/* DWARF 2 Expression Evaluator.
- Copyright (C) 2001, 2002, 2003, 2005, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2001-2020 Free Software Foundation, Inc.
Contributed by Daniel Berlin <dan@dberlin.org>.
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,
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., 51 Franklin Street, Fifth Floor,
- Boston, MA 02110-1301, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#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, gdb_byte *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, gdb_byte **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;
+
+ 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;
+
+ /* The piece's register number, for DWARF_VALUE_REGISTER pieces. */
+ int regno;
+
+ /* 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. */
-#if 0
- /* Not yet implemented. */
+struct dwarf_stack_value
+{
+ dwarf_stack_value (struct value *value_, int in_stack_memory_)
+ : value (value_), in_stack_memory (in_stack_memory_)
+ {}
- /* 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);
+ struct value *value;
- /* Return the `object address' for DW_OP_push_object_address. */
- CORE_ADDR (*get_object_address) (void *baton);
-#endif
+ /* 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<dwarf_stack_value> 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;
- /* An array of pieces. PIECES points to its first element;
- NUM_PIECES is its length.
+ /* Initialization status of variable: Non-zero if variable has been
+ initialized; zero otherwise. */
+ int initialized;
+
+ /* 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
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<dwarf_expr_piece> 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);
-gdb_byte *read_uleb128 (gdb_byte *buf, gdb_byte *buf_end, ULONGEST * r);
-gdb_byte *read_sleb128 (gdb_byte *buf, gdb_byte *buf_end, LONGEST * r);
-CORE_ADDR dwarf2_read_address (gdb_byte *buf, gdb_byte *buf_end,
- int *bytes_read);
+extern const gdb_byte *safe_skip_leb128 (const gdb_byte *buf,
+ const gdb_byte *buf_end);
#endif /* dwarf2expr.h */
projects / deliverable / binutils-gdb.git / blobdiff