[PATCH] D85998: Add clang-cl "vctoolsdir" option to specify the location of the msvc toolchain

[Zachary Henkel via Phabricator via cfe-commits]

zahen created this revision.
zahen added reviewers: rnk, hans, thakis.
Herald added subscribers: cfe-commits, dang.
Herald added a project: clang.
zahen requested review of this revision.

Add an option to directly specify where the msvc toolchain lives for clang-cl and avoid unwanted file and registry probes.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D85998

Files:
  clang/include/clang/Driver/Options.td
  clang/lib/Driver/ToolChains/MSVC.cpp
  clang/test/Driver/cl-options.c


Index: clang/test/Driver/cl-options.c
===================================================================
--- clang/test/Driver/cl-options.c
+++ clang/test/Driver/cl-options.c
@@ -682,4 +682,7 @@
 // CLANG-NOT: "--dependent-lib=libcmt"
 // CLANG-NOT: "-vectorize-slp"
 
+// vctoolsdir is handled by the driver; just check that we don't error. Pass -c because fakedir isn't a real toolchain path
+// RUN: %clang_cl -c -vctoolsdir fakedir -- %s 2>&1
+
 void f() { }
Index: clang/lib/Driver/ToolChains/MSVC.cpp
===================================================================
--- clang/lib/Driver/ToolChains/MSVC.cpp
+++ clang/lib/Driver/ToolChains/MSVC.cpp
@@ -66,6 +66,18 @@
 static bool getSystemRegistryString(const char *keyPath, const char *valueName,
                                     std::string &value, std::string *phValue);
 
+// Check command line arguments to try and find a toolchain.
+static bool findVCToolChainViaCommandLine(const ArgList &Args, std::string &Path,
+                                          MSVCToolChain::ToolsetLayout &VSLayout) {
+  // Trust the value supplied by the user.
+   if (Arg *A = Args.getLastArg(options::OPT__SLASH_vctoolsdir)) {
+    Path = A->getValue();
+    VSLayout = MSVCToolChain::ToolsetLayout::VS2017OrNewer;
+    return true;
+  }
+  return false;
+}
+
 // Check various environment variables to try and find a toolchain.
 static bool findVCToolChainViaEnvironment(std::string &Path,
                                           MSVCToolChain::ToolsetLayout &VSLayout) {
@@ -751,7 +763,8 @@
   // what they want to use.
   // Failing that, just try to find the newest Visual Studio version we can
   // and use its default VC toolchain.
-  findVCToolChainViaEnvironment(VCToolChainPath, VSLayout) ||
+    findVCToolChainViaCommandLine(Args, VCToolChainPath, VSLayout) ||
+      findVCToolChainViaEnvironment(VCToolChainPath, VSLayout) ||
       findVCToolChainViaSetupConfig(VCToolChainPath, VSLayout) ||
       findVCToolChainViaRegistry(VCToolChainPath, VSLayout);
 }
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -4737,6 +4737,8 @@
 def _SLASH_Tp : CLCompileJoinedOrSeparate<"Tp">,
   HelpText<"Treat <file> as C++ source file">, MetaVarName<"<file>">;
 def _SLASH_TP : CLCompileFlag<"TP">, HelpText<"Treat all source files as C++">;
+def _SLASH_vctoolsdir : CLJoinedOrSeparate<"vctoolsdir">,
+  HelpText<"Path to the VCToolChain">, MetaVarName<"<dir>">;
 def _SLASH_volatile_iso : Option<["/", "-"], "volatile:iso", KIND_FLAG>,
   Group<_SLASH_volatile_Group>, Flags<[CLOption, DriverOption]>,
   HelpText<"Volatile loads and stores have standard semantics">;


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