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/* libunwind - a platform-independent unwind library
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Copyright (c) 2003 Hewlett-Packard Development Company, L.P.
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Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
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This file is part of libunwind.
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/* This header file defines the format of a DWARF exception-header
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section (.eh_frame_hdr, pointed to by program-header
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PT_GNU_EH_FRAME). The exception-header is self-describing in the
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sense that the format of the addresses contained in it is expressed
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as a one-byte type-descriptor called a "pointer-encoding" (PE).
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The exception header encodes the address of the .eh_frame section
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and optionally contains a binary search table for the
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Frame Descriptor Entries (FDEs) in the .eh_frame. The contents of
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.eh_frame has the format described by the DWARF v3 standard
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(http://www.eagercon.com/dwarf/dwarf3std.htm), except that code
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addresses may be encoded in different ways. Also, .eh_frame has
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augmentations that allow encoding a language-specific data-area
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(LSDA) pointer and a pointer to a personality-routine.
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The Common Information Entry (CIE) associated with an FDE may
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contain an augmentation string. Each character in this string has
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a specific meaning and either one or two associated operands. The
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operands are stored in an augmentation body which appears right
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after the "return_address_register" member and before the
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"initial_instructions" member. The operands appear in the order
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in which the characters appear in the string. For example, if the
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augmentation string is "zL", the operand for 'z' would be first in
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the augmentation body and the operand for 'L' would be second.
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The following characters are supported for the CIE augmentation
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'z': The operand for this character is a uleb128 value that gives the
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length of the CIE augmentation body, not counting the length
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of the uleb128 operand itself. If present, this code must
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appear as the first character in the augmentation body.
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'L': Indicates that the FDE's augmentation body contains an LSDA
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pointer. The operand for this character is a single byte
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that specifies the pointer-encoding (PE) that is used for
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'R': Indicates that the code-pointers (FDE members
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"initial_location" and "address_range" and the operand for
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DW_CFA_set_loc) in the FDE have a non-default encoding. The
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operand for this character is a single byte that specifies
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the pointer-encoding (PE) that is used for the
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code-pointers. Note: the "address_range" member is always
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encoded as an absolute value. Apart from that, the specified
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FDE pointer-encoding applies.
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'P': Indicates the presence of a personality routine (handler).
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The first operand for this character specifies the
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pointer-encoding (PE) that is used for the second operand,
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which specifies the address of the personality routine.
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If the augmentation string contains any other characters, the
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remainder of the augmentation string should be ignored.
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Furthermore, if the size of the augmentation body is unknown
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(i.e., 'z' is not the first character of the augmentation string),
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then the entire CIE as well all associated FDEs must be ignored.
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A Frame Descriptor Entries (FDE) may contain an augmentation body
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which, if present, appears right after the "address_range" member
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and before the "instructions" member. The contents of this body
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is implicitly defined by the augmentation string of the associated
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CIE. The meaning of the characters in the CIE's augmentation
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string as far as FDEs are concerned is as follows:
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'z': The first operand in the FDE's augmentation body specifies
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the total length of the augmentation body as a uleb128 (not
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counting the length of the uleb128 operand itself).
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'L': The operand for this character is an LSDA pointer, encoded
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in the format specified by the corresponding operand in the
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CIE's augmentation body.
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#define DW_EH_VERSION 1 /* The version we're implementing */
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struct dwarf_eh_frame_hdr
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unsigned char version;
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unsigned char eh_frame_ptr_enc;
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unsigned char fde_count_enc;
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unsigned char table_enc;
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/* The rest of the header is variable-length and consists of the
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encoded_t eh_frame_ptr;
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encoded_t start_ip; // first address covered by this FDE
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encoded_t fde_addr; // address of the FDE
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binary_search_table[fde_count]; */
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#endif /* dwarf_eh_h */
added
removed
src/dwarf/dwarf-eh.h
