[runtimes] Support ELF dependent libraries feature

As of r360984, LLD supports dependent libraries feature for ELF.
libunwind, libc++abi and libc++ have library dependencies: libdl librt
and libpthread, which means that when libunwind and libc++ are being
statically linked (using -static-libstdc++ flag), user has to manually
specify -ldl -lpthread which is onerous.

This change includes the lib pragma to specify the library dependencies
directly in the source that uses those libraries. This doesn't make any
difference when using linkers that don't support dependent libraries.
However, when using LLD that has dependent libraries feature, users no
longer have to manually specifying library dependencies when using
static linking, linker will pick the library automatically.

Differential Revision: https://reviews.llvm.org/D62090

llvm-svn: 362048

15 files changed, 63 insertions, 0 deletions

diff --git a/libcxx/src/algorithm.cpp b/libcxx/src/algorithm.cpp
index 28e452f52df..5ce2a23b464 100644
--- a/libcxx/src/algorithm.cpp
+++ b/libcxx/src/algorithm.cpp
@@ -8,7 +8,12 @@
 
 #include "algorithm"
 #include "random"
+#ifndef _LIBCPP_HAS_NO_THREADS
 #include "mutex"
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+#endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
diff --git a/libcxx/src/chrono.cpp b/libcxx/src/chrono.cpp
index c1eb67b61d7..a2f88c94c07 100644
--- a/libcxx/src/chrono.cpp
+++ b/libcxx/src/chrono.cpp
@@ -37,6 +37,10 @@
 #endif
 #endif
 
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "rt")
+#endif
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 namespace chrono
diff --git a/libcxx/src/condition_variable.cpp b/libcxx/src/condition_variable.cpp
index 4022ff2e9ad..69264c680d9 100644
--- a/libcxx/src/condition_variable.cpp
+++ b/libcxx/src/condition_variable.cpp
@@ -15,6 +15,10 @@
 #include "system_error"
 #include "__undef_macros"
 
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 condition_variable::~condition_variable()
diff --git a/libcxx/src/debug.cpp b/libcxx/src/debug.cpp
index 7fdf90c37d9..95024131011 100644
--- a/libcxx/src/debug.cpp
+++ b/libcxx/src/debug.cpp
@@ -13,7 +13,12 @@
 #include "string"
 #include "cstdio"
 #include "__hash_table"
+#ifndef _LIBCPP_HAS_NO_THREADS
 #include "mutex"
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+#endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
diff --git a/libcxx/src/experimental/memory_resource.cpp b/libcxx/src/experimental/memory_resource.cpp
index 22bc12c1005..84c95080496 100644
--- a/libcxx/src/experimental/memory_resource.cpp
+++ b/libcxx/src/experimental/memory_resource.cpp
@@ -12,6 +12,9 @@
 #include "atomic"
 #elif !defined(_LIBCPP_HAS_NO_THREADS)
 #include "mutex"
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
diff --git a/libcxx/src/filesystem/operations.cpp b/libcxx/src/filesystem/operations.cpp
index 5ba979ca905..319d9f65d73 100644
--- a/libcxx/src/filesystem/operations.cpp
+++ b/libcxx/src/filesystem/operations.cpp
@@ -44,6 +44,10 @@
 #include <sys/time.h> // for gettimeofday and timeval
 #endif                // !defined(CLOCK_REALTIME)
 
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "rt")
+#endif
+
 #if defined(_LIBCPP_COMPILER_GCC)
 #if _GNUC_VER < 500
 #pragma GCC diagnostic ignored "-Wmissing-field-initializers"
diff --git a/libcxx/src/memory.cpp b/libcxx/src/memory.cpp
index 8b05c3f1649..6df7226b357 100644
--- a/libcxx/src/memory.cpp
+++ b/libcxx/src/memory.cpp
@@ -10,6 +10,9 @@
 #ifndef _LIBCPP_HAS_NO_THREADS
 #include "mutex"
 #include "thread"
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
 #endif
 #include "include/atomic_support.h"
 
diff --git a/libcxx/src/mutex.cpp b/libcxx/src/mutex.cpp
index cecb89b3399..d100f2df233 100644
--- a/libcxx/src/mutex.cpp
+++ b/libcxx/src/mutex.cpp
@@ -12,6 +12,12 @@
 #include "include/atomic_support.h"
 #include "__undef_macros"
 
+#ifndef _LIBCPP_HAS_NO_THREADS
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+#endif
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 #ifndef _LIBCPP_HAS_NO_THREADS
 
diff --git a/libcxx/src/shared_mutex.cpp b/libcxx/src/shared_mutex.cpp
index e918e1bdf60..3f1aecfdfe1 100644
--- a/libcxx/src/shared_mutex.cpp
+++ b/libcxx/src/shared_mutex.cpp
@@ -10,6 +10,9 @@
 #ifndef _LIBCPP_HAS_NO_THREADS
 
 #include "shared_mutex"
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
diff --git a/libcxx/src/thread.cpp b/libcxx/src/thread.cpp
index 29b06fdf660..92690f66798 100644
--- a/libcxx/src/thread.cpp
+++ b/libcxx/src/thread.cpp
@@ -35,6 +35,10 @@
 #include <windows.h>
 #endif
 
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 thread::~thread()
diff --git a/libcxxabi/src/cxa_guard_impl.h b/libcxxabi/src/cxa_guard_impl.h
index 412099e6f4e..bd6b15fce6a 100644
--- a/libcxxabi/src/cxa_guard_impl.h
+++ b/libcxxabi/src/cxa_guard_impl.h
@@ -49,6 +49,11 @@
 
 #include <stdlib.h>
 #include <__threading_support>
+#ifndef _LIBCXXABI_HAS_NO_THREADS
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+#endif
 
 // To make testing possible, this header is included from both cxa_guard.cpp
 // and a number of tests.
diff --git a/libcxxabi/src/cxa_thread_atexit.cpp b/libcxxabi/src/cxa_thread_atexit.cpp
index da1df861708..38787f18fe3 100644
--- a/libcxxabi/src/cxa_thread_atexit.cpp
+++ b/libcxxabi/src/cxa_thread_atexit.cpp
@@ -9,6 +9,12 @@
 #include "abort_message.h"
 #include "cxxabi.h"
 #include <__threading_support>
+#ifndef _LIBCXXABI_HAS_NO_THREADS
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+#endif
+
 #include <cstdlib>
 
 namespace __cxxabiv1 {
diff --git a/libcxxabi/src/fallback_malloc.cpp b/libcxxabi/src/fallback_malloc.cpp
index 8ec1eeefd84..bae0fa4ac23 100644
--- a/libcxxabi/src/fallback_malloc.cpp
+++ b/libcxxabi/src/fallback_malloc.cpp
@@ -12,6 +12,11 @@
 #include "fallback_malloc.h"
 
 #include <__threading_support>
+#ifndef _LIBCXXABI_HAS_NO_THREADS
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
+#endif
 
 #include <cstdlib> // for malloc, calloc, free
 #include <cstring> // for memset
diff --git a/libunwind/src/AddressSpace.hpp b/libunwind/src/AddressSpace.hpp
index fb370ad1e79..66439530309 100644
--- a/libunwind/src/AddressSpace.hpp
+++ b/libunwind/src/AddressSpace.hpp
@@ -27,6 +27,9 @@
 
 #if _LIBUNWIND_USE_DLADDR
 #include <dlfcn.h>
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "dl")
+#endif
 #endif
 
 #ifdef __APPLE__
diff --git a/libunwind/src/RWMutex.hpp b/libunwind/src/RWMutex.hpp
index 7a08bb2af32..4f234a77edf 100644
--- a/libunwind/src/RWMutex.hpp
+++ b/libunwind/src/RWMutex.hpp
@@ -17,6 +17,9 @@
 #include <windows.h>
 #elif !defined(_LIBUNWIND_HAS_NO_THREADS)
 #include <pthread.h>
+#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#pragma comment(lib, "pthread")
+#endif
 #endif
 
 namespace libunwind {