kernel/linux.git/scripts/gendwarfksyms/die.c, branch v6.18.21

gendwarfksyms: use preferred form of sizeof for allocation

2025-07-26T06:31:30+00:00

The preferred form is to use the variable being allocated to, rather than explicitly supplying a type name which might become stale. Also do this for memset. Suggested-by: Masahiro Yamada Signed-off-by: Giuliano Procida Reviewed-by: Sami Tolvanen Signed-off-by: Masahiro Yamada

gendwarfksyms: Add a separate pass to resolve FQNs

2025-03-15T12:16:11+00:00

Using dwarf_getscopes_die to resolve fully-qualified names turns out to be rather slow, and also results in duplicate scopes being processed, which doesn't help. Simply adding an extra pass to resolve names for all DIEs before processing exports is noticeably faster. For the object files with the most exports in a defconfig+Rust build, the performance improvement is consistently >50%: rust/bindings.o: 1038 exports before: 9.5980 +- 0.0183 seconds time elapsed ( +- 0.19% ) after: 4.3116 +- 0.0287 seconds time elapsed ( +- 0.67% ) rust/core.o: 424 exports before: 5.3584 +- 0.0204 seconds time elapsed ( +- 0.38% ) after: 0.05348 +- 0.00129 seconds time elapsed ( +- 2.42% ) ^ Not a mistake. net/core/dev.o: 190 exports before: 9.0507 +- 0.0297 seconds time elapsed ( +- 0.33% ) after: 3.2882 +- 0.0165 seconds time elapsed ( +- 0.50% ) rust/kernel.o: 129 exports before: 6.8571 +- 0.0317 seconds time elapsed ( +- 0.46% ) after: 2.9096 +- 0.0316 seconds time elapsed ( +- 1.09% ) net/core/skbuff.o: 120 exports before: 5.4805 +- 0.0291 seconds time elapsed ( +- 0.53% ) after: 2.0339 +- 0.0231 seconds time elapsed ( +- 1.14% ) drivers/gpu/drm/display/drm_dp_helper.o: 101 exports before: 1.7877 +- 0.0187 seconds time elapsed ( +- 1.05% ) after: 0.69245 +- 0.00994 seconds time elapsed ( +- 1.44% ) net/core/sock.o: 97 exports before: 5.8327 +- 0.0653 seconds time elapsed ( +- 1.12% ) after: 2.0784 +- 0.0291 seconds time elapsed ( +- 1.40% ) drivers/net/phy/phy_device.o: 95 exports before: 3.0671 +- 0.0371 seconds time elapsed ( +- 1.21% ) after: 1.2127 +- 0.0207 seconds time elapsed ( +- 1.70% ) drivers/pci/pci.o: 93 exports before: 1.1130 +- 0.0113 seconds time elapsed ( +- 1.01% ) after: 0.4848 +- 0.0127 seconds time elapsed ( +- 2.63% ) kernel/sched/core.o: 83 exports before: 3.5092 +- 0.0223 seconds time elapsed ( +- 0.64% ) after: 1.1231 +- 0.0145 seconds time elapsed ( +- 1.29% ) Overall, a defconfig+DWARF5 build with gendwarfksyms and Rust is 14.8% faster with this patch applied on my test system. Without Rust, there's still a 10.4% improvement in build time when gendwarfksyms is used. Note that symbol versions are unchanged with this patch. Suggested-by: Giuliano Procida Signed-off-by: Sami Tolvanen Signed-off-by: Masahiro Yamada

gendwarfksyms: Add symtypes output

2025-01-10T16:25:25+00:00

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' 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 Reviewed-by: Petr Pavlu Signed-off-by: Masahiro Yamada

gendwarfksyms: Expand type modifiers and typedefs

2025-01-10T16:25:25+00:00

Add support for expanding DWARF type modifiers, such as pointers, const values etc., and typedefs. These types all have DW_AT_type attribute pointing to the underlying type, and thus produce similar output. Also add linebreaks and indentation to debugging output to make it more readable. Signed-off-by: Sami Tolvanen Reviewed-by: Petr Pavlu Signed-off-by: Masahiro Yamada

gendwarfksyms: Add a cache for processed DIEs

2025-01-10T16:25:25+00:00

Basic types in DWARF repeat frequently and traversing the DIEs using libdw is relatively slow. Add a simple hashtable based cache for the processed DIEs. Signed-off-by: Sami Tolvanen Reviewed-by: Petr Pavlu Signed-off-by: Masahiro Yamada