gdb
* dwarf2read.c (save_gdb_index_command): Replace format documentation with a pointer to the manual. gdb/doc * gdb.texinfo (Index Section Format): New node. (Top): Add new node to menu.
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Tom Tromey
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@ -1,3 +1,8 @@
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2011-04-20 Tom Tromey <tromey@redhat.com>
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* dwarf2read.c (save_gdb_index_command): Replace format
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documentation with a pointer to the manual.
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2011-04-20 Pedro Alves <pedro@codesourcery.com>
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* regcache.c: Include remote.h.
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@ -1,3 +1,8 @@
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2011-04-20 Tom Tromey <tromey@redhat.com>
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* gdb.texinfo (Index Section Format): New node.
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(Top): Add new node to menu.
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2011-04-20 Pedro Alves <pedro@codesourcery.com>
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* gdb.texinfo (Maintenance Commands): Document `maint print
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@ -181,6 +181,7 @@ software in general. We will miss him.
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* Operating System Information:: Getting additional information from
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the operating system
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* Trace File Format:: GDB trace file format
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* Index Section Format:: .gdb_index section format
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* Copying:: GNU General Public License says
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how you can copy and share GDB
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* GNU Free Documentation License:: The license for this documentation
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@ -36913,6 +36914,129 @@ Trace state variable block. This records the 8-byte signed value
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Future enhancements of the trace file format may include additional types
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of blocks.
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@node Index Section Format
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@appendix @code{.gdb_index} section format
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@cindex .gdb_index section format
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@cindex index section format
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This section documents the index section that is created by @code{save
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gdb-index} (@pxref{Index Files}). The index section is
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DWARF-specific; some knowledge of DWARF is assumed in this
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description.
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The mapped index file format is designed to be directly
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@code{mmap}able on any architecture. In most cases, a datum is
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represented using a little-endian 32-bit integer value, called an
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@code{offset_type}. Big endian machines must byte-swap the values
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before using them. Exceptions to this rule are noted. The data is
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laid out such that alignment is always respected.
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A mapped index consists of several areas, laid out in order.
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@enumerate
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@item
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The file header. This is a sequence of values, of @code{offset_type}
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unless otherwise noted:
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@enumerate
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@item
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The version number, currently 4. Versions 1, 2 and 3 are obsolete.
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@item
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The offset, from the start of the file, of the CU list.
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@item
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The offset, from the start of the file, of the types CU list. Note
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that this area can be empty, in which case this offset will be equal
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to the next offset.
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@item
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The offset, from the start of the file, of the address area.
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@item
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The offset, from the start of the file, of the symbol table.
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@item
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The offset, from the start of the file, of the constant pool.
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@end enumerate
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@item
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The CU list. This is a sequence of pairs of 64-bit little-endian
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values, sorted by the CU offset. The first element in each pair is
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the offset of a CU in the @code{.debug_info} section. The second
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element in each pair is the length of that CU. References to a CU
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elsewhere in the map are done using a CU index, which is just the
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0-based index into this table. Note that if there are type CUs, then
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conceptually CUs and type CUs form a single list for the purposes of
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CU indices.
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@item
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The types CU list. This is a sequence of triplets of 64-bit
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little-endian values. In a triplet, the first value is the CU offset,
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the second value is the type offset in the CU, and the third value is
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the type signature. The types CU list is not sorted.
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@item
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The address area. The address area consists of a sequence of address
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entries. Each address entry has three elements:
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@enumerate
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@item
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The low address. This is a 64-bit little-endian value.
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@item
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The high address. This is a 64-bit little-endian value. Like
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@code{DW_AT_high_pc}, the value is one byte beyond the end.
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@item
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The CU index. This is an @code{offset_type} value.
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@end enumerate
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@item
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The symbol table. This is an open-addressed hash table. The size of
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the hash table is always a power of 2.
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Each slot in the hash table consists of a pair of @code{offset_type}
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values. The first value is the offset of the symbol's name in the
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constant pool. The second value is the offset of the CU vector in the
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constant pool.
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If both values are 0, then this slot in the hash table is empty. This
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is ok because while 0 is a valid constant pool index, it cannot be a
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valid index for both a string and a CU vector.
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The hash value for a table entry is computed by applying an
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iterative hash function to the symbol's name. Starting with an
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initial value of @code{r = 0}, each (unsigned) character @samp{c} in
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the string is incorporated into the hash using the formula
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@code{r = r * 67 + c - 113}. The terminating @samp{\0} is not
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incorporated into the hash.
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The step size used in the hash table is computed via
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@code{((hash * 17) & (size - 1)) | 1}, where @samp{hash} is the hash
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value, and @samp{size} is the size of the hash table. The step size
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is used to find the next candidate slot when handling a hash
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collision.
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The names of C@t{++} symbols in the hash table are canonicalized. We
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don't currently have a simple description of the canonicalization
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algorithm; if you intend to create new index sections, you must read
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the code.
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@item
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The constant pool. This is simply a bunch of bytes. It is organized
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so that alignment is correct: CU vectors are stored first, followed by
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strings.
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A CU vector in the constant pool is a sequence of @code{offset_type}
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values. The first value is the number of CU indices in the vector.
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Each subsequent value is the index of a CU in the CU list. This
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element in the hash table is used to indicate which CUs define the
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symbol.
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A string in the constant pool is zero-terminated.
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@end enumerate
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@include gpl.texi
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@node GNU Free Documentation License
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@ -16005,75 +16005,10 @@ write_psymtabs_to_index (struct objfile *objfile, const char *dir)
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do_cleanups (cleanup);
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}
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/* The mapped index file format is designed to be directly mmap()able
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on any architecture. In most cases, a datum is represented using a
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little-endian 32-bit integer value, called an offset_type. Big
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endian machines must byte-swap the values before using them.
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Exceptions to this rule are noted. The data is laid out such that
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alignment is always respected.
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A mapped index consists of several sections.
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1. The file header. This is a sequence of values, of offset_type
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unless otherwise noted:
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[0] The version number, currently 4. Versions 1, 2 and 3 are
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obsolete.
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[1] The offset, from the start of the file, of the CU list.
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[2] The offset, from the start of the file, of the types CU list.
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Note that this section can be empty, in which case this offset will
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be equal to the next offset.
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[3] The offset, from the start of the file, of the address section.
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[4] The offset, from the start of the file, of the symbol table.
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[5] The offset, from the start of the file, of the constant pool.
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2. The CU list. This is a sequence of pairs of 64-bit
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little-endian values, sorted by the CU offset. The first element
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in each pair is the offset of a CU in the .debug_info section. The
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second element in each pair is the length of that CU. References
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to a CU elsewhere in the map are done using a CU index, which is
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just the 0-based index into this table. Note that if there are
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type CUs, then conceptually CUs and type CUs form a single list for
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the purposes of CU indices.
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3. The types CU list. This is a sequence of triplets of 64-bit
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little-endian values. In a triplet, the first value is the CU
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offset, the second value is the type offset in the CU, and the
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third value is the type signature. The types CU list is not
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sorted.
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4. The address section. The address section consists of a sequence
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of address entries. Each address entry has three elements.
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[0] The low address. This is a 64-bit little-endian value.
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[1] The high address. This is a 64-bit little-endian value.
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Like DW_AT_high_pc, the value is one byte beyond the end.
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[2] The CU index. This is an offset_type value.
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5. The symbol table. This is a hash table. The size of the hash
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table is always a power of 2. The initial hash and the step are
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currently defined by the `find_slot' function.
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Each slot in the hash table consists of a pair of offset_type
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values. The first value is the offset of the symbol's name in the
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constant pool. The second value is the offset of the CU vector in
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the constant pool.
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If both values are 0, then this slot in the hash table is empty.
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This is ok because while 0 is a valid constant pool index, it
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cannot be a valid index for both a string and a CU vector.
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A string in the constant pool is stored as a \0-terminated string,
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as you'd expect.
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A CU vector in the constant pool is a sequence of offset_type
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values. The first value is the number of CU indices in the vector.
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Each subsequent value is the index of a CU in the CU list. This
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element in the hash table is used to indicate which CUs define the
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symbol.
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6. The constant pool. This is simply a bunch of bytes. It is
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organized so that alignment is correct: CU vectors are stored
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first, followed by strings. */
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/* Implementation of the `save gdb-index' command.
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Note that the file format used by this command is documented in the
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GDB manual. Any changes here must be documented there. */
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static void
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save_gdb_index_command (char *arg, int from_tty)
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