From 5137aa79b9f66e61c5665fb88f8d2e906496cca9 Mon Sep 17 00:00:00 2001
From: Alexey Bataev <a.bataev@hotmail.com>
Date: Fri, 6 Jul 2018 21:13:41 +0000
Subject: [PATCH] [OPENMP] Fix PR38026: Link -latomic when -fopenmp is used.

On Linux atomic constructs in OpenMP require libatomic library. Patch
links libatomic when -fopenmp is used.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@336467 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Driver/ToolChains/Gnu.cpp |  6 +++++-
 test/OpenMP/linking.c         | 16 ++++++++--------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/lib/Driver/ToolChains/Gnu.cpp b/lib/Driver/ToolChains/Gnu.cpp
index 1ecf127c4b..ee3096813e 100644
--- a/lib/Driver/ToolChains/Gnu.cpp
+++ b/lib/Driver/ToolChains/Gnu.cpp
@@ -479,6 +479,7 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
 
       bool WantPthread = Args.hasArg(options::OPT_pthread) ||
                          Args.hasArg(options::OPT_pthreads);
+      bool WantAtomic = false;
 
       // FIXME: Only pass GompNeedsRT = true for platforms with libgomp that
       // require librt. Most modern Linux platforms do, but some may not.
@@ -487,13 +488,16 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                            /* GompNeedsRT= */ true))
         // OpenMP runtimes implies pthreads when using the GNU toolchain.
         // FIXME: Does this really make sense for all GNU toolchains?
-        WantPthread = true;
+        WantAtomic = WantPthread = true;
 
       AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
 
       if (WantPthread && !isAndroid)
         CmdArgs.push_back("-lpthread");
 
+      if (WantAtomic)
+        CmdArgs.push_back("-latomic");
+
       if (Args.hasArg(options::OPT_fsplit_stack))
         CmdArgs.push_back("--wrap=pthread_create");
 
diff --git a/test/OpenMP/linking.c b/test/OpenMP/linking.c
index 802553c1be..e2f83f9571 100644
--- a/test/OpenMP/linking.c
+++ b/test/OpenMP/linking.c
@@ -8,14 +8,14 @@
 // RUN:   | FileCheck --check-prefix=CHECK-LD-32 %s
 // CHECK-LD-32: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-32: "-l[[DEFAULT_OPENMP_LIB:[^"]*]]"
-// CHECK-LD-32: "-lpthread" "-lc"
+// CHECK-LD-32: "-lpthread" "-latomic" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp -target x86_64-unknown-linux -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-64 %s
 // CHECK-LD-64: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-64: "-l[[DEFAULT_OPENMP_LIB:[^"]*]]"
-// CHECK-LD-64: "-lpthread" "-lc"
+// CHECK-LD-64: "-lpthread" "-latomic" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp=libgomp -target i386-unknown-linux -rtlib=platform \
@@ -27,7 +27,7 @@
 // SIMD-ONLY2-NOT: liomp
 // CHECK-GOMP-LD-32: "{{.*}}ld{{(.exe)?}}"
 // CHECK-GOMP-LD-32: "-lgomp" "-lrt"
-// CHECK-GOMP-LD-32: "-lpthread" "-lc"
+// CHECK-GOMP-LD-32: "-lpthread" "-latomic" "-lc"
 
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 -fopenmp-simd -target i386-unknown-linux -rtlib=platform | FileCheck --check-prefix SIMD-ONLY2 %s
 // SIMD-ONLY2-NOT: lgomp
@@ -39,21 +39,21 @@
 // RUN:   | FileCheck --check-prefix=CHECK-GOMP-LD-64 %s
 // CHECK-GOMP-LD-64: "{{.*}}ld{{(.exe)?}}"
 // CHECK-GOMP-LD-64: "-lgomp" "-lrt"
-// CHECK-GOMP-LD-64: "-lpthread" "-lc"
+// CHECK-GOMP-LD-64: "-lpthread" "-latomic" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp -target i386-unknown-linux -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-IOMP5-LD-32 %s
 // CHECK-IOMP5-LD-32: "{{.*}}ld{{(.exe)?}}"
 // CHECK-IOMP5-LD-32: "-l[[DEFAULT_OPENMP_LIB:[^"]*]]"
-// CHECK-IOMP5-LD-32: "-lpthread" "-lc"
+// CHECK-IOMP5-LD-32: "-lpthread" "-latomic" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp -target x86_64-unknown-linux -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-IOMP5-LD-64 %s
 // CHECK-IOMP5-LD-64: "{{.*}}ld{{(.exe)?}}"
 // CHECK-IOMP5-LD-64: "-l[[DEFAULT_OPENMP_LIB:[^"]*]]"
-// CHECK-IOMP5-LD-64: "-lpthread" "-lc"
+// CHECK-IOMP5-LD-64: "-lpthread" "-latomic" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp=lib -target i386-unknown-linux \
@@ -71,7 +71,7 @@
 // RUN:   | FileCheck --check-prefix=CHECK-LD-OVERRIDE-32 %s
 // CHECK-LD-OVERRIDE-32: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-OVERRIDE-32: "-lgomp" "-lrt"
-// CHECK-LD-OVERRIDE-32: "-lpthread" "-lc"
+// CHECK-LD-OVERRIDE-32: "-lpthread" "-latomic" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp -fopenmp=libgomp -target x86_64-unknown-linux \
@@ -79,7 +79,7 @@
 // RUN:   | FileCheck --check-prefix=CHECK-LD-OVERRIDE-64 %s
 // CHECK-LD-OVERRIDE-64: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-OVERRIDE-64: "-lgomp" "-lrt"
-// CHECK-LD-OVERRIDE-64: "-lpthread" "-lc"
+// CHECK-LD-OVERRIDE-64: "-lpthread" "-latomic" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp=libomp -target x86_64-msvc-win32 -rtlib=platform \
-- 
2.40.0