X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Fdwarf2expr.h;h=2a92a28908d44e16b4304fd15bb80e21b72bbebb;hb=39f34d7b64ee76e07b82a3e57800905d249d8005;hp=f22d085273da7c22e63d0523e0dd4f2a243b8da1;hpb=87808bd699575a850139a1f916512ab7a47fd496;p=deliverable%2Fbinutils-gdb.git diff --git a/gdb/dwarf2expr.h b/gdb/dwarf2expr.h index f22d085273..2a92a28908 100644 --- a/gdb/dwarf2expr.h +++ b/gdb/dwarf2expr.h @@ -1,11 +1,14 @@ -/* Dwarf2 Expression Evaluator - Copyright 2001, 2002, 2003 Free Software Foundation, Inc. - Contributed by Daniel Berlin (dan@dberlin.org) +/* DWARF 2 Expression Evaluator. + + Copyright (C) 2001-2019 Free Software Foundation, Inc. + + Contributed by Daniel Berlin . + 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 2 of the License, or + 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, @@ -14,75 +17,157 @@ 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, write to the Free Software - Foundation, Inc., 59 Temple Place - Suite 330, - Boston, MA 02111-1307, USA. */ + along with this program. If not, see . */ #if !defined (DWARF2EXPR_H) #define DWARF2EXPR_H -/* The expression evaluator works with a dwarf_expr_context, describing - its current state and its callbacks. */ -struct dwarf_expr_context +#include "leb128.h" +#include "gdbtypes.h" + +/* The location of a value. */ +enum dwarf_value_location { - /* The stack of values, allocated with xmalloc. */ - CORE_ADDR *stack; + /* The piece is in memory. + The value on the dwarf stack is its address. */ + DWARF_VALUE_MEMORY, - /* The number of values currently pushed on the stack, and the - number of elements allocated to the stack. */ - int stack_len, stack_allocated; + /* The piece is in a register. + The value on the dwarf stack is the register number. */ + DWARF_VALUE_REGISTER, - /* An opaque argument provided by the caller, which will be passed - to all of the callback functions. */ - void *baton; + /* The piece is on the dwarf stack. */ + DWARF_VALUE_STACK, - /* Return the value of register number REGNUM. */ - CORE_ADDR (*read_reg) (void *baton, int regnum); + /* The piece is a literal. */ + DWARF_VALUE_LITERAL, - /* Read LENGTH bytes at ADDR into BUF. */ - void (*read_mem) (void *baton, char *buf, CORE_ADDR addr, - size_t length); + /* The piece was optimized out. */ + DWARF_VALUE_OPTIMIZED_OUT, - /* Return the location expression for the frame base attribute, in - START and LENGTH. The result must be live until the current - expression evaluation is complete. */ - void (*get_frame_base) (void *baton, unsigned char **start, - size_t *length); + /* The piece is an implicit pointer. */ + DWARF_VALUE_IMPLICIT_POINTER +}; - /* Return the thread-local storage address for - DW_OP_GNU_push_tls_address. */ - CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset); +/* A piece of an object, as recorded by DW_OP_piece or DW_OP_bit_piece. */ +struct dwarf_expr_piece +{ + enum dwarf_value_location location; -#if 0 - /* Not yet implemented. */ + union + { + struct + { + /* This piece's address, for DWARF_VALUE_MEMORY pieces. */ + CORE_ADDR addr; + /* Non-zero if the piece is known to be in memory and on + the program's stack. */ + bool in_stack_memory; + } mem; - /* Return the location expression for the dwarf expression - subroutine in the die at OFFSET in the current compilation unit. - The result must be live until the current expression evaluation - is complete. */ - unsigned char *(*get_subr) (void *baton, off_t offset, size_t *length); + /* The piece's register number, for DWARF_VALUE_REGISTER pieces. */ + int regno; - /* Return the `object address' for DW_OP_push_object_address. */ - CORE_ADDR (*get_object_address) (void *baton); -#endif + /* The piece's literal value, for DWARF_VALUE_STACK pieces. */ + struct value *value; + + struct + { + /* A pointer to the data making up this piece, + for DWARF_VALUE_LITERAL pieces. */ + const gdb_byte *data; + /* The length of the available data. */ + ULONGEST length; + } literal; + + /* Used for DWARF_VALUE_IMPLICIT_POINTER. */ + struct + { + /* The referent DIE from DW_OP_implicit_pointer. */ + sect_offset die_sect_off; + /* The byte offset into the resulting data. */ + LONGEST offset; + } ptr; + } v; + + /* The length of the piece, in bits. */ + ULONGEST size; + /* The piece offset, in bits. */ + ULONGEST offset; +}; + +/* The dwarf expression stack. */ + +struct dwarf_stack_value +{ + dwarf_stack_value (struct value *value_, int in_stack_memory_) + : value (value_), in_stack_memory (in_stack_memory_) + {} + + struct value *value; + + /* True if the piece is in memory and is known to be on the program's stack. + It is always ok to set this to zero. This is used, for example, to + optimize memory access from the target. It can vastly speed up backtraces + on long latency connections when "set stack-cache on". */ + bool in_stack_memory; +}; + +/* The expression evaluator works with a dwarf_expr_context, describing + its current state and its callbacks. */ +struct dwarf_expr_context +{ + dwarf_expr_context (); + virtual ~dwarf_expr_context () = default; + + void push_address (CORE_ADDR value, bool in_stack_memory); + void eval (const gdb_byte *addr, size_t len); + struct value *fetch (int n); + CORE_ADDR fetch_address (int n); + bool fetch_in_stack_memory (int n); + + /* The stack of values. */ + std::vector stack; + + /* Target architecture to use for address operations. */ + struct gdbarch *gdbarch; + + /* Target address size in bytes. */ + int addr_size; + + /* DW_FORM_ref_addr size in bytes. If -1 DWARF is executed from a frame + context and operations depending on DW_FORM_ref_addr are not allowed. */ + int ref_addr_size; + + /* Offset used to relocate DW_OP_addr, DW_OP_addrx, and + DW_OP_GNU_addr_index arguments. */ + CORE_ADDR offset; /* The current depth of dwarf expression recursion, via DW_OP_call*, DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum depth we'll tolerate before raising an error. */ int recursion_depth, max_recursion_depth; - /* Non-zero if the result is in a register. The register number - will be on the expression stack. */ - int in_reg; + /* Location of the value. */ + enum dwarf_value_location location; + + /* For DWARF_VALUE_LITERAL, the current literal value's length and + data. For DWARF_VALUE_IMPLICIT_POINTER, LEN is the offset of the + target DIE of sect_offset kind. */ + ULONGEST len; + const gdb_byte *data; + + /* Initialization status of variable: Non-zero if variable has been + initialized; zero otherwise. */ + int initialized; - /* An array of pieces. PIECES points to its first element; - NUM_PIECES is its length. + /* A vector of pieces. Each time DW_OP_piece is executed, we add a new element to the end of this array, recording the current top of the stack, the - current in_reg flag, and the size given as the operand to - DW_OP_piece. We then pop the top value from the stack, clear the - in_reg flag, and resume evaluation. + current location, and the size given as the operand to + DW_OP_piece. We then pop the top value from the stack, reset the + location, and resume evaluation. The Dwarf spec doesn't say whether DW_OP_piece pops the top value from the stack. We do, ensuring that clients of this interface @@ -93,47 +178,148 @@ struct dwarf_expr_context If an expression never uses DW_OP_piece, num_pieces will be zero. (It would be nice to present these cases as expressions yielding - a single piece, with in_reg clear, so that callers need not - distinguish between the no-DW_OP_piece and one-DW_OP_piece cases. - But expressions with no DW_OP_piece operations have no value to - place in a piece's 'size' field; the size comes from the - surrounding data. So the two cases need to be handled - separately.) */ - int num_pieces; - struct dwarf_expr_piece *pieces; + a single piece, so that callers need not distinguish between the + no-DW_OP_piece and one-DW_OP_piece cases. But expressions with + no DW_OP_piece operations have no value to place in a piece's + 'size' field; the size comes from the surrounding data. So the + two cases need to be handled separately.) */ + std::vector pieces; + + /* Return the value of register number REGNUM (a DWARF register number), + read as an address. */ + virtual CORE_ADDR read_addr_from_reg (int regnum) = 0; + + /* Return a value of type TYPE, stored in register number REGNUM + of the frame associated to the given BATON. + + REGNUM is a DWARF register number. */ + virtual struct value *get_reg_value (struct type *type, int regnum) = 0; + + /* Read LENGTH bytes at ADDR into BUF. */ + virtual void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t length) = 0; + + /* Return the location expression for the frame base attribute, in + START and LENGTH. The result must be live until the current + expression evaluation is complete. */ + virtual void get_frame_base (const gdb_byte **start, size_t *length) = 0; + + /* Return the CFA for the frame. */ + virtual CORE_ADDR get_frame_cfa () = 0; + + /* Return the PC for the frame. */ + virtual CORE_ADDR get_frame_pc () + { + error (_("%s is invalid in this context"), "DW_OP_implicit_pointer"); + } + + /* Return the thread-local storage address for + DW_OP_GNU_push_tls_address or DW_OP_form_tls_address. */ + virtual CORE_ADDR get_tls_address (CORE_ADDR offset) = 0; + + /* Execute DW_AT_location expression for the DWARF expression + subroutine in the DIE at DIE_CU_OFF in the CU. Do not touch + STACK while it being passed to and returned from the called DWARF + subroutine. */ + virtual void dwarf_call (cu_offset die_cu_off) = 0; + + /* Execute "variable value" operation on the DIE at SECT_OFF. */ + virtual struct value *dwarf_variable_value (sect_offset sect_off) = 0; + + /* Return the base type given by the indicated DIE at DIE_CU_OFF. + This can throw an exception if the DIE is invalid or does not + represent a base type. SIZE is non-zero if this function should + verify that the resulting type has the correct size. */ + virtual struct type *get_base_type (cu_offset die_cu_off, int size) + { + /* Anything will do. */ + return builtin_type (this->gdbarch)->builtin_int; + } + + /* Push on DWARF stack an entry evaluated for DW_TAG_call_site's + parameter matching KIND and KIND_U at the caller of specified BATON. + If DEREF_SIZE is not -1 then use DW_AT_call_data_value instead of + DW_AT_call_value. */ + virtual void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind, + union call_site_parameter_u kind_u, + int deref_size) = 0; + + /* Return the address indexed by DW_OP_addrx or DW_OP_GNU_addr_index. + This can throw an exception if the index is out of range. */ + virtual CORE_ADDR get_addr_index (unsigned int index) = 0; + + /* Return the `object address' for DW_OP_push_object_address. */ + virtual CORE_ADDR get_object_address () = 0; + +private: + + struct type *address_type () const; + void push (struct value *value, bool in_stack_memory); + bool stack_empty_p () const; + void add_piece (ULONGEST size, ULONGEST offset); + void execute_stack_op (const gdb_byte *op_ptr, const gdb_byte *op_end); + void pop (); }; +void dwarf_expr_require_composition (const gdb_byte *, const gdb_byte *, + const char *); -/* A piece of an object, as recorded by DW_OP_piece. */ -struct dwarf_expr_piece +int dwarf_block_to_dwarf_reg (const gdb_byte *buf, const gdb_byte *buf_end); + +int dwarf_block_to_dwarf_reg_deref (const gdb_byte *buf, + const gdb_byte *buf_end, + CORE_ADDR *deref_size_return); + +int dwarf_block_to_fb_offset (const gdb_byte *buf, const gdb_byte *buf_end, + CORE_ADDR *fb_offset_return); + +int dwarf_block_to_sp_offset (struct gdbarch *gdbarch, const gdb_byte *buf, + const gdb_byte *buf_end, + CORE_ADDR *sp_offset_return); + +/* Wrappers around the leb128 reader routines to simplify them for our + purposes. */ + +static inline const gdb_byte * +gdb_read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end, + uint64_t *r) { - /* If IN_REG is zero, then the piece is in memory, and VALUE is its address. - If IN_REG is non-zero, then the piece is in a register, and VALUE - is the register number. */ - int in_reg; + size_t bytes_read = read_uleb128_to_uint64 (buf, buf_end, r); - /* This piece's address or register number. */ - CORE_ADDR value; + if (bytes_read == 0) + return NULL; + return buf + bytes_read; +} - /* The length of the piece, in bytes. */ - ULONGEST size; -}; +static inline const gdb_byte * +gdb_read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end, + int64_t *r) +{ + size_t bytes_read = read_sleb128_to_int64 (buf, buf_end, r); + + if (bytes_read == 0) + return NULL; + return buf + bytes_read; +} + +static inline const gdb_byte * +gdb_skip_leb128 (const gdb_byte *buf, const gdb_byte *buf_end) +{ + size_t bytes_read = skip_leb128 (buf, buf_end); -struct dwarf_expr_context *new_dwarf_expr_context (void); -void free_dwarf_expr_context (struct dwarf_expr_context *ctx); + if (bytes_read == 0) + return NULL; + return buf + bytes_read; +} -void dwarf_expr_push (struct dwarf_expr_context *ctx, CORE_ADDR value); -void dwarf_expr_pop (struct dwarf_expr_context *ctx); -void dwarf_expr_eval (struct dwarf_expr_context *ctx, unsigned char *addr, - size_t len); -CORE_ADDR dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n); +extern const gdb_byte *safe_read_uleb128 (const gdb_byte *buf, + const gdb_byte *buf_end, + uint64_t *r); +extern const gdb_byte *safe_read_sleb128 (const gdb_byte *buf, + const gdb_byte *buf_end, + int64_t *r); -unsigned char *read_uleb128 (unsigned char *buf, unsigned char *buf_end, - ULONGEST * r); -unsigned char *read_sleb128 (unsigned char *buf, unsigned char *buf_end, - LONGEST * r); -CORE_ADDR dwarf2_read_address (unsigned char *buf, unsigned char *buf_end, - int *bytes_read); +extern const gdb_byte *safe_skip_leb128 (const gdb_byte *buf, + const gdb_byte *buf_end); -#endif +#endif /* dwarf2expr.h */