Add Clang driver flags equivalent to cl's /MD, /MT, /MDd, /MTd.

This will allow selecting the MS C runtime library without having to use
cc1 flags.

Differential Revision: https://reviews.llvm.org/D133457

clang/include/clang/Driver/Options.td

@@ -2211,6 +2211,14 @@ def fms_compatibility_version
       HelpText<"Dot-separated value representing the Microsoft compiler "
                "version number to report in _MSC_VER (0 = don't define it "
                "(default))">;
+def fms_runtime_lib_EQ : Joined<["-"], "fms-runtime-lib=">, Group<f_Group>,
+  Flags<[NoXarchOption, CoreOption]>, Values<"static,static_dbg,dll,dll_dbg">,
+  HelpText<"Select Windows run-time library">,
+  DocBrief<[{
+Specify Visual Studio C runtime library. "static" and "static_dbg" correspond
+to the cl flags /MT and /MTd which use the multithread, static version. "dll"
+and "dll_dbg" correspond to the cl flags /MD and /MDd which use the multithread,
+dll version.}]>;
 defm delayed_template_parsing : BoolFOption<"delayed-template-parsing",
   LangOpts<"DelayedTemplateParsing">, DefaultFalse,
   PosFlag<SetTrue, [CC1Option], "Parse templated function definitions at the end of the translation unit">,

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4437,6 +4437,71 @@ static void renderDebugOptions(const ToolChain &TC, const Driver &D,
   RenderDebugInfoCompressionArgs(Args, CmdArgs, D, TC);
 }
 
+static void ProcessVSRuntimeLibrary(const ArgList &Args,
+                                    ArgStringList &CmdArgs) {
+  unsigned RTOptionID = options::OPT__SLASH_MT;
+
+  if (Args.hasArg(options::OPT__SLASH_LDd))
+    // The /LDd option implies /MTd. The dependent lib part can be overridden,
+    // but defining _DEBUG is sticky.
+    RTOptionID = options::OPT__SLASH_MTd;
+
+  if (Arg *A = Args.getLastArg(options::OPT__SLASH_M_Group))
+    RTOptionID = A->getOption().getID();
+
+  if (Arg *A = Args.getLastArg(options::OPT_fms_runtime_lib_EQ)) {
+    RTOptionID = llvm::StringSwitch<unsigned>(A->getValue())
+                     .Case("static", options::OPT__SLASH_MT)
+                     .Case("static_dbg", options::OPT__SLASH_MTd)
+                     .Case("dll", options::OPT__SLASH_MD)
+                     .Case("dll_dbg", options::OPT__SLASH_MDd)
+                     .Default(options::OPT__SLASH_MT);
+  }
+
+  StringRef FlagForCRT;
+  switch (RTOptionID) {
+  case options::OPT__SLASH_MD:
+    if (Args.hasArg(options::OPT__SLASH_LDd))
+      CmdArgs.push_back("-D_DEBUG");
+    CmdArgs.push_back("-D_MT");
+    CmdArgs.push_back("-D_DLL");
+    FlagForCRT = "--dependent-lib=msvcrt";
+    break;
+  case options::OPT__SLASH_MDd:
+    CmdArgs.push_back("-D_DEBUG");
+    CmdArgs.push_back("-D_MT");
+    CmdArgs.push_back("-D_DLL");
+    FlagForCRT = "--dependent-lib=msvcrtd";
+    break;
+  case options::OPT__SLASH_MT:
+    if (Args.hasArg(options::OPT__SLASH_LDd))
+      CmdArgs.push_back("-D_DEBUG");
+    CmdArgs.push_back("-D_MT");
+    CmdArgs.push_back("-flto-visibility-public-std");
+    FlagForCRT = "--dependent-lib=libcmt";
+    break;
+  case options::OPT__SLASH_MTd:
+    CmdArgs.push_back("-D_DEBUG");
+    CmdArgs.push_back("-D_MT");
+    CmdArgs.push_back("-flto-visibility-public-std");
+    FlagForCRT = "--dependent-lib=libcmtd";
+    break;
+  default:
+    llvm_unreachable("Unexpected option ID.");
+  }
+
+  if (Args.hasArg(options::OPT__SLASH_Zl)) {
+    CmdArgs.push_back("-D_VC_NODEFAULTLIB");
+  } else {
+    CmdArgs.push_back(FlagForCRT.data());
+
+    // This provides POSIX compatibility (maps 'open' to '_open'), which most
+    // users want.  The /Za flag to cl.exe turns this off, but it's not
+    // implemented in clang.
+    CmdArgs.push_back("--dependent-lib=oldnames");
+  }
+}
+
 void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                          const InputInfo &Output, const InputInfoList &Inputs,
                          const ArgList &Args, const char *LinkingOutput) const {
@@ -6478,6 +6543,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   if (IsMSVCCompat)
     CmdArgs.push_back("-fms-compatibility");
 
+  if (Triple.isWindowsMSVCEnvironment() && !D.IsCLMode())
+    ProcessVSRuntimeLibrary(Args, CmdArgs);
+
   // Handle -fgcc-version, if present.
   VersionTuple GNUCVer;
   if (Arg *A = Args.getLastArg(options::OPT_fgnuc_version_EQ)) {
@@ -7528,59 +7596,9 @@ void Clang::AddClangCLArgs(const ArgList &Args, types::ID InputType,
                            ArgStringList &CmdArgs,
                            codegenoptions::DebugInfoKind *DebugInfoKind,
                            bool *EmitCodeView) const {
-  unsigned RTOptionID = options::OPT__SLASH_MT;
   bool isNVPTX = getToolChain().getTriple().isNVPTX();
 
-  if (Args.hasArg(options::OPT__SLASH_LDd))
+  ProcessVSRuntimeLibrary(Args, CmdArgs);
-    // The /LDd option implies /MTd. The dependent lib part can be overridden,
-    // but defining _DEBUG is sticky.
-    RTOptionID = options::OPT__SLASH_MTd;
-
-  if (Arg *A = Args.getLastArg(options::OPT__SLASH_M_Group))
-    RTOptionID = A->getOption().getID();
-
-  StringRef FlagForCRT;
-  switch (RTOptionID) {
-  case options::OPT__SLASH_MD:
-    if (Args.hasArg(options::OPT__SLASH_LDd))
-      CmdArgs.push_back("-D_DEBUG");
-    CmdArgs.push_back("-D_MT");
-    CmdArgs.push_back("-D_DLL");
-    FlagForCRT = "--dependent-lib=msvcrt";
-    break;
-  case options::OPT__SLASH_MDd:
-    CmdArgs.push_back("-D_DEBUG");
-    CmdArgs.push_back("-D_MT");
-    CmdArgs.push_back("-D_DLL");
-    FlagForCRT = "--dependent-lib=msvcrtd";
-    break;
-  case options::OPT__SLASH_MT:
-    if (Args.hasArg(options::OPT__SLASH_LDd))
-      CmdArgs.push_back("-D_DEBUG");
-    CmdArgs.push_back("-D_MT");
-    CmdArgs.push_back("-flto-visibility-public-std");
-    FlagForCRT = "--dependent-lib=libcmt";
-    break;
-  case options::OPT__SLASH_MTd:
-    CmdArgs.push_back("-D_DEBUG");
-    CmdArgs.push_back("-D_MT");
-    CmdArgs.push_back("-flto-visibility-public-std");
-    FlagForCRT = "--dependent-lib=libcmtd";
-    break;
-  default:
-    llvm_unreachable("Unexpected option ID.");
-  }
-
-  if (Args.hasArg(options::OPT__SLASH_Zl)) {
-    CmdArgs.push_back("-D_VC_NODEFAULTLIB");
-  } else {
-    CmdArgs.push_back(FlagForCRT.data());
-
-    // This provides POSIX compatibility (maps 'open' to '_open'), which most
-    // users want.  The /Za flag to cl.exe turns this off, but it's not
-    // implemented in clang.
-    CmdArgs.push_back("--dependent-lib=oldnames");
-  }
 
   if (Arg *ShowIncludes =
           Args.getLastArg(options::OPT__SLASH_showIncludes,

clang/test/Driver/cl-runtime-flags.c

@@ -10,6 +10,8 @@
 
 // RUN: %clang_cl -### -- %s 2>&1 | FileCheck -check-prefix=CHECK-MT %s
 // RUN: %clang_cl -### /MT -- %s 2>&1 | FileCheck -check-prefix=CHECK-MT %s
+// RUN: %clang -### --target=x86_64-windows-msvc -fms-runtime-lib=static -- %s \
+// RUN:   2>&1 | FileCheck -check-prefix=CHECK-MT %s
 // CHECK-MT-NOT: "-D_DEBUG"
 // CHECK-MT: "-D_MT"
 // CHECK-MT-NOT: "-D_DLL"
@@ -19,6 +21,8 @@
 
 // RUN: %clang_cl -### /MTd -- %s 2>&1 | FileCheck -check-prefix=CHECK-MTd %s
 // RUN: %clang_cl -### /LD /MTd -- %s 2>&1 | FileCheck -check-prefix=CHECK-MTd %s
+// RUN: %clang -### --target=x86_64-windows-msvc -fms-runtime-lib=static_dbg \
+// RUN:   -- %s 2>&1 | FileCheck -check-prefix=CHECK-MTd %s
 // CHECK-MTd: "-D_DEBUG"
 // CHECK-MTd: "-D_MT"
 // CHECK-MTd-NOT: "-D_DLL"
@@ -27,6 +31,8 @@
 // CHECK-MTd: "--dependent-lib=oldnames"
 
 // RUN: %clang_cl -### /MD -- %s 2>&1 | FileCheck -check-prefix=CHECK-MD %s
+// RUN: %clang -### --target=x86_64-windows-msvc -fms-runtime-lib=dll -- %s \
+// RUN:   2>&1 | FileCheck -check-prefix=CHECK-MD %s
 // CHECK-MD-NOT: "-D_DEBUG"
 // CHECK-MD: "-D_MT"
 // CHECK-MD: "-D_DLL"
@@ -34,6 +40,8 @@
 // CHECK-MD: "--dependent-lib=oldnames"
 
 // RUN: %clang_cl -### /MDd -- %s 2>&1 | FileCheck -check-prefix=CHECK-MDd %s
+// RUN: %clang -### --target=x86_64-windows-msvc -fms-runtime-lib=dll_dbg -- \
+// RUN:   %s 2>&1 | FileCheck -check-prefix=CHECK-MDd %s
 // CHECK-MDd: "-D_DEBUG"
 // CHECK-MDd: "-D_MT"
 // CHECK-MDd: "-D_DLL"