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}
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break;
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case LOC_CONST:
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if (TYPE_CODE (SYMBOL_TYPE (sym.symbol)) == TYPE_CODE_ENUM)
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{
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/* Already handled by convert_enum. */
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return;
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}
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instance->plugin ().build_constant
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(sym_type, sym.symbol->natural_name (),
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SYMBOL_VALUE (sym.symbol), filename, line);
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return;
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case LOC_CONST_BYTES:
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error (_("Unsupported LOC_CONST_BYTES for symbol \"%s\"."),
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sym.symbol->print_name ());
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case LOC_UNDEF:
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internal_error (__FILE__, __LINE__, _("LOC_UNDEF found for \"%s\"."),
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sym.symbol->print_name ());
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case LOC_COMMON_BLOCK:
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error (_("Fortran common block is unsupported for compilation "
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"evaluaton of symbol \"%s\"."),
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sym.symbol->print_name ());
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case LOC_OPTIMIZED_OUT:
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error (_("Symbol \"%s\" cannot be used for compilation evaluation "
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"as it is optimized out."),
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sym.symbol->print_name ());
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case LOC_COMPUTED:
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if (is_local)
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goto substitution;
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/* Probably TLS here. */
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warning (_("Symbol \"%s\" is thread-local and currently can only "
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"be referenced from the current thread in "
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"compiled code."),
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sym.symbol->print_name ());
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/* FALLTHROUGH */
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case LOC_UNRESOLVED:
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/* 'symbol_name' cannot be used here as that one is used only for
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local variables from compile_dwarf_expr_to_c.
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Global variables can be accessed by GCC only by their address, not
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by their name. */
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{
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struct value *val;
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struct frame_info *frame = nullptr;
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if (symbol_read_needs_frame (sym.symbol))
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{
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frame = get_selected_frame (nullptr);
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if (frame == nullptr)
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error (_("Symbol \"%s\" cannot be used because "
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"there is no selected frame"),
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sym.symbol->print_name ());
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}
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val = read_var_value (sym.symbol, sym.block, frame);
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if (VALUE_LVAL (val) != lval_memory)
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error (_("Symbol \"%s\" cannot be used for compilation "
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"evaluation as its address has not been found."),
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sym.symbol->print_name ());
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kind = GCC_CP_SYMBOL_VARIABLE;
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addr = value_address (val);
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}
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break;
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case LOC_REGISTER:
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case LOC_ARG:
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case LOC_REF_ARG:
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case LOC_REGPARM_ADDR:
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case LOC_LOCAL:
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substitution:
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kind = GCC_CP_SYMBOL_VARIABLE;
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symbol_name = c_symbol_substitution_name (sym.symbol);
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break;
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case LOC_STATIC:
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kind = GCC_CP_SYMBOL_VARIABLE;
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addr = SYMBOL_VALUE_ADDRESS (sym.symbol);
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break;
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case LOC_FINAL_VALUE:
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default:
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gdb_assert_not_reached ("Unreachable case in convert_one_symbol.");
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}
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/* Don't emit local variable decls for a raw expression. */
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if (instance->scope () != COMPILE_I_RAW_SCOPE || symbol_name == nullptr)
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{
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/* For non-local symbols, create/push a new scope so that the
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symbol is properly scoped to the plug-in. */
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if (!is_local)
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{
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compile_scope scope
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= instance->new_scope (sym.symbol->natural_name (),
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SYMBOL_TYPE (sym.symbol));
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if (scope.nested_type () != GCC_TYPE_NONE)
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{
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/* We found a symbol for this type that was defined inside
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some other symbol, e.g., a class typedef defined. */
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return;
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}
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instance->enter_scope (std::move (scope));
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}
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/* Get the `raw' name of the symbol. */
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if (name.empty () && sym.symbol->natural_name () != nullptr)
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name = compile_cplus_instance::decl_name
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(sym.symbol->natural_name ()).get ();
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/* Define the decl. */
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instance->plugin ().build_decl
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("variable", name.c_str (), kind, sym_type,
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symbol_name.get (), addr, filename, line);
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/* Pop scope for non-local symbols. */
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if (!is_local)
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instance->leave_scope ();
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}
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}
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}
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/* Convert a full symbol to its gcc form. CONTEXT is the compiler to
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use, IDENTIFIER is the name of the symbol, SYM is the symbol
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itself, and DOMAIN is the domain which was searched. */
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static void
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convert_symbol_sym (compile_cplus_instance *instance,
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const char *identifier, struct block_symbol sym,
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domain_enum domain)
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{
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/* If we found a symbol and it is not in the static or global
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scope, then we should first convert any static or global scope
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symbol of the same name. This lets this unusual case work:
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int x; // Global.
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int func(void)
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{
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int x;
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// At this spot, evaluate "extern int x; x"
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}
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*/
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const struct block *static_block = block_static_block (sym.block);
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/* STATIC_BLOCK is NULL if FOUND_BLOCK is the global block. */
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bool is_local_symbol = (sym.block != static_block && static_block != nullptr);
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if (is_local_symbol)
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{
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struct block_symbol global_sym;
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global_sym = lookup_symbol (identifier, nullptr, domain, nullptr);
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/* If the outer symbol is in the static block, we ignore it, as
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it cannot be referenced. */
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if (global_sym.symbol != nullptr
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&& global_sym.block != block_static_block (global_sym.block))
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{
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if (compile_debug)
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fprintf_unfiltered (gdb_stdlog,
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"gcc_convert_symbol \"%s\": global symbol\n",
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identifier);
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convert_one_symbol (instance, global_sym, true, false);
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}
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}
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if (compile_debug)
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fprintf_unfiltered (gdb_stdlog,
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"gcc_convert_symbol \"%s\": local symbol\n",
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identifier);
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convert_one_symbol (instance, sym, false, is_local_symbol);
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}
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/* Convert a minimal symbol to its gcc form. CONTEXT is the compiler
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to use and BMSYM is the minimal symbol to convert. */
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static void
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convert_symbol_bmsym (compile_cplus_instance *instance,
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struct bound_minimal_symbol bmsym)
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{
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struct minimal_symbol *msym = bmsym.minsym;
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struct objfile *objfile = bmsym.objfile;
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struct type *type;
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gcc_cp_symbol_kind_flags kind;
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gcc_type sym_type;
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CORE_ADDR addr;
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addr = MSYMBOL_VALUE_ADDRESS (objfile, msym);
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/* Conversion copied from write_exp_msymbol. */
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switch (MSYMBOL_TYPE (msym))
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{
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case mst_text:
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case mst_file_text:
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case mst_solib_trampoline:
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type = objfile_type (objfile)->nodebug_text_symbol;
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kind = GCC_CP_SYMBOL_FUNCTION;
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break;
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case mst_text_gnu_ifunc:
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/* nodebug_text_gnu_ifunc_symbol would cause:
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function return type cannot be function */
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type = objfile_type (objfile)->nodebug_text_symbol;
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kind = GCC_CP_SYMBOL_FUNCTION;
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addr = gnu_ifunc_resolve_addr (target_gdbarch (), addr);
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break;
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case mst_data:
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case mst_file_data:
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case mst_bss:
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case mst_file_bss:
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type = objfile_type (objfile)->nodebug_data_symbol;
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kind = GCC_CP_SYMBOL_VARIABLE;
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break;
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case mst_slot_got_plt:
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type = objfile_type (objfile)->nodebug_got_plt_symbol;
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kind = GCC_CP_SYMBOL_FUNCTION;
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break;
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default:
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type = objfile_type (objfile)->nodebug_unknown_symbol;
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kind = GCC_CP_SYMBOL_VARIABLE;
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break;
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}
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sym_type = instance->convert_type (type);
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instance->plugin ().push_namespace ("");
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instance->plugin ().build_decl
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("minsym", msym->natural_name (), kind, sym_type, nullptr, addr,
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nullptr, 0);
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instance->plugin ().pop_binding_level ("");
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}
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/* See compile-cplus.h. */
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void
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gcc_cplus_convert_symbol (void *datum,
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struct gcc_cp_context *gcc_context,
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enum gcc_cp_oracle_request request,
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const char *identifier)
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{
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if (compile_debug)
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fprintf_unfiltered (gdb_stdlog,
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"got oracle request for \"%s\"\n", identifier);
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bool found = false;
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compile_cplus_instance *instance = (compile_cplus_instance *) datum;
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try
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{
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/* Symbol searching is a three part process unfortunately. */
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/* First do a "standard" lookup, converting any found symbols.
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This will find variables in the current scope. */
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struct block_symbol sym
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= lookup_symbol (identifier, instance->block (), VAR_DOMAIN, nullptr);
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if (sym.symbol != nullptr)
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{
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found = true;
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convert_symbol_sym (instance, identifier, sym, VAR_DOMAIN);
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}
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/* Then use linespec.c's multi-symbol search. This should find
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all non-variable symbols for which we have debug info. */
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symbol_searcher searcher;
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searcher.find_all_symbols (identifier, current_language,
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ALL_DOMAIN, nullptr, nullptr);
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/* Convert any found symbols. */
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for (const auto &it : searcher.matching_symbols ())
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{
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/* Don't convert the symbol found above, if any, twice! */
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if (it.symbol != sym.symbol)
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{
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found = true;
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convert_symbol_sym (instance, identifier, it,
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SYMBOL_DOMAIN (it.symbol));
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}
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}
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/* Finally, if no symbols have been found, fall back to minsyms. */
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if (!found)
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{
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for (const auto &it : searcher.matching_msymbols ())
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{
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found = true;
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convert_symbol_bmsym (instance, it);
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}
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}
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}
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catch (const gdb_exception &e)
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{
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/* We can't allow exceptions to escape out of this callback. Safest
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is to simply emit a gcc error. */
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instance->plugin ().error (e.what ());
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}
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if (compile_debug && !found)
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fprintf_unfiltered (gdb_stdlog,
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"gcc_convert_symbol \"%s\": lookup_symbol failed\n",
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identifier);
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if (compile_debug)
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{
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if (found)
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fprintf_unfiltered (gdb_stdlog, "found type for %s\n", identifier);
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else
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{
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fprintf_unfiltered (gdb_stdlog, "did not find type for %s\n",
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identifier);
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}
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}
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return;
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}
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/* See compile-cplus.h. */
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gcc_address
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gcc_cplus_symbol_address (void *datum, struct gcc_cp_context *gcc_context,
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const char *identifier)
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{
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compile_cplus_instance *instance = (compile_cplus_instance *) datum;
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gcc_address result = 0;
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int found = 0;
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if (compile_debug)
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fprintf_unfiltered (gdb_stdlog,
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"got oracle request for address of %s\n", identifier);
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/* We can't allow exceptions to escape out of this callback. Safest
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is to simply emit a gcc error. */
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try
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{
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struct symbol *sym
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= lookup_symbol (identifier, nullptr, VAR_DOMAIN, nullptr).symbol;
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if (sym != nullptr && SYMBOL_CLASS (sym) == LOC_BLOCK)
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{
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if (compile_debug)
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fprintf_unfiltered (gdb_stdlog,
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"gcc_symbol_address \"%s\": full symbol\n",
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identifier);
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result = BLOCK_START (SYMBOL_BLOCK_VALUE (sym));
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if (TYPE_GNU_IFUNC (SYMBOL_TYPE (sym)))
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result = gnu_ifunc_resolve_addr (target_gdbarch (), result);
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found = 1;
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}
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else
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{
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struct bound_minimal_symbol msym;
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msym = lookup_bound_minimal_symbol (identifier);
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if (msym.minsym != nullptr)
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{
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if (compile_debug)
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fprintf_unfiltered (gdb_stdlog,
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"gcc_symbol_address \"%s\": minimal "
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"symbol\n",
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identifier);
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result = BMSYMBOL_VALUE_ADDRESS (msym);
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if (MSYMBOL_TYPE (msym.minsym) == mst_text_gnu_ifunc)
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result = gnu_ifunc_resolve_addr (target_gdbarch (), result);
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found = 1;
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}
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}
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}
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catch (const gdb_exception_error &e)
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{
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instance->plugin ().error (e.what ());
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}
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if (compile_debug && !found)
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fprintf_unfiltered (gdb_stdlog,
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"gcc_symbol_address \"%s\": failed\n",
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identifier);
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if (compile_debug)
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{
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if (found)
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fprintf_unfiltered (gdb_stdlog, "found address for %s!\n", identifier);
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else
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fprintf_unfiltered (gdb_stdlog,
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"did not find address for %s\n", identifier);
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}
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return result;
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}
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