NAME

dwarf_get_fde_info_for_all_regs3 —

retrieve register rule row

LIBRARY

DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS

#include <libdwarf.h>

int
dwarf_get_fde_info_for_all_regs3(Dwarf_Fde fde, Dwarf_Addr pc, Dwarf_Regtable3 *reg_table, Dwarf_Addr *row_pc, Dwarf_Error *err);

DESCRIPTION

Function dwarf_get_fde_info_for_all_regs3() retrieves a row from the register rule table associated with the given FDE descriptor.

Argument fde should reference a valid DWARF FDE descriptor.

Argument pc should hold the program counter address to be used to locate the desired table row.

Argument reg_table should point to a Dwarf_Regtable3 descriptor which will hold the returned table row of register rules. The Dwarf_Regtable3 descriptor is defined in the header file <libdwarf.h>:

typedef struct {
	Dwarf_Small	dw_offset_relevant;
	Dwarf_Small	dw_value_type;
	Dwarf_Half	dw_regnum;
	Dwarf_Unsigned	dw_offset_or_block_len;
	Dwarf_Ptr	dw_block_ptr;
} Dwarf_Regtable_Entry3;

typedef struct {
	Dwarf_Regtable_Entry3	rt3_cfa_rule;
	Dwarf_Half		rt3_reg_table_size;
	Dwarf_Regtable_Entry3	*rt3_rules;
} Dwarf_Regtable3;

The rt3_reg_table_size field specifies the maximum number of register rule columns to be returned, and should be set by the application before calling the function. The rt3_rules field should point to a memory arena allocated by the application with space for at least rt3_reg_table_size descriptors of type Dwarf_Regtable_Entry3.

On a successful execution of this function, the rt3_cfa_rule field will be set to the CFA register rule associated with the table row, and the rt3_rules array will hold the returned register rules contained in the table row.

For each register rule descriptor returned, the dw_offset_relevant field will be set to 1 if the register rule has a offset value, the dw_value_type field will be set to the type code of the register rule and the dw_regnum field will be set to the register number associated with the register rule. If the register rule is of type DW_EXPR_OFFSET or DW_EXPR_VAL_OFFSET, the dw_offset_or_block_len field will be set to the offset value associated with the register rule. If the type is DW_EXPR_EXPRESSION or DW_EXPR_VAL_EXPRESSION, the dw_offset_or_block_len field will be set to the length in bytes of the DWARF expression block associated with the register rule. The dw_block_ptr field will be set to a pointer to the content of the DWARF expression block associated with the register rule.

Argument row_pc should point to a location which will be set to the lowest program counter address associated with the table row.

If argument err is not NULL, it will be used to store error information in case of an error.

RETURN VALUES

Function dwarf_get_fde_info_for_all_regs3() returns DW_DLV_OK when it succeeds. In case of an error, it returns DW_DLV_ERROR and sets the argument err.

ERRORS

Function dwarf_get_fde_info_for_all_regs3() can fail with:

[DW_DLE_ARGUMENT]: One of the arguments fde, reg_table or row_pc was NULL.
[DW_DLE_PC_NOT_IN_FDE_RANGE]: The program counter value provided in argument pc did not fall in the range covered by argument fde.