[MinGW] Link to correct openmp library

[mstorsjo]

Please add a testcase in test/Driver/, it looks like fopenmp.c there might be a good target to add a few lines in.

[SquallATF]

• add test

[mstorsjo]

LGTM, I can commit it for you on Monday, after giving others a chance to comment.

lib/Driver/ToolChains/MinGW.cpp

if (!Args.hasArg(options::OPT_nodefaultlibs)) {
         CmdArgs.push_back("--start-group");
 
       if (Args.hasArg(options::OPT_fstack_protector) ||
           Args.hasArg(options::OPT_fstack_protector_strong) ||
           Args.hasArg(options::OPT_fstack_protector_all)) {
         CmdArgs.push_back("-lssp_nonshared");
         CmdArgs.push_back("-lssp");
       }
-      if (Args.hasArg(options::OPT_fopenmp))
+
+      if (Args.hasFlag(options::OPT_fopenmp, options::OPT_fopenmp_EQ,
+                       options::OPT_fno_openmp, false)) {
+        switch (TC.getDriver().getOpenMPRuntime(Args)) {
+        case Driver::OMPRT_OMP:
+          CmdArgs.push_back("-lomp");
+          break;
+        case Driver::OMPRT_IOMP5:
+          CmdArgs.push_back("-liomp5md");
+          break;
+        case Driver::OMPRT_GOMP:
           CmdArgs.push_back("-lgomp");
+          break;
+        case Driver::OMPRT_Unknown:
+          // Already diagnosed.
+          break;
+        }
+      }
 
       AddLibGCC(Args, CmdArgs);
 
       if (Args.hasArg(options::OPT_pg))
         CmdArgs.push_back("-lgmon");
 
       if (Args.hasArg(options::OPT_pthread))
         CmdArgs.push_back("-lpthread");

test/Driver/fopenmp.c

 // RUN: %clang -target x86_64-linux-gnu -fopenmp=libomp -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-OPENMP
 // RUN: %clang -target x86_64-linux-gnu -fopenmp=libgomp -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-NO-OPENMP
 // RUN: %clang -target x86_64-linux-gnu -fopenmp=libiomp5 -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-OPENMP
 // RUN: %clang -target x86_64-apple-darwin -fopenmp=libomp -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-OPENMP
 // RUN: %clang -target x86_64-apple-darwin -fopenmp=libgomp -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-NO-OPENMP
 // RUN: %clang -target x86_64-apple-darwin -fopenmp=libiomp5 -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-OPENMP
 // RUN: %clang -target x86_64-freebsd -fopenmp=libomp -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-OPENMP
 // RUN: %clang -target x86_64-freebsd -fopenmp=libgomp -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-NO-OPENMP
 // RUN: %clang -target x86_64-freebsd -fopenmp=libiomp5 -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-OPENMP
 // RUN: %clang -target x86_64-netbsd -fopenmp=libomp -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-OPENMP
 // RUN: %clang -target x86_64-netbsd -fopenmp=libgomp -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-NO-OPENMP
 // RUN: %clang -target x86_64-netbsd -fopenmp=libiomp5 -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-OPENMP
+// RUN: %clang -target x86_64-windows-gnu -fopenmp=libomp -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-OPENMP
+// RUN: %clang -target x86_64-windows-gnu -fopenmp=libgomp -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-NO-OPENMP
+// RUN: %clang -target x86_64-windows-gnu -fopenmp=libiomp5 -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CC1-OPENMP
 //
 // CHECK-CC1-OPENMP: "-cc1"
 // CHECK-CC1-OPENMP: "-fopenmp"
 //
 // CHECK-CC1-NO-OPENMP: "-cc1"
 // 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-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
 //
+// RUN: %clang -target x86_64-windows-gnu -fopenmp=libomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-OMP
+// RUN: %clang -target x86_64-windows-gnu -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-windows-gnu -fopenmp=libiomp5 %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-IOMP5MD
+//
+// RUN: %clang -nostdlib -target x86_64-windows-gnu -fopenmp=libomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-OMP
+// RUN: %clang -nostdlib -target x86_64-windows-gnu -fopenmp=libgomp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-GOMP
+// RUN: %clang -nostdlib -target x86_64-windows-gnu -fopenmp=libiomp5 %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-IOMP5MD
+//
 // CHECK-LD-OMP: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-OMP: "-lomp"
 //
 // 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"
 //
+// CHECK-LD-IOMP5MD: "{{.*}}ld{{(.exe)?}}"
+// CHECK-LD-IOMP5MD: "-liomp5md"
+//
 // CHECK-NO-OMP: "{{.*}}ld{{(.exe)?}}"
 // CHECK-NO-OMP-NOT: "-lomp"
 //
 // CHECK-NO-GOMP: "{{.*}}ld{{(.exe)?}}"
 // CHECK-NO-GOMP-NOT: "-lgomp"
 //
 // CHECK-NO-IOMP5: "{{.*}}ld{{(.exe)?}}"
 // CHECK-NO-IOMP5-NOT: "-liomp5"
 //
+// CHECK-NO-IOMP5MD: "{{.*}}ld{{(.exe)?}}"
+// CHECK-NO-IOMP5MD-NOT: "-liomp5md"
+//
 // We'd like to check that the default is sane, but until we have the ability
 // to *always* semantically analyze OpenMP without always generating runtime
 // calls (in the event of an unsupported runtime), we don't have a good way to
 // test the CC1 invocation. Instead, just ensure we do eventually link *some*
 // OpenMP runtime.
 //
 // RUN: %clang -target x86_64-linux-gnu -fopenmp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-ANY
 // RUN: %clang -target x86_64-darwin -fopenmp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-ANY
 // RUN: %clang -target x86_64-freebsd -fopenmp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-ANY
 // RUN: %clang -target x86_64-netbsd -fopenmp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-ANY
+// RUN: %clang -target x86_64-windows-gnu -fopenmp %s -o %t -### 2>&1 | FileCheck %s --check-prefix=CHECK-LD-ANYMD
 //
 // CHECK-LD-ANY: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-ANY: "-l{{(omp|gomp|iomp5)}}"
+//
+// CHECK-LD-ANYMD: "{{.*}}ld{{(.exe)?}}"
+// CHECK-LD-ANYMD: "-l{{(omp|gomp|iomp5md)}}"