/* DWARF 2 Expression Evaluator.
- Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008
- Free Software Foundation, Inc.
+ Copyright (C) 2001-2016 Free Software Foundation, Inc.
Contributed by Daniel Berlin <dan@dberlin.org>.
#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
-{
- /* The stack of values, allocated with xmalloc. */
- CORE_ADDR *stack;
+#include "leb128.h"
+#include "gdbtypes.h"
- /* The number of values currently pushed on the stack, and the
- number of elements allocated to the stack. */
- int stack_len, stack_allocated;
+struct dwarf_expr_context;
- /* Target address size in bytes. */
- int addr_size;
+/* Virtual method table for struct dwarf_expr_context below. */
- /* An opaque argument provided by the caller, which will be passed
- to all of the callback functions. */
- void *baton;
+struct dwarf_expr_context_funcs
+{
+ /* Return the value of register number REGNUM (a DWARF register number),
+ read as an address. */
+ CORE_ADDR (*read_addr_from_reg) (void *baton, int regnum);
- /* Return the value of register number REGNUM. */
- CORE_ADDR (*read_reg) (void *baton, int regnum);
+ /* 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. */
+ struct value *(*get_reg_value) (void *baton, struct type *type, int regnum);
/* Read LENGTH bytes at ADDR into BUF. */
void (*read_mem) (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t length);
/* 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);
+ void (*get_frame_base) (void *baton, const gdb_byte **start, size_t *length);
+
+ /* Return the CFA for the frame. */
+ CORE_ADDR (*get_frame_cfa) (void *baton);
+
+ /* Return the PC for the frame. */
+ CORE_ADDR (*get_frame_pc) (void *baton);
/* Return the thread-local storage address for
DW_OP_GNU_push_tls_address. */
CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset);
-#if 0
- /* Not yet implemented. */
-
- /* 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);
+ /* Execute DW_AT_location expression for the DWARF expression subroutine in
+ the DIE at DIE_OFFSET in the CU from CTX. Do not touch STACK while it
+ being passed to and returned from the called DWARF subroutine. */
+ void (*dwarf_call) (struct dwarf_expr_context *ctx, cu_offset die_offset);
+
+ /* Return the base type given by the indicated DIE. This can throw
+ an exception if the DIE is invalid or does not represent a base
+ type. If can also be NULL in the special case where the
+ callbacks are not performing evaluation, and thus it is
+ meaningful to substitute a stub type of the correct size. */
+ struct type *(*get_base_type) (struct dwarf_expr_context *ctx, cu_offset die);
+
+ /* Push on DWARF stack an entry evaluated for DW_TAG_GNU_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_GNU_call_site_data_value instead of
+ DW_AT_GNU_call_site_value. */
+ void (*push_dwarf_reg_entry_value) (struct dwarf_expr_context *ctx,
+ enum call_site_parameter_kind kind,
+ union call_site_parameter_u kind_u,
+ int deref_size);
+
+ /* Return the address indexed by DW_OP_GNU_addr_index.
+ This can throw an exception if the index is out of range. */
+ CORE_ADDR (*get_addr_index) (void *baton, unsigned int index);
/* Return the `object address' for DW_OP_push_object_address. */
CORE_ADDR (*get_object_address) (void *baton);
-#endif
+};
+
+/* The location of a value. */
+enum dwarf_value_location
+{
+ /* The piece is in memory.
+ The value on the dwarf stack is its address. */
+ DWARF_VALUE_MEMORY,
+
+ /* The piece is in a register.
+ The value on the dwarf stack is the register number. */
+ DWARF_VALUE_REGISTER,
+
+ /* The piece is on the dwarf stack. */
+ DWARF_VALUE_STACK,
+
+ /* The piece is a literal. */
+ DWARF_VALUE_LITERAL,
+
+ /* The piece was optimized out. */
+ DWARF_VALUE_OPTIMIZED_OUT,
+
+ /* The piece is an implicit pointer. */
+ DWARF_VALUE_IMPLICIT_POINTER
+};
+
+/* The dwarf expression stack. */
+
+struct dwarf_stack_value
+{
+ struct value *value;
+
+ /* Non-zero 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". */
+ int in_stack_memory;
+};
+
+/* The expression evaluator works with a dwarf_expr_context, describing
+ its current state and its callbacks. */
+struct dwarf_expr_context
+{
+ /* The stack of values, allocated with xmalloc. */
+ struct dwarf_stack_value *stack;
+
+ /* The number of values currently pushed on the stack, and the
+ number of elements allocated to the stack. */
+ int stack_len, stack_allocated;
+
+ /* 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 and DW_OP_GNU_addr_index arguments. */
+ CORE_ADDR offset;
+
+ /* An opaque argument provided by the caller, which will be passed
+ to all of the callback functions. */
+ void *baton;
+
+ /* Callback functions. */
+ const struct dwarf_expr_context_funcs *funcs;
/* 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. */
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.) */
+ 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.) */
int num_pieces;
struct dwarf_expr_piece *pieces;
};
-/* A piece of an object, as recorded by DW_OP_piece. */
+/* A piece of an object, as recorded by DW_OP_piece or DW_OP_bit_piece. */
struct dwarf_expr_piece
{
- /* 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;
-
- /* This piece's address or register number. */
- CORE_ADDR value;
-
- /* The length of the piece, in bytes. */
+ 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. */
+ int 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_GNU_implicit_pointer. */
+ sect_offset die;
+ /* 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;
};
struct dwarf_expr_context *new_dwarf_expr_context (void);
void free_dwarf_expr_context (struct dwarf_expr_context *ctx);
+struct cleanup *
+ make_cleanup_free_dwarf_expr_context (struct dwarf_expr_context *ctx);
-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,
+void dwarf_expr_push_address (struct dwarf_expr_context *ctx,
+ CORE_ADDR value,
+ int in_stack_memory);
+void dwarf_expr_eval (struct dwarf_expr_context *ctx, const gdb_byte *addr,
size_t len);
-CORE_ADDR dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n);
+struct value *dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n);
+CORE_ADDR dwarf_expr_fetch_address (struct dwarf_expr_context *ctx, int n);
+int dwarf_expr_fetch_in_stack_memory (struct dwarf_expr_context *ctx, int n);
+
+void dwarf_expr_require_composition (const gdb_byte *, const gdb_byte *,
+ const char *);
+
+/* Stub dwarf_expr_context_funcs implementations. */
+
+void ctx_no_get_frame_base (void *baton, const gdb_byte **start,
+ size_t *length);
+CORE_ADDR ctx_no_get_frame_cfa (void *baton);
+CORE_ADDR ctx_no_get_frame_pc (void *baton);
+CORE_ADDR ctx_no_get_tls_address (void *baton, CORE_ADDR offset);
+void ctx_no_dwarf_call (struct dwarf_expr_context *ctx, cu_offset die_offset);
+struct type *ctx_no_get_base_type (struct dwarf_expr_context *ctx,
+ cu_offset die);
+void ctx_no_push_dwarf_reg_entry_value (struct dwarf_expr_context *ctx,
+ enum call_site_parameter_kind kind,
+ union call_site_parameter_u kind_u,
+ int deref_size);
+CORE_ADDR ctx_no_get_addr_index (void *baton, unsigned int index);
+
+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)
+{
+ size_t bytes_read = read_uleb128_to_uint64 (buf, buf_end, r);
+
+ if (bytes_read == 0)
+ return NULL;
+ return buf + bytes_read;
+}
+
+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);
+
+ if (bytes_read == 0)
+ return NULL;
+ return buf + bytes_read;
+}
+
+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 addr_size);
+extern const gdb_byte *safe_skip_leb128 (const gdb_byte *buf,
+ const gdb_byte *buf_end);
#endif /* dwarf2expr.h */
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