[builtins] Better Fuchsia support

Add Fuchsia support to some builtings and avoid building builtins
that are not and will never be used on Fuchsia.

Differential Revision: https://reviews.llvm.org/D34075

llvm-svn: 307832

compiler-rt/lib/builtins/CMakeLists.txt

@@ -44,7 +44,6 @@ set(GENERIC_SOURCES
   ashrti3.c
   bswapdi2.c
   bswapsi2.c
-  clear_cache.c
   clzdi2.c
   clzsi2.c
   clzti2.c
@@ -68,7 +67,6 @@ set(GENERIC_SOURCES
   divti3.c
   divtf3.c
   divxc3.c
-  eprintf.c
   extendsfdf2.c
   extendhfsf2.c
   ffsdi2.c
@@ -191,11 +189,12 @@ option(COMPILER_RT_EXCLUDE_ATOMIC_BUILTIN
   "Skip the atomic builtin (this may be needed if system headers are unavailable)"
   Off)
 
-if(NOT COMPILER_RT_BAREMETAL_BUILD)
+if(NOT FUCHSIA AND NOT COMPILER_RT_BAREMETAL_BUILD)
   set(GENERIC_SOURCES
     ${GENERIC_SOURCES}
     emutls.c 
-    enable_execute_stack.c)
+    enable_execute_stack.c
+    eprintf.c)
 endif()
 
 if(COMPILER_RT_HAS_ATOMIC_KEYWORD AND NOT COMPILER_RT_EXCLUDE_ATOMIC_BUILTIN)
@@ -221,6 +220,12 @@ if (HAVE_UNWIND_H)
       gcc_personality_v0.c)
 endif ()
 
+if (NOT FUCHSIA)
+  set(GENERIC_SOURCES
+    ${GENERIC_SOURCES}
+    clear_cache.c)
+endif()
+
 if (NOT MSVC)
   set(x86_64_SOURCES
       x86_64/chkstk.S

compiler-rt/lib/builtins/int_util.c

@@ -45,6 +45,16 @@ void compilerrt_abort_impl(const char *file, int line, const char *function) {
   __assert_rtn(function, file, line, "libcompiler_rt abort");
 }
 
+#elif __Fuchsia__
+
+#ifndef _WIN32
+__attribute__((weak))
+__attribute__((visibility("hidden")))
+#endif
+void compilerrt_abort_impl(const char *file, int line, const char *function) {
+  __builtin_trap();
+}
+
 #else
 
 /* Get the system definition of abort() */