Cut config-time detection of cplus_demangle_v3_callback

Summary: [Folly] Cut config-time detection of `cplus_demangle_v3_callback` and the forward declarations and copy-pasting symbols, replacing them with `__has_include(<demangle.h>)`.

Reviewed By: Orvid

Differential Revision: D9287760

fbshipit-source-id: 4464ec22dd6f96cf081cda6051bebe4d41813390

CMake/FollyConfigChecks.cmake

@@ -74,11 +74,6 @@ check_symbol_exists(preadv sys/uio.h FOLLY_HAVE_PREADV)
 check_symbol_exists(pwritev sys/uio.h FOLLY_HAVE_PWRITEV)
 check_symbol_exists(clock_gettime time.h FOLLY_HAVE_CLOCK_GETTIME)
 
-
-check_function_exists(
-  cplus_demangle_v3_callback
-  FOLLY_HAVE_CPLUS_DEMANGLE_V3_CALLBACK
-)
 check_function_exists(malloc_usable_size FOLLY_HAVE_MALLOC_USABLE_SIZE)
 
 set(CMAKE_REQUIRED_FLAGS "${FOLLY_ORIGINAL_CMAKE_REQUIRED_FLAGS}")

CMake/folly-config.h.cmake

@@ -45,7 +45,6 @@
 #cmakedefine FOLLY_HAVE_PREADV 1
 #cmakedefine FOLLY_HAVE_PWRITEV 1
 #cmakedefine FOLLY_HAVE_CLOCK_GETTIME 1
-#cmakedefine FOLLY_HAVE_CPLUS_DEMANGLE_V3_CALLBACK 1
 #cmakedefine FOLLY_HAVE_OPENSSL_ASN1_TIME_DIFF 1
 
 #cmakedefine FOLLY_HAVE_IFUNC 1

folly/Demangle.cpp

@@ -19,43 +19,18 @@
 #include <algorithm>
 #include <cstring>
 
+#include <folly/detail/Demangle.h>
 #include <folly/portability/Config.h>
 
-#if FOLLY_HAVE_CPLUS_DEMANGLE_V3_CALLBACK
-#include <cxxabi.h>
+#if FOLLY_DETAIL_HAVE_DEMANGLE_H
 
-// From libiberty
-//
-// __attribute__((__weak__)) doesn't work, because cplus_demangle_v3_callback
-// is exported by an object file in libiberty.a, and the ELF spec says
-// "The link editor does not extract archive members to resolve undefined weak
-// symbols" (but, interestingly enough, will resolve undefined weak symbols
-// with definitions from archive members that were extracted in order to
-// resolve an undefined global (strong) symbol)
-
-# ifndef DMGL_NO_OPTS
-#  define FOLLY_DEFINED_DMGL 1
-#  define DMGL_NO_OPTS    0          /* For readability... */
-#  define DMGL_PARAMS     (1 << 0)   /* Include function args */
-#  define DMGL_ANSI       (1 << 1)   /* Include const, volatile, etc */
-#  define DMGL_JAVA       (1 << 2)   /* Demangle as Java rather than C++. */
-#  define DMGL_VERBOSE    (1 << 3)   /* Include implementation details.  */
-#  define DMGL_TYPES      (1 << 4)   /* Also try to demangle type encodings.  */
-#  define DMGL_RET_POSTFIX (1 << 5)  /* Print function return types (when
-                                        present) after function signature */
-# endif
-
-extern "C" int cplus_demangle_v3_callback(
-    const char* mangled,
-    int options,  // We use DMGL_PARAMS | DMGL_TYPES, aka 0x11
-    void (*callback)(const char*, size_t, void*),
-    void* arg);
+#include <cxxabi.h>
 
 #endif
 
 namespace folly {
 
-#if FOLLY_HAVE_CPLUS_DEMANGLE_V3_CALLBACK
+#if FOLLY_DETAIL_HAVE_DEMANGLE_H
 
 fbstring demangle(const char* name) {
 #ifdef FOLLY_DEMANGLE_MAX_SYMBOL_SIZE
@@ -120,11 +95,8 @@ size_t demangle(const char* name, char* out, size_t outSize) {
   dbuf.total = 0;
 
   // Unlike most library functions, this returns 1 on success and 0 on failure
-  int status = cplus_demangle_v3_callback(
-      name,
-      DMGL_PARAMS | DMGL_ANSI | DMGL_TYPES,
-      demangleCallback,
-      &dbuf);
+  int status =
+      detail::cplus_demangle_v3_callback_wrapper(name, demangleCallback, &dbuf);
   if (status == 0) {  // failed, return original
     return folly::strlcpy(out, name, outSize);
   }

folly/Makefile.am

@@ -86,6 +86,7 @@ nobase_follyinclude_HEADERS = \
 	detail/AtFork.h \
 	detail/AtomicHashUtils.h \
 	detail/AtomicUnorderedMapUtils.h \
+	detail/Demangle.h \
 	detail/DiscriminatedPtrDetail.h \
 	detail/FileUtilDetail.h \
 	detail/FingerprintPolynomial.h \
@@ -533,6 +534,7 @@ libfollybasesse42_la_SOURCES = \
 libfollybase_la_SOURCES = \
 	Conv.cpp \
 	Demangle.cpp \
+	detail/Demangle.cpp \
 	detail/RangeCommon.cpp \
 	Format.cpp \
 	FormatArg.cpp \

folly/detail/Demangle.cpp

+/*
+ * Copyright 2018-present Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <folly/detail/Demangle.h>
+
+// Do not include <libiberty.h> (binutils) and <string.h> (glibc) in the same
+// translation unit since they contain conflicting declarations for the symbol
+// `basename`.
+//
+// So we extract the inclusion of `<demangle.h>` which includes `<libiberty.h>`
+// to here, isolating it.
+#if FOLLY_DETAIL_HAVE_DEMANGLE_H
+#include <demangle.h>
+#endif
+
+namespace folly {
+namespace detail {
+
+int cplus_demangle_v3_callback_wrapper(
+    char const* const mangled,
+    void (*const cbref)(char const*, std::size_t, void*),
+    void* const opaque) {
+#if FOLLY_DETAIL_HAVE_DEMANGLE_H
+  auto const options = DMGL_PARAMS | DMGL_ANSI | DMGL_TYPES;
+  return cplus_demangle_v3_callback(mangled, options, cbref, opaque);
+#else
+  return 0;
+#endif
+}
+
+} // namespace detail
+} // namespace folly

folly/detail/Demangle.h

+/*
+ * Copyright 2018-present Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <cstddef>
+
+#if __has_include(<demangle.h>)
+#define FOLLY_DETAIL_HAVE_DEMANGLE_H 1
+#else
+#define FOLLY_DETAIL_HAVE_DEMANGLE_H 0
+#endif
+
+namespace folly {
+namespace detail {
+
+extern int cplus_demangle_v3_callback_wrapper(
+    char const* mangled,
+    void (*cbref)(char const*, std::size_t, void*),
+    void* opaque);
+
+} // namespace detail
+} // namespace folly

folly/test/DemangleTest.cpp

@@ -16,6 +16,7 @@
 
 #include <folly/Demangle.h>
 
+#include <folly/detail/Demangle.h>
 #include <folly/portability/GTest.h>
 
 using folly::demangle;
@@ -25,7 +26,7 @@ struct ThisIsAVeryLongStructureName {
 };
 } // namespace folly_test
 
-#if FOLLY_HAVE_CPLUS_DEMANGLE_V3_CALLBACK
+#if FOLLY_DETAIL_HAVE_DEMANGLE_H
 TEST(Demangle, demangle) {
   char expected[] = "folly_test::ThisIsAVeryLongStructureName";
   EXPECT_STREQ(
@@ -81,7 +82,7 @@ TEST(Demangle, LongSymbolFallback) {
 }
 #endif // defined(FOLLY_DEMANGLE_MAX_SYMBOL_SIZE)
 
-#endif // FOLLY_HAVE_CPLUS_DEMANGLE_V3_CALLBACK
+#endif // FOLLY_DETAIL_HAVE_DEMANGLE_H
 
 TEST(Demangle, strlcpy) {
   char buf[6];