[Driver] Add --vfsoverlay flag

This flag implies `-ivfsoverlay`, and additionally passes the same
argument to the linker if it supports it. At present the only linker
which does is lld-link, so this functionality has only been added to
the MSVC toolchain. Additionally this option has been made a
CoreOption so that clang-cl can use it without `-Xclang`

Differential Revision: https://reviews.llvm.org/D141808

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 96904518a51d705508c3af41bb99e50e7101c5a8..9b7f30454534b9e439ed7e4e7a56bf0cd8a54626 100644 (file)
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3400,6 +3400,9 @@ def iwithsysroot : JoinedOrSeparate<["-"], "iwithsysroot">, Group<clang_i_Group>
   Flags<[CC1Option]>;
 def ivfsoverlay : JoinedOrSeparate<["-"], "ivfsoverlay">, Group<clang_i_Group>, Flags<[CC1Option]>,
   HelpText<"Overlay the virtual filesystem described by file over the real file system">;
+def vfsoverlay : JoinedOrSeparate<["-", "--"], "vfsoverlay">, Flags<[CC1Option, CoreOption]>,
+  HelpText<"Overlay the virtual filesystem described by file over the real file system. "
+           "Additionally, pass this overlay file to the linker if it supports it">;
 def imultilib : Separate<["-"], "imultilib">, Group<gfortran_Group>;
 def keep__private__externs : Flag<["-"], "keep_private_externs">;
 def l : JoinedOrSeparate<["-"], "l">, Flags<[LinkerInput, RenderJoined]>,

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index c97856a47686a27c258b4cc65832aa6081171ca2..7b91fdf93328673dc4ec8030ff7b87d661550436 100644 (file)
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -7038,6 +7038,13 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     A->claim();
   }
 
+  // Forward --vfsoverlay to -cc1.
+  for (const Arg *A : Args.filtered(options::OPT_vfsoverlay)) {
+    CmdArgs.push_back("--vfsoverlay");
+    CmdArgs.push_back(A->getValue());
+    A->claim();
+  }
+
   // Setup statistics file output.
   SmallString<128> StatsFile = getStatsFileName(Args, Output, Input, D);
   if (!StatsFile.empty())

diff --git a/clang/lib/Driver/ToolChains/MSVC.cpp b/clang/lib/Driver/ToolChains/MSVC.cpp
index 223a4e8a1560fe4b077622fd68b0c950d1bf14a5..13a7a2f47cf495167986e841e3a9b02825e92078 100644 (file)
--- a/clang/lib/Driver/ToolChains/MSVC.cpp
+++ b/clang/lib/Driver/ToolChains/MSVC.cpp
@@ -312,6 +312,11 @@ void visualstudio::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   if (Linker.equals_insensitive("lld"))
     Linker = "lld-link";
 
+  if (Linker == "lld-link")
+    for (Arg *A : Args.filtered(options::OPT_vfsoverlay))
+      CmdArgs.push_back(
+          Args.MakeArgString(std::string("/vfsoverlay:") + A->getValue()));
+
   if (Linker.equals_insensitive("link")) {
     // If we're using the MSVC linker, it's not sufficient to just use link
     // from the program PATH, because other environments like GnuWin32 install

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 86717cc6ebfbfa05a05693857d85230f3b6342e5..84b23452660369f59eb8d12a934559fdab6e7feb 100644 (file)
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3167,7 +3167,7 @@ static bool ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args,
     Opts.AddSystemHeaderPrefix(
         A->getValue(), A->getOption().matches(OPT_system_header_prefix));
 
-  for (const auto *A : Args.filtered(OPT_ivfsoverlay))
+  for (const auto *A : Args.filtered(OPT_ivfsoverlay, OPT_vfsoverlay))
     Opts.AddVFSOverlayFile(A->getValue());
 
   return Diags.getNumErrors() == NumErrorsBefore;

diff --git a/clang/test/Driver/msvc-link.c b/clang/test/Driver/msvc-link.c
index 1ee17fc63c321359edade2c847b2c04282bb00d7..52efaf5ece26685f05331864f80471a12e28dd60 100644 (file)
--- a/clang/test/Driver/msvc-link.c
+++ b/clang/test/Driver/msvc-link.c
@@ -30,3 +30,9 @@
 // NOREPRO: "-out:msvc-link.exe"
 // NOREPRO: "-nologo"
 // NOREPRO-NOT: "-Brepro"
+
+// RUN: %clang_cl -fuse-ld=lld --vfsoverlay %s -### -- %s 2>&1 | FileCheck --check-prefix=VFSOVERLAY %s
+// VFSOVERLAY: -cc1"
+// VFSOVERLAY: "--vfsoverlay"
+// VFSOVERLAY: lld-link"
+// VFSOVERLAY: "/vfsoverlay:

diff --git a/clang/test/Driver/vfsoverlay.c b/clang/test/Driver/vfsoverlay.c
index 6ae494544f9fdd6804ff4a608dd7243588af2acf..694cf623c4476d6d4e4541393fdfbf36d4a5cf8a 100644 (file)
--- a/clang/test/Driver/vfsoverlay.c
+++ b/clang/test/Driver/vfsoverlay.c
@@ -1,5 +1,8 @@
 // RUN: %clang -ivfsoverlay foo.h -### %s 2>&1 | FileCheck %s
 // CHECK: "-ivfsoverlay" "foo.h"
 
+// RUN: %clang --vfsoverlay foo.h -### %s 2>&1 | FileCheck %s --check-prefix=CHECK2
+// CHECK2: "--vfsoverlay" "foo.h"
+
 // RUN: not %clang -ivfsoverlay foo.h %s 2>&1 | FileCheck -check-prefix=CHECK-MISSING %s
 // CHECK-MISSING: virtual filesystem overlay file 'foo.h' not found