Introduce SNAPPY_ATTRIBUTE_ALWAYS_INLINE.

An internal CL started using ABSL_ATTRIBUTE_ALWAYS_INLINE
from Abseil. This CL introduces equivalent functionality as
SNAPPY_ALWAYS_INLINE.

PiperOrigin-RevId: 306289650

CMakeLists.txt

@@ -103,6 +103,13 @@ int main() {
   return __builtin_ctzll(0);
 }" HAVE_BUILTIN_CTZ)
 
+check_cxx_source_compiles("
+__attribute__((always_inline)) int zero() { return 0; }
+
+int main() {
+  return zero();
+}" HAVE_ATTRIBUTE_ALWAYS_INLINE)
+
 check_cxx_source_compiles("
 #include <tmmintrin.h>
 

cmake/config.h.in

@@ -1,6 +1,9 @@
 #ifndef THIRD_PARTY_SNAPPY_OPENSOURCE_CMAKE_CONFIG_H_
 #define THIRD_PARTY_SNAPPY_OPENSOURCE_CMAKE_CONFIG_H_
 
+/* Define to 1 if the compiler supports __attribute__((always_inline)). */
+#cmakedefine HAVE_ATTRIBUTE_ALWAYS_INLINE 1
+
 /* Define to 1 if the compiler supports __builtin_ctz and friends. */
 #cmakedefine HAVE_BUILTIN_CTZ 1
 

snappy-stubs-internal.h

@@ -37,7 +37,7 @@
 
 #include <cstdint>
 #include <cstring>
-#include <numeric_limits>
+#include <limits>
 #include <string>
 
 #include <assert.h>
@@ -107,6 +107,13 @@
 #define SNAPPY_PREDICT_TRUE(x) x
 #endif
 
+// Inlining hints.
+#ifdef HAVE_ATTRIBUTE_ALWAYS_INLINE
+#define SNAPPY_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline))
+#else
+#define SNAPPY_ATTRIBUTE_ALWAYS_INLINE
+#endif
+
 // This is only used for recomputing the tag byte table used during
 // decompression; for simplicity we just remove it from the open-source
 // version (anyone who wants to regenerate it can just do the call

snappy.cc

@@ -1358,7 +1358,7 @@ class SnappyArrayWriter {
     }
   }
 
-  ABSL_ATTRIBUTE_ALWAYS_INLINE
+  SNAPPY_ATTRIBUTE_ALWAYS_INLINE
   inline bool AppendFromSelf(size_t offset, size_t len, char** op_p) {
     char* const op = *op_p;
     char* const op_end = op + len;