[RISCV] Add FreeBSD targets

[emaste]

lib/Basic/Targets.cpp

379

My usual pedantic point: let's start these off in alpha order for consistency when additional cases are added

[asb]

This looks good to me, thanks!

[jrtc27]

Sorted OS case statements

lib/Basic/Targets.cpp

TargetInfo *AllocateTarget(const llvm::Triple &Triple,
   case llvm::Triple::nvptx64:
     return new NVPTXTargetInfo(Triple, Opts, /*TargetPointerWidth=*/64);
 
   case llvm::Triple::amdgcn:
   case llvm::Triple::r600:
     return new AMDGPUTargetInfo(Triple, Opts);
 
   case llvm::Triple::riscv32:
-    // TODO: add cases for FreeBSD, NetBSD, RTEMS once tested.
-    if (os == llvm::Triple::Linux)
+    // TODO: add cases for NetBSD, RTEMS once tested.
+    switch (os) {
+    case llvm::Triple::Linux:
       return new LinuxTargetInfo<RISCV32TargetInfo>(Triple, Opts);
+    case llvm::Triple::FreeBSD:
+      return new FreeBSDTargetInfo<RISCV32TargetInfo>(Triple, Opts);
+    default:
       return new RISCV32TargetInfo(Triple, Opts);
+    }
+
   case llvm::Triple::riscv64:
-    // TODO: add cases for FreeBSD, NetBSD, RTEMS once tested.
-    if (os == llvm::Triple::Linux)
+    // TODO: add cases for NetBSD, RTEMS once tested.
+    switch (os) {
+    case llvm::Triple::Linux:
       return new LinuxTargetInfo<RISCV64TargetInfo>(Triple, Opts);
+    case llvm::Triple::FreeBSD:
+      return new FreeBSDTargetInfo<RISCV64TargetInfo>(Triple, Opts);
+    default:
       return new RISCV64TargetInfo(Triple, Opts);
+    }
 
   case llvm::Triple::sparc:
     switch (os) {
     case llvm::Triple::Linux:
       return new LinuxTargetInfo<SparcV8TargetInfo>(Triple, Opts);
     case llvm::Triple::Solaris:
       return new SolarisTargetInfo<SparcV8TargetInfo>(Triple, Opts);
     case llvm::Triple::NetBSD:

lib/Driver/ToolChains/FreeBSD.cpp

case llvm::Triple::mips64:
     break;
   case llvm::Triple::mips64el:
     CmdArgs.push_back("-m");
     if (tools::mips::hasMipsAbiArg(Args, "n32"))
       CmdArgs.push_back("elf32ltsmipn32_fbsd");
     else
       CmdArgs.push_back("elf64ltsmip_fbsd");
     break;
+  case llvm::Triple::riscv32:
+    CmdArgs.push_back("-m");
+    CmdArgs.push_back("elf32lriscv");
+    break;
+  case llvm::Triple::riscv64:
+    CmdArgs.push_back("-m");
+    CmdArgs.push_back("elf64lriscv");
+    break;
   default:
     break;
   }
 
   if (Arg *A = Args.getLastArg(options::OPT_G)) {
     if (ToolChain.getTriple().isMIPS()) {
       StringRef v = A->getValue();
       CmdArgs.push_back(Args.MakeArgString("-G" + v));

test/Driver/freebsd.c

 // CHECK-MIPS64EL-LD: ld{{.*}}" {{.*}} "-m" "elf64ltsmip_fbsd"
 // RUN: %clang -target mips64-freebsd -mabi=n32 %s -### %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-MIPSN32-LD %s
 // CHECK-MIPSN32-LD: ld{{.*}}" {{.*}} "-m" "elf32btsmipn32_fbsd"
 // RUN: %clang -target mips64el-freebsd -mabi=n32 %s -### %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-MIPSN32EL-LD %s
 // CHECK-MIPSN32EL-LD: ld{{.*}}" {{.*}} "-m" "elf32ltsmipn32_fbsd"
 //
+// Check that RISC-V passes the correct linker emulation.
+//
+// RUN: %clang -target riscv32-freebsd %s -### %s 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RV32I-LD %s
+// CHECK-RV32I-LD: ld{{.*}}" {{.*}} "-m" "elf32lriscv"
+// RUN: %clang -target riscv64-freebsd %s -### %s 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RV64I-LD %s
+// CHECK-RV64I-LD: ld{{.*}}" {{.*}} "-m" "elf64lriscv"
+//
 // Check that the new linker flags are passed to FreeBSD
 // RUN: %clang -no-canonical-prefixes -target x86_64-pc-freebsd8 -m32 %s \
 // RUN:   --sysroot=%S/Inputs/multiarch_freebsd64_tree -### 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-LDFLAGS8 %s
 // RUN: %clang -no-canonical-prefixes -target x86_64-pc-freebsd9 -m32 %s \
 // RUN:   --sysroot=%S/Inputs/multiarch_freebsd64_tree -### 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-LDFLAGS9 %s
 // RUN: %clang -no-canonical-prefixes -target x86_64-pc-freebsd10.0 -m32 %s \