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path: root/scripts/gendwarfksyms/symbols.c
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2025-01-11gendwarfksyms: Add support for symbol type pointersSami Tolvanen
The compiler may choose not to emit type information in DWARF for external symbols. Clang, for example, does this for symbols not defined in the current TU. To provide a way to work around this issue, add support for __gendwarfksyms_ptr_<symbol> pointers that force the compiler to emit the necessary type information in DWARF also for the missing symbols. Example usage: #define GENDWARFKSYMS_PTR(sym) \ static typeof(sym) *__gendwarfksyms_ptr_##sym __used \ __section(".discard.gendwarfksyms") = &sym; extern int external_symbol(void); GENDWARFKSYMS_PTR(external_symbol); Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-01-11gendwarfksyms: Add symbol versioningSami Tolvanen
Calculate symbol versions from the fully expanded type strings in type_map, and output the versions in a genksyms-compatible format. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-01-11gendwarfksyms: Add symtypes outputSami Tolvanen
Add support for producing genksyms-style symtypes files. Process die_map to find the longest expansions for each type, and use symtypes references in type definitions. The basic file format is similar to genksyms, with two notable exceptions: 1. Type names with spaces (common with Rust) in references are wrapped in single quotes. E.g.: s#'core::result::Result<u8, core::num::error::ParseIntError>' 2. The actual type definition is the simple parsed DWARF format we output with --dump-dies, not the preprocessed C-style format genksyms produces. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-01-11gendwarfksyms: Add address matchingSami Tolvanen
The compiler may choose not to emit type information in DWARF for all aliases, but it's possible for each alias to be exported separately. To ensure we find type information for the aliases as well, read {section, address} tuples from the symbol table and match symbols also by address. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-01-11tools: Add gendwarfksymsSami Tolvanen
Add a basic DWARF parser, which uses libdw to traverse the debugging information in an object file and looks for functions and variables. In follow-up patches, this will be expanded to produce symbol versions for CONFIG_MODVERSIONS from DWARF. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>