FreeBSD and/or clang build fix. (#1317)

Summary:
clang being more strict with obsolete C++14 api, has
completely disabled them in this context.
Pull Request resolved: https://github.com/facebook/folly/pull/1317

Reviewed By: luciang, markisaa

Differential Revision: D20154780

Pulled By: yfeldblum

fbshipit-source-id: 1ff36fecd3406802c3f393dfdd5dbe2f30656567

folly/Portability.h

@@ -550,3 +550,13 @@ constexpr auto kCpplibVer = 0;
 #define FOLLY_HAS_STRING_VIEW 0
 #endif
 #endif // __has_include
+
+#if defined(__linux__)
+#define FOLLY_ELF_NATIVE_CLASS __ELF_NATIVE_CLASS
+#elif defined(__FreeBSD__)
+#if defined(__LP64__)
+#define FOLLY_ELF_NATIVE_CLASS 64
+#else // __linux__
+#define FOLLY_ELF_NATIVE_CLASS 32
+#endif
+#endif // __linux__

folly/experimental/exception_tracer/ExceptionAbi.h

@@ -26,6 +26,7 @@
 
 namespace __cxxabiv1 {
 
+#if !defined(__FreeBSD__)
 struct __cxa_exception {
   std::type_info* exceptionType;
   void (*exceptionDestructor)(void*);
@@ -52,5 +53,6 @@ extern "C" {
 __cxa_eh_globals* __cxa_get_globals(void) noexcept;
 __cxa_eh_globals* __cxa_get_globals_fast(void) noexcept;
 }
+#endif
 
 } // namespace __cxxabiv1

folly/experimental/exception_tracer/ExceptionTracer.cpp

@@ -16,6 +16,7 @@
 
 #include <folly/experimental/exception_tracer/ExceptionTracer.h>
 
+#include <cstdlib>
 #include <exception>
 #include <iostream>
 
@@ -200,6 +201,7 @@ std::vector<ExceptionInfo> getCurrentExceptions() {
   return exceptions;
 }
 
+#if FOLLY_USE_LIBSTDCPP
 namespace {
 
 std::terminate_handler origTerminate = abort;
@@ -238,6 +240,7 @@ void installHandlers() {
   };
   static Once once;
 }
+#endif
 
 } // namespace exception_tracer
 } // namespace folly

folly/experimental/symbolizer/Dwarf.cpp

@@ -380,7 +380,7 @@ bool Dwarf::Section::next(folly::StringPiece& chunk) {
 }
 
 folly::StringPiece Dwarf::getSection(const char* name) const {
-  const ElfW(Shdr)* elfSection = elf_->getSectionByName(name);
+  const ElfShdr* elfSection = elf_->getSectionByName(name);
   if (!elfSection) {
     return {};
   }

folly/experimental/symbolizer/Elf.cpp

@@ -211,7 +211,7 @@ ElfFile::OpenResult ElfFile::init() noexcept {
 
   auto& elfHeader = this->elfHeader();
 
-#define EXPECTED_CLASS P1(ELFCLASS, __ELF_NATIVE_CLASS)
+#define EXPECTED_CLASS P1(ELFCLASS, FOLLY_ELF_NATIVE_CLASS)
 #define P1(a, b) P2(a, b)
 #define P2(a, b) a##b
   // Validate ELF class (32/64 bits)

folly/experimental/symbolizer/Elf.h

@@ -35,12 +35,21 @@
 namespace folly {
 namespace symbolizer {
 
+#if defined(__linux__)
 using ElfAddr = ElfW(Addr);
 using ElfEhdr = ElfW(Ehdr);
 using ElfOff = ElfW(Off);
 using ElfPhdr = ElfW(Phdr);
 using ElfShdr = ElfW(Shdr);
 using ElfSym = ElfW(Sym);
+#elif defined(__FreeBSD__)
+using ElfAddr = Elf_Addr;
+using ElfEhdr = Elf_Ehdr;
+using ElfOff = Elf_Off;
+using ElfPhdr = Elf_Phdr;
+using ElfShdr = Elf_Shdr;
+using ElfSym = Elf_Sym;
+#endif
 
 /**
  * ELF file parser.

folly/experimental/symbolizer/SignalHandler.cpp

@@ -361,8 +361,15 @@ void dumpSignalInfo(int signum, siginfo_t* siginfo) {
   printDec(getpid());
   print(" (pthread TID ");
   printHex((uint64_t)pthread_self());
+#if defined(__linux__)
   print(") (linux TID ");
   printDec(syscall(__NR_gettid));
+#elif defined(__FreeBSD__)
+  long tid = 0;
+  syscall(432, &tid);
+  print(") (freebsd TID ");
+  printDec(tid);
+#endif
 
   // Kernel-sourced signals don't give us useful info for pid/uid.
   if (siginfo->si_code <= 0) {

folly/experimental/symbolizer/Symbolizer.cpp

@@ -189,7 +189,7 @@ void Symbolizer::symbolize(
 
       // Get the unrelocated, ELF-relative address by normalizing via the
       // address at which the object is loaded.
-      auto const adjusted = addr - lmap->l_addr;
+      auto const adjusted = addr - reinterpret_cast<uintptr_t>(lmap->l_addr);
       size_t numInlined = 0;
       if (elfFile->getSectionContainingAddress(adjusted)) {
         if (mode_ == LocationInfoMode::FULL_WITH_INLINE &&
@@ -374,7 +374,7 @@ void SymbolizePrinter::println(
 namespace {
 
 int getFD(const std::ios& stream) {
-#if defined(__GNUC__) && FOLLY_HAS_RTTI
+#if FOLLY_USE_LIBSTDCPP && FOLLY_HAS_RTTI
   std::streambuf* buf = stream.rdbuf();
   using namespace __gnu_cxx;