dwarf_add_expr_gen —
add an operator to a location expression
descriptor
DWARF Access Library (libdwarf, -ldwarf)
#include
<libdwarf.h>
Dwarf_Unsigned
dwarf_add_expr_gen(
Dwarf_P_Expr
expr,
Dwarf_Small opcode,
Dwarf_Unsigned val1,
Dwarf_Unsigned val2,
Dwarf_Error *err);
Function
dwarf_add_expr_gen() adds a location
expression operator to the location expression descriptor referenced by
argument
expr.
Argument
expr should reference a location
expression descriptor allocated using the function
dwarf_new_expr(3).
Argument
opcode specifies the operation code of
the location expression operator. Valid values for this argument are those
denoted by the
DW_OP_
* constants defined in
<libdwarf.h>.
To generate a
DW_OP_addr
operation,
application code should instead use
dwarf_add_expr_addr_b(3).
Argument
val1 specifies the first operand of
the location expression operator.
Argument
val2 specifies the second operand of
the location expression operator.
If argument
err is not NULL, it will be used to
store error information in case of an error.
On success, function
dwarf_add_expr_gen() returns
the size in bytes of the location expression byte stream generated. In case of
an error, function
dwarf_add_expr_gen() returns
DW_DLV_NOCOUNT
and sets the argument
err.
Function
dwarf_add_expr_gen() can fail with:
-
-
- [
DW_DLE_ARGUMENT
]
- Argument expr was
NULL.
-
-
- [
DW_DLE_LOC_EXPR_BAD
]
- The operation code specified in argument
opcode was invalid.
-
-
- [
DW_DLE_MEMORY
]
- An out of memory condition was encountered during the
execution of the function.
dwarf(3),
dwarf_add_AT_location_expr(3),
dwarf_add_expr_addr(3),
dwarf_add_expr_addr_b(3),
dwarf_expr_current_offset(3),
dwarf_expr_into_block(3),
dwarf_new_expr(3)