Make -DCMAKE_INTERPROCEDURAL_OPTIMIZATION Enable LTO

CMakeLists.txt

@@ -56,7 +56,7 @@ STATIC_BUILD_WITH_DYNAMIC_STDLIB." OFF)
 OPTION (STATIC_BUILD_WITH_DYNAMIC_STDLIB "Build a (mostly) statically linked release binary. \
 Glibc and C++ standard library is linked dynamically." OFF)
 
-if (STATIC_BUILD_WITH_DYNAMIC_GLIBC OR STATIC_BUILD_WITH_DYNAMIC_STDLIB)
+if (STATIC_BUILD_WITH_DYNAMIC_GLIBC OR STATIC_BUILD_WITH_DYNAMIC_STDLIB OR CMAKE_INTERPROCEDURAL_OPTIMIZATION)
     # We want to optimize the binary size for a static release binary by default.
     set (_ENABLE_LTO_DEFAULT ON)
 else()

lib/gc.cpp

@@ -81,6 +81,33 @@ static void maybe_initialize_gc() {
     }
 }
 
+#ifdef __GLIBC__
+#define GNOEXCEPT __THROW
+#else
+#define GNOEXCEPT
+#endif
+void *operator new(std::size_t size) __attribute__((used));
+void *operator new(std::size_t size, const std::nothrow_t &) noexcept __attribute__((used));
+void *operator new(std::size_t size, std::align_val_t alignment) __attribute__((used));
+void *operator new(std::size_t size, std::align_val_t alignment, const std::nothrow_t &) noexcept __attribute__((used));
+void operator delete(void *p) noexcept __attribute__((used));
+void operator delete(void *p, std::size_t /*size*/) noexcept __attribute__((used));
+void operator delete(void *p, std::size_t, std::align_val_t) noexcept __attribute__((used));
+void *operator new[](std::size_t size) __attribute__((used));
+void *operator new[](std::size_t size, std::align_val_t alignment) __attribute__((used));
+void *operator new[](std::size_t size, const std::nothrow_t &tag) noexcept __attribute__((used));
+void *operator new[](std::size_t size, std::align_val_t alignment,
+                     const std::nothrow_t &tag) noexcept __attribute__((used));
+void operator delete[](void *p) noexcept __attribute__((used));
+void operator delete[](void *p, std::size_t) noexcept __attribute__((used));
+void operator delete[](void *p, std::align_val_t) noexcept __attribute__((used));
+void operator delete[](void *p, std::size_t, std::align_val_t) noexcept __attribute__((used));
+void *realloc(void *ptr, size_t size) GNOEXCEPT __attribute__((used));
+void *malloc(size_t size) GNOEXCEPT __attribute__((used));
+void free(void *ptr) GNOEXCEPT __attribute__((used));
+void *calloc(size_t size, size_t elsize) GNOEXCEPT __attribute__((used));
+int posix_memalign(void **memptr, size_t alignment, size_t size) GNOEXCEPT  __attribute__((used));
+
 void *operator new(std::size_t size) {
     TRACE_ALLOC(size)
 
@@ -226,7 +253,7 @@ void raw_free(void *ptr) {
 
 }  // namespace
 
-void *realloc(void *ptr, size_t size) {
+void *realloc(void *ptr, size_t size) GNOEXCEPT {
     if (!done_init) {
         if (started_init) {
             // called from within GC_INIT, so we can't call it again.  Fall back to using
@@ -259,16 +286,16 @@ void *realloc(void *ptr, size_t size) {
 // IMPORTANT: do not simplify this to realloc(nullptr, size)
 // As it could be optimized to malloc(size) call causing
 // infinite loops
-void *malloc(size_t size) {
+void *malloc(size_t size) GNOEXCEPT {
     if (!done_init) return realloc(nullptr, size);
 
     TRACE_ALLOC(size)
     return GC_malloc(size);
 }
-void free(void *ptr) {
+void free(void *ptr) GNOEXCEPT {
     if (done_init && GC_is_heap_ptr(ptr)) GC_free(ptr);
 }
-void *calloc(size_t size, size_t elsize) {
+void *calloc(size_t size, size_t elsize) GNOEXCEPT {
     size *= elsize;
     void *rv = malloc(size);
     if (rv) memset(rv, 0, size);