5 files changed, 114 insertions, 0 deletions
diff --git a/src/liblzma/common/block_buffer_encoder.c b/src/liblzma/common/block_buffer_encoder.c
index 39e263aa..a47342ef 100644
--- a/src/liblzma/common/block_buffer_encoder.c
+++ b/src/liblzma/common/block_buffer_encoder.c
@@ -325,6 +325,24 @@ lzma_block_buffer_encode(lzma_block *block, const lzma_allocator *allocator,
 }
 
 
+#ifdef HAVE_SYMBOL_VERSIONS_LINUX
+// This is for compatibility with binaries linked against liblzma that
+// has been patched with xz-5.2.2-compat-libs.patch from RHEL/CentOS 7.
+LZMA_SYMVER_API("lzma_block_uncomp_encode@XZ_5.2.2",
+	lzma_ret, lzma_block_uncomp_encode_522)(lzma_block *block,
+		const uint8_t *in, size_t in_size,
+		uint8_t *out, size_t *out_pos, size_t out_size)
+		lzma_nothrow lzma_attr_warn_unused_result
+		__attribute__((__alias__("lzma_block_uncomp_encode_52")));
+
+LZMA_SYMVER_API("lzma_block_uncomp_encode@@XZ_5.2",
+	lzma_ret, lzma_block_uncomp_encode_52)(lzma_block *block,
+		const uint8_t *in, size_t in_size,
+		uint8_t *out, size_t *out_pos, size_t out_size)
+		lzma_nothrow lzma_attr_warn_unused_result;
+
+#define lzma_block_uncomp_encode lzma_block_uncomp_encode_52
+#endif
 extern LZMA_API(lzma_ret)
 lzma_block_uncomp_encode(lzma_block *block,
 		const uint8_t *in, size_t in_size,
diff --git a/src/liblzma/common/common.c b/src/liblzma/common/common.c
index cf714e5e..10fc8840 100644
--- a/src/liblzma/common/common.c
+++ b/src/liblzma/common/common.c
@@ -366,6 +366,20 @@ lzma_end(lzma_stream *strm)
 }
 
 
+#ifdef HAVE_SYMBOL_VERSIONS_LINUX
+// This is for compatibility with binaries linked against liblzma that
+// has been patched with xz-5.2.2-compat-libs.patch from RHEL/CentOS 7.
+LZMA_SYMVER_API("lzma_get_progress@XZ_5.2.2",
+	void, lzma_get_progress_522)(lzma_stream *strm,
+		uint64_t *progress_in, uint64_t *progress_out) lzma_nothrow
+		__attribute__((__alias__("lzma_get_progress_52")));
+
+LZMA_SYMVER_API("lzma_get_progress@@XZ_5.2",
+	void, lzma_get_progress_52)(lzma_stream *strm,
+		uint64_t *progress_in, uint64_t *progress_out) lzma_nothrow;
+
+#define lzma_get_progress lzma_get_progress_52
+#endif
 extern LZMA_API(void)
 lzma_get_progress(lzma_stream *strm,
 		uint64_t *progress_in, uint64_t *progress_out)
diff --git a/src/liblzma/common/common.h b/src/liblzma/common/common.h
index b3d3b7a0..6b659c66 100644
--- a/src/liblzma/common/common.h
+++ b/src/liblzma/common/common.h
@@ -34,6 +34,34 @@
 
 #include "lzma.h"
 
+#ifdef HAVE_SYMBOL_VERSIONS_LINUX
+// To keep link-time optimization (LTO, -flto) working with GCC,
+// the __symver__ attribute must be used instead of __asm__(".symver ...").
+// Otherwise the symbol versions may be lost, resulting in broken liblzma
+// that has wrong default versions in the exported symbol list!
+// The attribute was added in GCC 10; LTO with older GCC is not supported.
+//
+// To keep -Wmissing-prototypes happy, use LZMA_SYMVER_API only with function
+// declarations (including those with __alias__ attribute) and LZMA_API with
+// the function definitions. This means a little bit of silly copy-and-paste
+// between declarations and definitions though.
+//
+// As of GCC 12.2, the __symver__ attribute supports only @ and @@ but the
+// very convenient @@@ isn't supported (it's supported by GNU assembler
+// since 2000). When using @@ instead of @@@, the internal name must not be
+// the same as the external name to avoid problems in some situations. This
+// is why "#define foo_52 foo" is needed for the default symbol versions.
+#	if TUKLIB_GNUC_REQ(10, 0)
+#		define LZMA_SYMVER_API(extnamever, type, intname) \
+			extern __attribute__((__symver__(extnamever))) \
+					LZMA_API(type) intname
+#	else
+#		define LZMA_SYMVER_API(extnamever, type, intname) \
+			__asm__(".symver " #intname "," extnamever); \
+			extern LZMA_API(type) intname
+#	endif
+#endif
+
 // These allow helping the compiler in some often-executed branches, whose
 // result is almost always the same.
 #ifdef __GNUC__
diff --git a/src/liblzma/common/hardware_cputhreads.c b/src/liblzma/common/hardware_cputhreads.c
index f468366a..5d246d2c 100644
--- a/src/liblzma/common/hardware_cputhreads.c
+++ b/src/liblzma/common/hardware_cputhreads.c
@@ -15,6 +15,18 @@
 #include "tuklib_cpucores.h"
 
 
+#ifdef HAVE_SYMBOL_VERSIONS_LINUX
+// This is for compatibility with binaries linked against liblzma that
+// has been patched with xz-5.2.2-compat-libs.patch from RHEL/CentOS 7.
+LZMA_SYMVER_API("lzma_cputhreads@XZ_5.2.2",
+	uint32_t, lzma_cputhreads_522)(void) lzma_nothrow
+		__attribute__((__alias__("lzma_cputhreads_52")));
+
+LZMA_SYMVER_API("lzma_cputhreads@@XZ_5.2",
+	uint32_t, lzma_cputhreads_52)(void) lzma_nothrow;
+
+#define lzma_cputhreads lzma_cputhreads_52
+#endif
 extern LZMA_API(uint32_t)
 lzma_cputhreads(void)
 {
diff --git a/src/liblzma/common/stream_encoder_mt.c b/src/liblzma/common/stream_encoder_mt.c
index 2ab4d048..819b2273 100644
--- a/src/liblzma/common/stream_encoder_mt.c
+++ b/src/liblzma/common/stream_encoder_mt.c
@@ -1078,6 +1078,31 @@ stream_encoder_mt_init(lzma_next_coder *next, const lzma_allocator *allocator,
 }
 
 
+#ifdef HAVE_SYMBOL_VERSIONS_LINUX
+// These are for compatibility with binaries linked against liblzma that
+// has been patched with xz-5.2.2-compat-libs.patch from RHEL/CentOS 7.
+// Actually that patch didn't create lzma_stream_encoder_mt@XZ_5.2.2
+// but it has been added here anyway since someone might misread the
+// RHEL patch and think both @XZ_5.1.2alpha and @XZ_5.2.2 exist.
+LZMA_SYMVER_API("lzma_stream_encoder_mt@XZ_5.1.2alpha",
+	lzma_ret, lzma_stream_encoder_mt_512a)(
+		lzma_stream *strm, const lzma_mt *options)
+		lzma_nothrow lzma_attr_warn_unused_result
+		__attribute__((__alias__("lzma_stream_encoder_mt_52")));
+
+LZMA_SYMVER_API("lzma_stream_encoder_mt@XZ_5.2.2",
+	lzma_ret, lzma_stream_encoder_mt_522)(
+		lzma_stream *strm, const lzma_mt *options)
+		lzma_nothrow lzma_attr_warn_unused_result
+		__attribute__((__alias__("lzma_stream_encoder_mt_52")));
+
+LZMA_SYMVER_API("lzma_stream_encoder_mt@@XZ_5.2",
+	lzma_ret, lzma_stream_encoder_mt_52)(
+		lzma_stream *strm, const lzma_mt *options)
+		lzma_nothrow lzma_attr_warn_unused_result;
+
+#define lzma_stream_encoder_mt lzma_stream_encoder_mt_52
+#endif
 extern LZMA_API(lzma_ret)
 lzma_stream_encoder_mt(lzma_stream *strm, const lzma_mt *options)
 {
@@ -1093,6 +1118,23 @@ lzma_stream_encoder_mt(lzma_stream *strm, const lzma_mt *options)
 }
 
 
+#ifdef HAVE_SYMBOL_VERSIONS_LINUX
+LZMA_SYMVER_API("lzma_stream_encoder_mt_memusage@XZ_5.1.2alpha",
+	uint64_t, lzma_stream_encoder_mt_memusage_512a)(
+	const lzma_mt *options) lzma_nothrow lzma_attr_pure
+	__attribute__((__alias__("lzma_stream_encoder_mt_memusage_52")));
+
+LZMA_SYMVER_API("lzma_stream_encoder_mt_memusage@XZ_5.2.2",
+	uint64_t, lzma_stream_encoder_mt_memusage_522)(
+	const lzma_mt *options) lzma_nothrow lzma_attr_pure
+	__attribute__((__alias__("lzma_stream_encoder_mt_memusage_52")));
+
+LZMA_SYMVER_API("lzma_stream_encoder_mt_memusage@@XZ_5.2",
+	uint64_t, lzma_stream_encoder_mt_memusage_52)(
+	const lzma_mt *options) lzma_nothrow lzma_attr_pure;
+
+#define lzma_stream_encoder_mt_memusage lzma_stream_encoder_mt_memusage_52
+#endif
 // This function name is a monster but it's consistent with the older
 // monster names. :-( 31 chars is the max that C99 requires so in that
 // sense it's not too long. ;-)