libbacktrace: support zstd decompression

	Support decompressing --compress-debug-sections=zstd.
	* configure.ac: Check for zstd library and
	--compress-debug-sections=zstd linker option.
	* Makefile.am (zstdtest_*): New targets.
	(zstdtest_alloc_*, ctestzstd_*): New targets.
	(BUILDTESTS): Add zstdtest, zstdtest_alloc, ctestzstd as
	appropriate.
	* elf.c (ELFCOMPRESS_ZSTD): Define.
	(elf_fetch_bits): Rename from elf_zlib_fetch.  Update uses.
	(elf_fetch_bits_backward): New static function.
	(ZLIB_HUFFMAN_*): Rename from HUFFMAN_*.  Update uses.
	(ZLIB_TABLE_*): Rename from ZDEBUG_TABLE_*.  Update uses.
	(ZSTD_TABLE_*): Define.
	(struct elf_zstd_fse_entry): Define.
	(elf_zstd_read_fse): New static function.
	(elf_zstd_build_fse): Likewise.
	(lit): Define if BACKTRACE_GENERATE_ZSTD_FSE_TABLES.
	(match, offset, next, print_table, main): Likewise.
	(elf_zstd_lit_table): New static const array.
	(elf_zstd_match_table, elf_zstd_offset_table): Likewise.
	(elf_zstd_read_huff): New static function.
	(struct elf_zstd_seq_decode): Define.
	(elf_zstd_unpack_seq_decode): New static function.
	(ZSTD_LIT_*): Define.
	(struct elf_zstd_literals): Define.
	(elf_zstd_literal_output): New static function.
	(ZSTD_LITERAL_LENGTH_BASELINE_OFFSET): Define.
	(elf_zstd_literal_length_baseline): New static const array.
	(elf_zstd_literal_length_bits): Likewise.
	(ZSTD_MATCH_LENGTH_BASELINE_OFFSET): Define.
	(elf_zstd_match_length_baseline): New static const array.
	(elf_zstd_match_length_bits): Likewise.
	(elf_zstd_decompress): New static function.
	(ZDEBUG_TABLE_SIZE): New definition.
	(elf_uncompress_chdr): Support ELF_COMPRESS_ZSTD.
	(backtrace_uncompress_zstd): New function.
	(elf_add): Use ZLIB_TABLE_SIZE for zlib-gnu sections.
	* internal.h (backtrace_uncompress_zstd): Declare.
	* zstdtest.c: New file.
	* configure, config.h.in, Makefile.in: Regenerate.

1 files changed, 30 insertions, 0 deletions

diff --git a/libbacktrace/Makefile.am b/libbacktrace/Makefile.am
index 9f8516d00e2..047b573c29a 100644
--- a/libbacktrace/Makefile.am
+++ b/libbacktrace/Makefile.am
@@ -368,6 +368,25 @@ ztest_alloc_CFLAGS = $(ztest_CFLAGS)
 
 BUILDTESTS += ztest_alloc
 
+zstdtest_SOURCES = zstdtest.c testlib.c
+zstdtest_CFLAGS = $(libbacktrace_TEST_CFLAGS) -DSRCDIR=\"$(srcdir)\"
+zstdtest_LDADD = libbacktrace.la
+zstdtest_alloc_LDADD = libbacktrace_alloc.la
+
+if HAVE_ZSTD
+zstdtest_LDADD += -lzstd
+zstdtest_alloc_LDADD += -lzstd
+endif
+zstdtest_LDADD += $(CLOCK_GETTIME_LINK)
+zstdtest_alloc_LDADD += $(CLOCK_GETTIME_LINK)
+
+BUILDTESTS += zstdtest
+
+zstdtest_alloc_SOURCES = $(zstdtest_SOURCES)
+zstdtest_alloc_CFLAGS = $(zstdtest_CFLAGS)
+
+BUILDTESTS += zstdtest_alloc
+
 endif HAVE_ELF
 
 edtest_SOURCES = edtest.c edtest2_build.c testlib.c
@@ -450,6 +469,17 @@ ctesta_LDADD = libbacktrace.la
 
 BUILDTESTS += ctestg ctesta
 
+if HAVE_COMPRESSED_DEBUG_ZSTD
+
+ctestzstd_SOURCES = btest.c testlib.c
+ctestzstd_CFLAGS = $(libbacktrace_TEST_CFLAGS)
+ctestzstd_LDFLAGS = -Wl,--compress-debug-sections=zstd
+ctestzstd_LDADD = libbacktrace.la
+
+BUILDTESTS += ctestzstd
+
+endif
+
 ctestg_alloc_SOURCES = $(ctestg_SOURCES)
 ctestg_alloc_CFLAGS = $(ctestg_CFLAGS)
 ctestg_alloc_LDFLAGS = $(ctestg_LDFLAGS)