Introduce SLINKY_TRIVIAL_ABI (#479)

https://clang.llvm.org/docs/AttributeReference.html#trivial-abi This PR adds SLINKY_TRIVIAL_ABI and annotates ref_count with it. The binary size (measured internally) impact: libruntime.so: 321K -> 315K, libruntime.a: 413K -> 406K
dsharlet · Nov 2, 2024 · 46195ce · 46195ce
1 parent f93dd94
commit 46195ce
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/base/ref_count.h b/base/ref_count.h
@@ -29,7 +29,7 @@ class ref_counted {
 
 // A smart pointer to a ref_counted base.
 template <typename T>
-class ref_count {
+class SLINKY_TRIVIAL_ABI ref_count {
   T* value;
 
 public:

diff --git a/base/util.h b/base/util.h
@@ -7,6 +7,18 @@ namespace slinky {
 #define SLINKY_ALWAYS_INLINE __attribute__((always_inline))
 #define SLINKY_NO_INLINE __attribute__((noinline))
 
+#if !defined(__has_attribute)
+#define SLINKY_HAS_ATTRIBUTE(x) 0
+#else
+#define SLINKY_HAS_ATTRIBUTE(x) __has_attribute(x)
+#endif
+
+#if SLINKY_HAS_ATTRIBUTE(trivial_abi)
+#define SLINKY_TRIVIAL_ABI __attribute__((trivial_abi))
+#else
+#define SLINKY_TRIVIAL_ABI
+#endif
+
 #ifdef NDEBUG
 // alloca() will cause stack-smashing code to be inserted;
 // while laudable, we use alloca() in time-critical code