From a594fd28e373cb7cd348cf01f6a90e055bf6cf6d Mon Sep 17 00:00:00 2001
From: Petr Hosek <phosek@google.com>
Date: Tue, 22 Sep 2020 01:01:16 -0700
Subject: [PATCH] [Driver] Move detectLibcxxIncludePath to ToolChain

This helper method is useful even outside of Gnu toolchains, so move
it to ToolChain so it can be reused in other toolchains such as Fuchsia.

Differential Revision: https://reviews.llvm.org/D88452
---
 clang/include/clang/Driver/ToolChain.h  |  3 +++
 clang/lib/Driver/ToolChain.cpp          | 23 +++++++++++++++++++++++
 clang/lib/Driver/ToolChains/Fuchsia.cpp |  4 ++--
 clang/lib/Driver/ToolChains/Gnu.cpp     | 22 +---------------------
 4 files changed, 29 insertions(+), 23 deletions(-)

diff --git a/clang/include/clang/Driver/ToolChain.h b/clang/include/clang/Driver/ToolChain.h
index 7495e08..db4c4a7 100644
--- a/clang/include/clang/Driver/ToolChain.h
+++ b/clang/include/clang/Driver/ToolChain.h
@@ -575,6 +575,9 @@ public:
   // given compilation arguments.
   virtual UnwindLibType GetUnwindLibType(const llvm::opt::ArgList &Args) const;
 
+  // Detect the highest available version of libc++ in base path.
+  virtual std::string detectLibcxxIncludePath(StringRef Base) const;
+
   /// AddClangCXXStdlibIncludeArgs - Add the clang -cc1 level arguments to set
   /// the include paths to use for the given C++ standard library type.
   virtual void
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 8991216..8e98e32 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -924,6 +924,29 @@ void ToolChain::addExternCSystemIncludeIfExists(const ArgList &DriverArgs,
   }
 }
 
+std::string ToolChain::detectLibcxxIncludePath(StringRef Base) const {
+  std::error_code EC;
+  int MaxVersion = 0;
+  std::string MaxVersionString;
+  for (llvm::vfs::directory_iterator LI = getVFS().dir_begin(Base, EC), LE;
+       !EC && LI != LE; LI = LI.increment(EC)) {
+    StringRef VersionText = llvm::sys::path::filename(LI->path());
+    int Version;
+    if (VersionText[0] == 'v' &&
+        !VersionText.slice(1, StringRef::npos).getAsInteger(10, Version)) {
+      if (Version > MaxVersion) {
+        MaxVersion = Version;
+        MaxVersionString = std::string(VersionText);
+      }
+    }
+  }
+  if (!MaxVersion)
+    return "";
+  SmallString<128> P(Base);
+  llvm::sys::path::append(P, MaxVersionString);
+  return std::string(P.str());
+}
+
 void ToolChain::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
                                              ArgStringList &CC1Args) const {
   // Header search paths should be handled by each of the subclasses.
diff --git a/clang/lib/Driver/ToolChains/Fuchsia.cpp b/clang/lib/Driver/ToolChains/Fuchsia.cpp
index 781179b..e5f23ee 100644
--- a/clang/lib/Driver/ToolChains/Fuchsia.cpp
+++ b/clang/lib/Driver/ToolChains/Fuchsia.cpp
@@ -319,8 +319,8 @@ void Fuchsia::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
   switch (GetCXXStdlibType(DriverArgs)) {
   case ToolChain::CST_Libcxx: {
     SmallString<128> P(getDriver().Dir);
-    llvm::sys::path::append(P, "..", "include", "c++", "v1");
-    addSystemInclude(DriverArgs, CC1Args, P.str());
+    llvm::sys::path::append(P, "..", "include", "c++");
+    addSystemInclude(DriverArgs, CC1Args, detectLibcxxIncludePath(P.str()));
     break;
   }
 
diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
index f384368..3778b6f 100644
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -2877,31 +2877,11 @@ void Generic_GCC::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
   }
 }
 
-static std::string DetectLibcxxIncludePath(llvm::vfs::FileSystem &vfs,
-                                           StringRef base) {
-  std::error_code EC;
-  int MaxVersion = 0;
-  std::string MaxVersionString;
-  for (llvm::vfs::directory_iterator LI = vfs.dir_begin(base, EC), LE;
-       !EC && LI != LE; LI = LI.increment(EC)) {
-    StringRef VersionText = llvm::sys::path::filename(LI->path());
-    int Version;
-    if (VersionText[0] == 'v' &&
-        !VersionText.slice(1, StringRef::npos).getAsInteger(10, Version)) {
-      if (Version > MaxVersion) {
-        MaxVersion = Version;
-        MaxVersionString = std::string(VersionText);
-      }
-    }
-  }
-  return MaxVersion ? (base + "/" + MaxVersionString).str() : "";
-}
-
 void
 Generic_GCC::addLibCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
                                    llvm::opt::ArgStringList &CC1Args) const {
   auto AddIncludePath = [&](std::string Path) {
-    std::string IncludePath = DetectLibcxxIncludePath(getVFS(), Path);
+    std::string IncludePath = detectLibcxxIncludePath(Path);
     if (IncludePath.empty() || !getVFS().exists(IncludePath))
       return false;
     addSystemInclude(DriverArgs, CC1Args, IncludePath);
-- 
1.8.3.1