From 8ea76fa9b4503847aa0bd784d2a26df5d3429aea Mon Sep 17 00:00:00 2001
From: Jonas Hahnfeld <Hahnfeld@itc.rwth-aachen.de>
Date: Wed, 19 Apr 2017 13:55:39 +0000
Subject: [PATCH] [Driver] Unify linking of OpenMP runtime. NFCI.

While at it, extend test for FreeBSD and check for -lrt iff on Linux.

Differential Revision: https://reviews.llvm.org/D30087

llvm-svn: 300689
---
 clang/lib/Driver/ToolChains/CommonArgs.cpp | 17 +++++++++---
 clang/lib/Driver/ToolChains/CommonArgs.h   |  6 ++--
 clang/lib/Driver/ToolChains/Gnu.cpp        | 32 ++++------------------
 clang/test/Driver/fopenmp.c                | 16 +++++++----
 4 files changed, 33 insertions(+), 38 deletions(-)

diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index e5f4a3b8d6051..cb273300cdc1d 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -426,11 +426,12 @@ void tools::addArchSpecificRPath(const ToolChain &TC, const ArgList &Args,
   }
 }
 
-void tools::addOpenMPRuntime(ArgStringList &CmdArgs, const ToolChain &TC,
-                             const ArgList &Args) {
+bool tools::addOpenMPRuntime(ArgStringList &CmdArgs, const ToolChain &TC,
+                             const ArgList &Args, bool IsOffloadingHost,
+                             bool GompNeedsRT) {
   if (!Args.hasFlag(options::OPT_fopenmp, options::OPT_fopenmp_EQ,
                     options::OPT_fno_openmp, false))
-    return;
+    return false;
 
   switch (TC.getDriver().getOpenMPRuntime(Args)) {
   case Driver::OMPRT_OMP:
@@ -438,16 +439,24 @@ void tools::addOpenMPRuntime(ArgStringList &CmdArgs, const ToolChain &TC,
     break;
   case Driver::OMPRT_GOMP:
     CmdArgs.push_back("-lgomp");
+
+    if (GompNeedsRT)
+      CmdArgs.push_back("-lrt");
     break;
   case Driver::OMPRT_IOMP5:
     CmdArgs.push_back("-liomp5");
     break;
   case Driver::OMPRT_Unknown:
     // Already diagnosed.
-    break;
+    return false;
   }
 
+  if (IsOffloadingHost)
+    CmdArgs.push_back("-lomptarget");
+
   addArchSpecificRPath(TC, Args, CmdArgs);
+
+  return true;
 }
 
 static void addSanitizerRuntime(const ToolChain &TC, const ArgList &Args,
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.h b/clang/lib/Driver/ToolChains/CommonArgs.h
index f5747aa85f221..fdeb6669b0a8d 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.h
+++ b/clang/lib/Driver/ToolChains/CommonArgs.h
@@ -59,8 +59,10 @@ void AddAssemblerKPIC(const ToolChain &ToolChain,
 
 void addArchSpecificRPath(const ToolChain &TC, const llvm::opt::ArgList &Args,
                           llvm::opt::ArgStringList &CmdArgs);
-void addOpenMPRuntime(llvm::opt::ArgStringList &CmdArgs, const ToolChain &TC,
-                      const llvm::opt::ArgList &Args);
+/// Returns true, if an OpenMP runtime has been added.
+bool addOpenMPRuntime(llvm::opt::ArgStringList &CmdArgs, const ToolChain &TC,
+                      const llvm::opt::ArgList &Args,
+                      bool IsOffloadingHost = false, bool GompNeedsRT = false);
 
 llvm::opt::Arg *getLastProfileUseArg(const llvm::opt::ArgList &Args);
 llvm::opt::Arg *getLastProfileSampleUseArg(const llvm::opt::ArgList &Args);
diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
index 165439538ebaa..313bf38c2860a 100644
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -586,37 +586,15 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
       bool WantPthread = Args.hasArg(options::OPT_pthread) ||
                          Args.hasArg(options::OPT_pthreads);
 
-      if (Args.hasFlag(options::OPT_fopenmp, options::OPT_fopenmp_EQ,
-                       options::OPT_fno_openmp, false)) {
+      // FIXME: Only pass GompNeedsRT = true for platforms with libgomp that
+      // require librt. Most modern Linux platforms do, but some may not.
+      if (addOpenMPRuntime(CmdArgs, ToolChain, Args,
+                           JA.isHostOffloading(Action::OFK_OpenMP),
+                           /* GompNeedsRT= */ true))
         // OpenMP runtimes implies pthreads when using the GNU toolchain.
         // FIXME: Does this really make sense for all GNU toolchains?
         WantPthread = true;
 
-        // Also link the particular OpenMP runtimes.
-        switch (ToolChain.getDriver().getOpenMPRuntime(Args)) {
-        case Driver::OMPRT_OMP:
-          CmdArgs.push_back("-lomp");
-          break;
-        case Driver::OMPRT_GOMP:
-          CmdArgs.push_back("-lgomp");
-
-          // FIXME: Exclude this for platforms with libgomp that don't require
-          // librt. Most modern Linux platforms require it, but some may not.
-          CmdArgs.push_back("-lrt");
-          break;
-        case Driver::OMPRT_IOMP5:
-          CmdArgs.push_back("-liomp5");
-          break;
-        case Driver::OMPRT_Unknown:
-          // Already diagnosed.
-          break;
-        }
-        if (JA.isHostOffloading(Action::OFK_OpenMP))
-          CmdArgs.push_back("-lomptarget");
-
-        addArchSpecificRPath(ToolChain, Args, CmdArgs);
-      }
-
       AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
 
       if (WantPthread && !isAndroid)
diff --git a/clang/test/Driver/fopenmp.c b/clang/test/Driver/fopenmp.c
index ea4284ef6e1b0..ac0f1b44cba30 100644
--- a/clang/test/Driver/fopenmp.c
+++ b/clang/test/Driver/fopenmp.c
@@ -18,7 +18,7 @@
 // CHECK-CC1-NO-OPENMP-NOT: "-fopenmp"
 //
 // RUN: %clang -target x86_64-linux-gnu -fopenmp=libomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-OMP
-// RUN: %clang -target x86_64-linux-gnu -fopenmp=libgomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-GOMP
+// RUN: %clang -target x86_64-linux-gnu -fopenmp=libgomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-GOMP --check-prefix=CHECK-LD-GOMP-RT
 // RUN: %clang -target x86_64-linux-gnu -fopenmp=libiomp5 %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-IOMP5
 //
 // RUN: %clang -nostdlib -target x86_64-linux-gnu -fopenmp=libomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-OMP
@@ -26,21 +26,25 @@
 // RUN: %clang -nostdlib -target x86_64-linux-gnu -fopenmp=libiomp5 %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-IOMP5
 //
 // RUN: %clang -target x86_64-darwin -fopenmp=libomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-OMP
-// RUN: %clang -target x86_64-darwin -fopenmp=libgomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-GOMP
+// RUN: %clang -target x86_64-darwin -fopenmp=libgomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-GOMP --check-prefix=CHECK-LD-GOMP-NO-RT
 // RUN: %clang -target x86_64-darwin -fopenmp=libiomp5 %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-IOMP5
 //
 // RUN: %clang -nostdlib -target x86_64-darwin -fopenmp=libomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-OMP
 // RUN: %clang -nostdlib -target x86_64-darwin -fopenmp=libgomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-GOMP
 // RUN: %clang -nostdlib -target x86_64-darwin -fopenmp=libiomp5 %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-IOMP5
 //
-// RUN: %clang -target x86_64-netbsd -fopenmp=libomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-OMP
-// RUN: %clang -target x86_64-netbsd -fopenmp=libgomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-GOMP
-// RUN: %clang -target x86_64-netbsd -fopenmp=libiomp5 %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-IOMP5
+// RUN: %clang -target x86_64-freebsd -fopenmp=libomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-OMP
+// RUN: %clang -target x86_64-freebsd -fopenmp=libgomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-GOMP --check-prefix=CHECK-LD-GOMP-NO-RT
+// RUN: %clang -target x86_64-freebsd -fopenmp=libiomp5 %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-IOMP5
 //
 // RUN: %clang -nostdlib -target x86_64-freebsd -fopenmp=libomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-OMP
 // RUN: %clang -nostdlib -target x86_64-freebsd -fopenmp=libgomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-GOMP
 // RUN: %clang -nostdlib -target x86_64-freebsd -fopenmp=libiomp5 %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-IOMP5
 //
+// RUN: %clang -target x86_64-netbsd -fopenmp=libomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-OMP
+// RUN: %clang -target x86_64-netbsd -fopenmp=libgomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-GOMP --check-prefix=CHECK-LD-GOMP-NO-RT
+// RUN: %clang -target x86_64-netbsd -fopenmp=libiomp5 %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-IOMP5
+//
 // RUN: %clang -nostdlib -target x86_64-netbsd -fopenmp=libomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-OMP
 // RUN: %clang -nostdlib -target x86_64-netbsd -fopenmp=libgomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-GOMP
 // RUN: %clang -nostdlib -target x86_64-netbsd -fopenmp=libiomp5 %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-IOMP5
@@ -50,6 +54,8 @@
 //
 // CHECK-LD-GOMP: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-GOMP: "-lgomp"
+// CHECK-LD-GOMP-RT: "-lrt"
+// CHECK-LD-GOMP-NO-RT-NOT: "-lrt"
 //
 // CHECK-LD-IOMP5: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-IOMP5: "-liomp5"