commit 58df1affedc0d68eda16b87984a31dea217ff930
author Mike Rice <michael.p.rice@intel.com> Tue Sep 11 17:10:44 2018 +0000
committer Mike Rice <michael.p.rice@intel.com> Tue Sep 11 17:10:44 2018 +0000
tree 055ccfe2a9023cdc9d883947849814a3d50e3a2d
parent 12fd6bd4ad8f472304dc51120c11125f5627160b

[clang-cl, PCH] Support for /Yc and /Yu without filename and #pragma hdrstop

With clang-cl, when the user specifies /Yc or /Yu without a filename
the compiler uses a #pragma hdrstop in the main source file to
determine the end of the PCH. If a header is specified with /Yc or
/Yu #pragma hdrstop has no effect.

The optional #pragma hdrstop filename argument is not yet supported.

Differential Revision: https://reviews.llvm.org/D51391

llvm-svn: 341963

clang/lib/Driver/Driver.cpp

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 14cfc48..4764d4e 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -2982,22 +2982,9 @@
     }
   }
 
-  // Diagnose unsupported forms of /Yc /Yu. Ignore /Yc/Yu for now if:
-  // * no filename after it
-  // * both /Yc and /Yu passed but with different filenames
-  // * corresponding file not also passed as /FI
+  // Ignore /Yc/Yu if both /Yc and /Yu passed but with different filenames.
   Arg *YcArg = Args.getLastArg(options::OPT__SLASH_Yc);
   Arg *YuArg = Args.getLastArg(options::OPT__SLASH_Yu);
-  if (YcArg && YcArg->getValue()[0] == '\0') {
-    Diag(clang::diag::warn_drv_ycyu_no_arg_clang_cl) << YcArg->getSpelling();
-    Args.eraseArg(options::OPT__SLASH_Yc);
-    YcArg = nullptr;
-  }
-  if (YuArg && YuArg->getValue()[0] == '\0') {
-    Diag(clang::diag::warn_drv_ycyu_no_arg_clang_cl) << YuArg->getSpelling();
-    Args.eraseArg(options::OPT__SLASH_Yu);
-    YuArg = nullptr;
-  }
   if (YcArg && YuArg && strcmp(YcArg->getValue(), YuArg->getValue()) != 0) {
     Diag(clang::diag::warn_drv_ycyu_different_arg_clang_cl);
     Args.eraseArg(options::OPT__SLASH_Yc);
@@ -4279,11 +4266,11 @@
     // extension of .pch is assumed. "
     if (!llvm::sys::path::has_extension(Output))
       Output += ".pch";
-  } else if (Arg *YcArg = C.getArgs().getLastArg(options::OPT__SLASH_Yc)) {
-    Output = YcArg->getValue();
-    llvm::sys::path::replace_extension(Output, ".pch");
   } else {
-    Output = BaseName;
+    if (Arg *YcArg = C.getArgs().getLastArg(options::OPT__SLASH_Yc))
+      Output = YcArg->getValue();
+    if (Output.empty())
+      Output = BaseName;
     llvm::sys::path::replace_extension(Output, ".pch");
   }
   return Output.str();

clang/lib/Driver/ToolChains/Clang.cpp

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 959a9b1..f3f02a0 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -1105,10 +1105,19 @@
       StringRef ThroughHeader = YcArg ? YcArg->getValue() : YuArg->getValue();
       if (!isa<PrecompileJobAction>(JA)) {
         CmdArgs.push_back("-include-pch");
-        CmdArgs.push_back(Args.MakeArgString(D.GetClPchPath(C, ThroughHeader)));
+        CmdArgs.push_back(Args.MakeArgString(D.GetClPchPath(
+            C, !ThroughHeader.empty()
+                   ? ThroughHeader
+                   : llvm::sys::path::filename(Inputs[0].getBaseInput()))));
       }
-      CmdArgs.push_back(
-          Args.MakeArgString(Twine("-pch-through-header=") + ThroughHeader));
+
+      if (ThroughHeader.empty()) {
+        CmdArgs.push_back(Args.MakeArgString(
+            Twine("-pch-through-hdrstop-") + (YcArg ? "create" : "use")));
+      } else {
+        CmdArgs.push_back(
+            Args.MakeArgString(Twine("-pch-through-header=") + ThroughHeader));
+      }
     }
   }