Squashed 'third_party/elfutils/' content from commit 555e15e
Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/libebl/libebl.h b/libebl/libebl.h
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+/* Interface for libebl.
+ Copyright (C) 2000-2010, 2013, 2014, 2015, 2016, 2017 Red Hat, Inc.
+ This file is part of elfutils.
+
+ This file is free software; you can redistribute it and/or modify
+ it under the terms of either
+
+ * the GNU Lesser General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at
+ your option) any later version
+
+ or
+
+ * the GNU General Public License as published by the Free
+ Software Foundation; either version 2 of the License, or (at
+ your option) any later version
+
+ or both in parallel, as here.
+
+ elfutils is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received copies of the GNU General Public License and
+ the GNU Lesser General Public License along with this program. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+
+/* This is the interface for the Elfutils Backend Library.
+ It is a completely UNSUPPORTED interface. Don't use any libebl
+ function directly. These are only for internal elfutils backends
+ and tools. There is NO source or binary compatible guarantee.
+
+ The ABI of the backend modules is not guaranteed. Really, no guarantee
+ whatsoever. We are enforcing this in the code. The modules and their
+ users must match. No third-party EBL module are supported or allowed.
+ The only reason there are separate modules is to not have the code for
+ all architectures in all the binaries. */
+
+
+#ifndef _LIBEBL_H
+#define _LIBEBL_H 1
+
+#include <gelf.h>
+#include "libdw.h"
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "elf-knowledge.h"
+
+
+/* Opaque type for the handle. */
+typedef struct ebl Ebl;
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Get backend handle for object associated with ELF handle. */
+extern Ebl *ebl_openbackend (Elf *elf);
+/* Similar but without underlying ELF file. */
+extern Ebl *ebl_openbackend_machine (GElf_Half machine);
+/* Similar but with emulation name given. */
+extern Ebl *ebl_openbackend_emulation (const char *emulation);
+
+/* Free resources allocated for backend handle. */
+extern void ebl_closebackend (Ebl *bh);
+
+
+/* Information about the descriptor. */
+
+/* Get ELF machine. */
+extern int ebl_get_elfmachine (Ebl *ebl) __pure_attribute__;
+
+/* Get ELF class. */
+extern int ebl_get_elfclass (Ebl *ebl) __pure_attribute__;
+
+/* Get ELF data encoding. */
+extern int ebl_get_elfdata (Ebl *ebl) __pure_attribute__;
+
+
+/* Function to call the callback functions including default ELF
+ handling. */
+
+/* Return backend name. */
+extern const char *ebl_backend_name (Ebl *ebl);
+
+/* Return relocation type name. */
+extern const char *ebl_reloc_type_name (Ebl *ebl, int reloc,
+ char *buf, size_t len);
+
+/* Check relocation type. */
+extern bool ebl_reloc_type_check (Ebl *ebl, int reloc);
+
+/* Check relocation type use. */
+extern bool ebl_reloc_valid_use (Ebl *ebl, int reloc);
+
+/* Check if relocation type is for simple absolute relocations.
+ Return ELF_T_{BYTE,HALF,SWORD,SXWORD} for a simple type, else ELF_T_NUM. */
+extern Elf_Type ebl_reloc_simple_type (Ebl *ebl, int reloc);
+
+/* Return true if the symbol type is that referencing the GOT. E.g.,
+ R_386_GOTPC. */
+extern bool ebl_gotpc_reloc_check (Ebl *ebl, int reloc);
+
+/* Return segment type name. */
+extern const char *ebl_segment_type_name (Ebl *ebl, int segment,
+ char *buf, size_t len);
+
+/* Return section type name. */
+extern const char *ebl_section_type_name (Ebl *ebl, int section,
+ char *buf, size_t len);
+
+/* Return section name. */
+extern const char *ebl_section_name (Ebl *ebl, int section, int xsection,
+ char *buf, size_t len,
+ const char *scnnames[], size_t shnum);
+
+/* Return machine flag names. */
+extern const char *ebl_machine_flag_name (Ebl *ebl, GElf_Word flags,
+ char *buf, size_t len);
+
+/* Check whether machine flag is valid. */
+extern bool ebl_machine_flag_check (Ebl *ebl, GElf_Word flags);
+
+/* Check whether SHF_MASKPROC flags are valid. */
+extern bool ebl_machine_section_flag_check (Ebl *ebl, GElf_Xword flags);
+
+/* Check whether the section with the given index, header, and name
+ is a special machine section that is valid despite a combination
+ of flags or other details that are not generically valid. */
+extern bool ebl_check_special_section (Ebl *ebl, int ndx,
+ const GElf_Shdr *shdr, const char *name);
+
+/* Return symbol type name. */
+extern const char *ebl_symbol_type_name (Ebl *ebl, int symbol,
+ char *buf, size_t len);
+
+/* Return symbol binding name. */
+extern const char *ebl_symbol_binding_name (Ebl *ebl, int binding,
+ char *buf, size_t len);
+
+/* Return dynamic tag name. */
+extern const char *ebl_dynamic_tag_name (Ebl *ebl, int64_t tag,
+ char *buf, size_t len);
+
+/* Check dynamic tag. */
+extern bool ebl_dynamic_tag_check (Ebl *ebl, int64_t tag);
+
+/* Check whether given symbol's st_value and st_size are OK despite failing
+ normal checks. */
+extern bool ebl_check_special_symbol (Ebl *ebl, GElf_Ehdr *ehdr,
+ const GElf_Sym *sym, const char *name,
+ const GElf_Shdr *destshdr);
+
+/* Check if this is a data marker symbol. e.g. '$d' symbols for ARM. */
+extern bool ebl_data_marker_symbol (Ebl *ebl, const GElf_Sym *sym,
+ const char *sname);
+
+/* Check whether only valid bits are set on the st_other symbol flag. */
+extern bool ebl_check_st_other_bits (Ebl *ebl, unsigned char st_other);
+
+/* Return symbolic representation of OS ABI. */
+extern const char *ebl_osabi_name (Ebl *ebl, int osabi, char *buf, size_t len);
+
+
+/* Return name of the note section type for a core file. */
+extern const char *ebl_core_note_type_name (Ebl *ebl, uint32_t type, char *buf,
+ size_t len);
+
+/* Return name of the note section type for an object file. */
+extern const char *ebl_object_note_type_name (Ebl *ebl, const char *name,
+ uint32_t type, char *buf,
+ size_t len);
+
+/* Print information about object note if available. */
+extern void ebl_object_note (Ebl *ebl, const char *name, uint32_t type,
+ uint32_t descsz, const char *desc);
+
+/* Check whether an attribute in a .gnu_attributes section is recognized.
+ Fills in *TAG_NAME with the name for this tag.
+ If VALUE is a known value for that tag, also fills in *VALUE_NAME. */
+extern bool ebl_check_object_attribute (Ebl *ebl, const char *vendor,
+ int tag, uint64_t value,
+ const char **tag_name,
+ const char **value_name);
+
+/* Check whether a section type is a valid reloc target. */
+extern bool ebl_check_reloc_target_type (Ebl *ebl, Elf64_Word sh_type);
+
+
+/* Check section name for being that of a debug informatino section. */
+extern bool ebl_debugscn_p (Ebl *ebl, const char *name);
+
+/* Check whether given relocation is a copy relocation. */
+extern bool ebl_copy_reloc_p (Ebl *ebl, int reloc);
+
+/* Check whether given relocation is a no-op relocation. */
+extern bool ebl_none_reloc_p (Ebl *ebl, int reloc);
+
+/* Check whether given relocation is a relative relocation. */
+extern bool ebl_relative_reloc_p (Ebl *ebl, int reloc);
+
+/* Check whether section should be stripped. */
+extern bool ebl_section_strip_p (Ebl *ebl, const GElf_Ehdr *ehdr,
+ const GElf_Shdr *shdr, const char *name,
+ bool remove_comment, bool only_remove_debug);
+
+/* Check if backend uses a bss PLT in this file. */
+extern bool ebl_bss_plt_p (Ebl *ebl);
+
+/* Return size of entry in SysV-style hash table. */
+extern int ebl_sysvhash_entrysize (Ebl *ebl);
+
+/* Return location expression to find return value given a
+ DW_TAG_subprogram, DW_TAG_subroutine_type, or similar DIE describing
+ function itself (whose DW_AT_type attribute describes its return type).
+ Returns -1 for a libdw error (see dwarf_errno).
+ Returns -2 for an unrecognized type formation.
+ Returns zero if the function has no return value (e.g. "void" in C).
+ Otherwise, *LOCOPS gets a location expression to find the return value,
+ and returns the number of operations in the expression. The pointer is
+ permanently allocated at least as long as the Ebl handle is open. */
+extern int ebl_return_value_location (Ebl *ebl,
+ Dwarf_Die *functypedie,
+ const Dwarf_Op **locops);
+
+/* Fill in register information given DWARF register numbers.
+ If NAME is null, return the maximum REGNO + 1 that has a name.
+ Otherwise, store in NAME the name for DWARF register number REGNO
+ and return the number of bytes written (including '\0' terminator).
+ Return -1 if NAMELEN is too short or REGNO is negative or too large.
+ Return 0 if REGNO is unused (a gap in the DWARF number assignment).
+ On success, set *SETNAME to a description like "integer" or "FPU"
+ fit for "%s registers" title display, and *PREFIX to the string
+ that precedes NAME in canonical assembler syntax (e.g. "%" or "$").
+ The NAME string contains identifier characters only (maybe just digits). */
+extern ssize_t ebl_register_info (Ebl *ebl,
+ int regno, char *name, size_t namelen,
+ const char **prefix, const char **setname,
+ int *bits, int *type);
+
+/* Fill in the DWARF register numbers for the registers used in system calls.
+ The SP and PC are what kernel reports call the user stack pointer and PC.
+ The CALLNO and ARGS are the system call number and incoming arguments.
+ Each of these is filled with the DWARF register number corresponding,
+ or -1 if there is none. Returns zero when the information is available. */
+extern int ebl_syscall_abi (Ebl *ebl, int *sp, int *pc,
+ int *callno, int args[6]);
+
+/* Supply the ABI-specified state of DWARF CFI before CIE initial programs.
+
+ The DWARF 3.0 spec says that the default initial states of all registers
+ are "undefined", unless otherwise specified by the machine/compiler ABI.
+
+ This default is wrong for every machine with the CFI generated by GCC.
+ The EH unwinder does not really distinguish "same_value" and "undefined",
+ since it doesn't matter for unwinding (in either case there is no change
+ to make for that register). GCC generates CFI that says nothing at all
+ about registers it hasn't spilled somewhere. For our unwinder to give
+ the true story, the backend must supply an initial state that uses
+ "same_value" rules for all the callee-saves registers.
+
+ This can fill in the initial_instructions, initial_instructions_end
+ members of *ABI_INFO to point at a CFI instruction stream to process
+ before each CIE's initial instructions. It should set the
+ data_alignment_factor member if it affects the initial instructions.
+
+ The callback should not use the register rules DW_CFA_expression or
+ DW_CFA_val_expression. Defining the CFA using DW_CFA_def_cfa_expression
+ is allowed. This is an implementation detail since register rules
+ store expressions as offsets from the .eh_frame or .debug_frame data.
+
+ As a shorthand for some common cases, for this instruction stream
+ we overload some CFI instructions that cannot be used in a CIE:
+
+ DW_CFA_restore -- Change default rule for all unmentioned
+ registers from undefined to same_value.
+
+ This function can also fill in ABI_INFO->return_address_register with the
+ DWARF register number that identifies the actual PC in machine state.
+ If there is no canonical DWARF register number with that meaning, it's
+ left unchanged (callers usually initialize with (Dwarf_Word) -1).
+ This value is not used by CFI per se.
+
+ Function returns 0 on success and -1 for error or unsupported by the
+ backend. */
+extern int ebl_abi_cfi (Ebl *ebl, Dwarf_CIE *abi_info)
+ __nonnull_attribute__ (2);
+
+/* Register map info. */
+typedef struct
+{
+ Dwarf_Half offset; /* Byte offset in register data block. */
+ Dwarf_Half regno; /* DWARF register number. */
+ uint8_t bits; /* Bits of data for one register. */
+ uint8_t pad; /* Bytes of padding after register's data. */
+ Dwarf_Half count; /* Consecutive register numbers here. */
+ bool pc_register;
+} Ebl_Register_Location;
+
+/* Non-register data items in core notes. */
+typedef struct
+{
+ const char *name; /* Printable identifier. */
+ const char *group; /* Identifier for category of related items. */
+ Dwarf_Half offset; /* Byte offset in note data. */
+ Dwarf_Half count;
+ Elf_Type type;
+ char format;
+ bool thread_identifier;
+ bool pc_register;
+} Ebl_Core_Item;
+
+/* Describe the format of a core file note with the given header and NAME.
+ NAME is not guaranteed terminated, it's NHDR->n_namesz raw bytes. */
+extern int ebl_core_note (Ebl *ebl, const GElf_Nhdr *nhdr, const char *name,
+ GElf_Word *regs_offset, size_t *nregloc,
+ const Ebl_Register_Location **reglocs,
+ size_t *nitems, const Ebl_Core_Item **items)
+ __nonnull_attribute__ (1, 2, 3, 4, 5, 6, 7, 8);
+
+/* Describe the auxv type number. */
+extern int ebl_auxv_info (Ebl *ebl, GElf_Xword a_type,
+ const char **name, const char **format)
+ __nonnull_attribute__ (1, 3, 4);
+
+/* Callback type for ebl_set_initial_registers_tid.
+ Register -1 is mapped to PC (if arch PC has no DWARF number).
+ If FIRSTREG is -1 then NREGS has to be 1. */
+typedef bool (ebl_tid_registers_t) (int firstreg, unsigned nregs,
+ const Dwarf_Word *regs, void *arg)
+ __nonnull_attribute__ (3);
+
+/* Callback to fetch process data from live TID.
+ EBL architecture has to have EBL_FRAME_NREGS > 0, otherwise the
+ backend doesn't support unwinding and this function call may crash. */
+extern bool ebl_set_initial_registers_tid (Ebl *ebl,
+ pid_t tid,
+ ebl_tid_registers_t *setfunc,
+ void *arg)
+ __nonnull_attribute__ (1, 3);
+
+/* Number of registers to allocate for ebl_set_initial_registers_tid.
+ EBL architecture can unwind iff EBL_FRAME_NREGS > 0. */
+extern size_t ebl_frame_nregs (Ebl *ebl)
+ __nonnull_attribute__ (1);
+
+/* Offset to apply to the value of the return_address_register, as
+ fetched from a Dwarf CFI. This is used by some backends, where the
+ return_address_register actually contains the call address. */
+extern int ebl_ra_offset (Ebl *ebl)
+ __nonnull_attribute__ (1);
+
+/* Mask to use for function symbol or unwind return addresses in case
+ the architecture adds some extra non-address bits to it. This is
+ different from ebl_resolve_sym_value which only works for actual
+ symbol addresses (in non-ET_REL files) that might resolve to an
+ address in a different section. ebl_func_addr_mask is called to
+ turn a given function value into the a real address or offset (the
+ original value might not be a real address). This works for all
+ cases where an actual function address (or offset in ET_REL symbol
+ tables) is needed. */
+extern GElf_Addr ebl_func_addr_mask (Ebl *ebl);
+
+/* Convert *REGNO as is in DWARF to a lower range suitable for
+ Dwarf_Frame->REGS indexing. */
+extern bool ebl_dwarf_to_regno (Ebl *ebl, unsigned *regno)
+ __nonnull_attribute__ (1, 2);
+
+/* Modify PC as fetched from inferior data into valid PC. */
+extern void ebl_normalize_pc (Ebl *ebl, Dwarf_Addr *pc)
+ __nonnull_attribute__ (1, 2);
+
+/* Callback type for ebl_unwind's parameter getfunc. */
+typedef bool (ebl_tid_registers_get_t) (int firstreg, unsigned nregs,
+ Dwarf_Word *regs, void *arg)
+ __nonnull_attribute__ (3);
+
+/* Callback type for ebl_unwind's parameter readfunc. */
+typedef bool (ebl_pid_memory_read_t) (Dwarf_Addr addr, Dwarf_Word *data,
+ void *arg)
+ __nonnull_attribute__ (3);
+
+/* Get previous frame state for an existing frame state. Method is called only
+ if unwinder could not find CFI for current PC. PC is for the
+ existing frame. SETFUNC sets register in the previous frame. GETFUNC gets
+ register from the existing frame. Note that GETFUNC vs. SETFUNC act on
+ a disjunct set of registers. READFUNC reads memory. ARG has to be passed
+ for SETFUNC, GETFUNC and READFUNC. *SIGNAL_FRAMEP is initialized to false,
+ it can be set to true if existing frame is a signal frame. SIGNAL_FRAMEP is
+ never NULL. */
+extern bool ebl_unwind (Ebl *ebl, Dwarf_Addr pc, ebl_tid_registers_t *setfunc,
+ ebl_tid_registers_get_t *getfunc,
+ ebl_pid_memory_read_t *readfunc, void *arg,
+ bool *signal_framep)
+ __nonnull_attribute__ (1, 3, 4, 5, 7);
+
+/* Returns true if the value can be resolved to an address in an
+ allocated section, which will be returned in *ADDR
+ (e.g. function descriptor resolving) */
+extern bool ebl_resolve_sym_value (Ebl *ebl, GElf_Addr *addr)
+ __nonnull_attribute__ (2);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* libebl.h */