Merging r143752:

------------------------------------------------------------------------
r143752 | chandlerc | 2011-11-04 16:49:05 -0700 (Fri, 04 Nov 2011) | 5 lines

Begin the migration of header search logic to the driver, starting with
Windows. There are still FIXMEs and lots of problems with this code.
Some of them will be addressed shortly by my follow-up patches, but most
are going to wait until we isolate this code and can fix it properly.
This version should be no worse than what we had before.
------------------------------------------------------------------------


git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_30@143930 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 291 insertions, 244 deletions

diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index da76edb191..73b67d82bc 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -40,6 +40,13 @@
 
 #include "llvm/Config/config.h" // for CXX_INCLUDE_ROOT
 
+// Include the necessary headers to interface with the Windows registry and
+// environment.
+#ifdef _MSC_VER
+  #define WIN32_LEAN_AND_MEAN 1
+  #include <windows.h>
+#endif
+
 using namespace clang::driver;
 using namespace clang::driver::toolchains;
 using namespace clang;
@@ -2024,3 +2031,265 @@ const char *Windows::GetForcedPicModel() const {
     return "pic";
   return 0;
 }
+
+// FIXME: This probably should goto to some platform utils place.
+#ifdef _MSC_VER
+
+/// \brief Read registry string.
+/// This also supports a means to look for high-versioned keys by use
+/// of a $VERSION placeholder in the key path.
+/// $VERSION in the key path is a placeholder for the version number,
+/// causing the highest value path to be searched for and used.
+/// I.e. "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\VisualStudio\\$VERSION".
+/// There can be additional characters in the component.  Only the numberic
+/// characters are compared.
+static bool getSystemRegistryString(const char *keyPath, const char *valueName,
+                                    char *value, size_t maxLength) {
+  HKEY hRootKey = NULL;
+  HKEY hKey = NULL;
+  const char* subKey = NULL;
+  DWORD valueType;
+  DWORD valueSize = maxLength - 1;
+  long lResult;
+  bool returnValue = false;
+
+  if (strncmp(keyPath, "HKEY_CLASSES_ROOT\\", 18) == 0) {
+    hRootKey = HKEY_CLASSES_ROOT;
+    subKey = keyPath + 18;
+  } else if (strncmp(keyPath, "HKEY_USERS\\", 11) == 0) {
+    hRootKey = HKEY_USERS;
+    subKey = keyPath + 11;
+  } else if (strncmp(keyPath, "HKEY_LOCAL_MACHINE\\", 19) == 0) {
+    hRootKey = HKEY_LOCAL_MACHINE;
+    subKey = keyPath + 19;
+  } else if (strncmp(keyPath, "HKEY_CURRENT_USER\\", 18) == 0) {
+    hRootKey = HKEY_CURRENT_USER;
+    subKey = keyPath + 18;
+  } else {
+    return false;
+  }
+
+  const char *placeHolder = strstr(subKey, "$VERSION");
+  char bestName[256];
+  bestName[0] = '\0';
+  // If we have a $VERSION placeholder, do the highest-version search.
+  if (placeHolder) {
+    const char *keyEnd = placeHolder - 1;
+    const char *nextKey = placeHolder;
+    // Find end of previous key.
+    while ((keyEnd > subKey) && (*keyEnd != '\\'))
+      keyEnd--;
+    // Find end of key containing $VERSION.
+    while (*nextKey && (*nextKey != '\\'))
+      nextKey++;
+    size_t partialKeyLength = keyEnd - subKey;
+    char partialKey[256];
+    if (partialKeyLength > sizeof(partialKey))
+      partialKeyLength = sizeof(partialKey);
+    strncpy(partialKey, subKey, partialKeyLength);
+    partialKey[partialKeyLength] = '\0';
+    HKEY hTopKey = NULL;
+    lResult = RegOpenKeyEx(hRootKey, partialKey, 0, KEY_READ, &hTopKey);
+    if (lResult == ERROR_SUCCESS) {
+      char keyName[256];
+      int bestIndex = -1;
+      double bestValue = 0.0;
+      DWORD index, size = sizeof(keyName) - 1;
+      for (index = 0; RegEnumKeyEx(hTopKey, index, keyName, &size, NULL,
+          NULL, NULL, NULL) == ERROR_SUCCESS; index++) {
+        const char *sp = keyName;
+        while (*sp && !isdigit(*sp))
+          sp++;
+        if (!*sp)
+          continue;
+        const char *ep = sp + 1;
+        while (*ep && (isdigit(*ep) || (*ep == '.')))
+          ep++;
+        char numBuf[32];
+        strncpy(numBuf, sp, sizeof(numBuf) - 1);
+        numBuf[sizeof(numBuf) - 1] = '\0';
+        double value = strtod(numBuf, NULL);
+        if (value > bestValue) {
+          bestIndex = (int)index;
+          bestValue = value;
+          strcpy(bestName, keyName);
+        }
+        size = sizeof(keyName) - 1;
+      }
+      // If we found the highest versioned key, open the key and get the value.
+      if (bestIndex != -1) {
+        // Append rest of key.
+        strncat(bestName, nextKey, sizeof(bestName) - 1);
+        bestName[sizeof(bestName) - 1] = '\0';
+        // Open the chosen key path remainder.
+        lResult = RegOpenKeyEx(hTopKey, bestName, 0, KEY_READ, &hKey);
+        if (lResult == ERROR_SUCCESS) {
+          lResult = RegQueryValueEx(hKey, valueName, NULL, &valueType,
+            (LPBYTE)value, &valueSize);
+          if (lResult == ERROR_SUCCESS)
+            returnValue = true;
+          RegCloseKey(hKey);
+        }
+      }
+      RegCloseKey(hTopKey);
+    }
+  } else {
+    lResult = RegOpenKeyEx(hRootKey, subKey, 0, KEY_READ, &hKey);
+    if (lResult == ERROR_SUCCESS) {
+      lResult = RegQueryValueEx(hKey, valueName, NULL, &valueType,
+        (LPBYTE)value, &valueSize);
+      if (lResult == ERROR_SUCCESS)
+        returnValue = true;
+      RegCloseKey(hKey);
+    }
+  }
+  return returnValue;
+}
+
+/// \brief Get Windows SDK installation directory.
+static bool getWindowsSDKDir(std::string &path) {
+  char windowsSDKInstallDir[256];
+  // Try the Windows registry.
+  bool hasSDKDir = getSystemRegistryString(
+   "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Microsoft SDKs\\Windows\\$VERSION",
+                                           "InstallationFolder",
+                                           windowsSDKInstallDir,
+                                           sizeof(windowsSDKInstallDir) - 1);
+    // If we have both vc80 and vc90, pick version we were compiled with.
+  if (hasSDKDir && windowsSDKInstallDir[0]) {
+    path = windowsSDKInstallDir;
+    return true;
+  }
+  return false;
+}
+
+  // Get Visual Studio installation directory.
+static bool getVisualStudioDir(std::string &path) {
+  // First check the environment variables that vsvars32.bat sets.
+  const char* vcinstalldir = getenv("VCINSTALLDIR");
+  if (vcinstalldir) {
+    char *p = const_cast<char *>(strstr(vcinstalldir, "\\VC"));
+    if (p)
+      *p = '\0';
+    path = vcinstalldir;
+    return true;
+  }
+
+  char vsIDEInstallDir[256];
+  char vsExpressIDEInstallDir[256];
+  // Then try the windows registry.
+  bool hasVCDir = getSystemRegistryString(
+    "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\VisualStudio\\$VERSION",
+    "InstallDir", vsIDEInstallDir, sizeof(vsIDEInstallDir) - 1);
+  bool hasVCExpressDir = getSystemRegistryString(
+    "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\VCExpress\\$VERSION",
+    "InstallDir", vsExpressIDEInstallDir, sizeof(vsExpressIDEInstallDir) - 1);
+    // If we have both vc80 and vc90, pick version we were compiled with.
+  if (hasVCDir && vsIDEInstallDir[0]) {
+    char *p = (char*)strstr(vsIDEInstallDir, "\\Common7\\IDE");
+    if (p)
+      *p = '\0';
+    path = vsIDEInstallDir;
+    return true;
+  }
+  
+  if (hasVCExpressDir && vsExpressIDEInstallDir[0]) {
+    char *p = (char*)strstr(vsExpressIDEInstallDir, "\\Common7\\IDE");
+    if (p)
+      *p = '\0';
+    path = vsExpressIDEInstallDir;
+    return true;
+  }
+
+  // Try the environment.
+  const char *vs100comntools = getenv("VS100COMNTOOLS");
+  const char *vs90comntools = getenv("VS90COMNTOOLS");
+  const char *vs80comntools = getenv("VS80COMNTOOLS");
+  const char *vscomntools = NULL;
+
+  // Try to find the version that we were compiled with
+  if(false) {}
+  #if (_MSC_VER >= 1600)  // VC100
+  else if(vs100comntools) {
+    vscomntools = vs100comntools;
+  }
+  #elif (_MSC_VER == 1500) // VC80
+  else if(vs90comntools) {
+    vscomntools = vs90comntools;
+  }
+  #elif (_MSC_VER == 1400) // VC80
+  else if(vs80comntools) {
+    vscomntools = vs80comntools;
+  }
+  #endif
+  // Otherwise find any version we can
+  else if (vs100comntools)
+    vscomntools = vs100comntools;
+  else if (vs90comntools)
+    vscomntools = vs90comntools;
+  else if (vs80comntools)
+    vscomntools = vs80comntools;
+
+  if (vscomntools && *vscomntools) {
+    const char *p = strstr(vscomntools, "\\Common7\\Tools");
+    path = p ? std::string(vscomntools, p) : vscomntools;
+    return true;
+  }
+  return false;
+}
+
+// FIXME: Hoist this up, generalize, and document it as more stuff begins using
+// it.
+static void addSystemInclude(const ArgList &DriverArgs, ArgStringList &CC1Args,
+                             const Twine &Path) {
+  CC1Args.push_back("-isystem");
+  CC1Args.push_back(DriverArgs.MakeArgString(Path));
+}
+
+#endif // _MSC_VER
+
+// FIXME: Generalize this and document it as more clients begin to use it.
+static void addSystemIncludes(const ArgList &DriverArgs,
+                              ArgStringList &CC1Args,
+                              ArrayRef<StringRef> Paths) {
+  for (ArrayRef<StringRef>::iterator I = Paths.begin(), E = Paths.end();
+       I != E; ++I) {
+    CC1Args.push_back("-isystem");
+    CC1Args.push_back(DriverArgs.MakeArgString(*I));
+  }
+}
+
+void Windows::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
+                                        ArgStringList &CC1Args) const {
+  std::string VSDir;
+  std::string WindowsSDKDir;
+
+#ifdef _MSC_VER
+  // When built with access to the proper Windows APIs, try to actually find
+  // the correct include paths first.
+  if (getVisualStudioDir(VSDir)) {
+    addSystemInclude(DriverArgs, CC1Args, VSDir + "\\VC\\include");
+    if (getWindowsSDKDir(WindowsSDKDir))
+      addSystemInclude(DriverArgs, CC1Args, WindowsSDKDir + "\\include");
+    else
+      addSystemInclude(DriverArgs, CC1Args,
+                       VSDir + "\\VC\\PlatformSDK\\Include");
+    return;
+  }
+#endif // _MSC_VER
+
+  // As a fallback, select default install paths.
+  const StringRef Paths[] = {
+    "C:/Program Files/Microsoft Visual Studio 10.0/VC/include",
+    "C:/Program Files/Microsoft Visual Studio 9.0/VC/include",
+    "C:/Program Files/Microsoft Visual Studio 9.0/VC/PlatformSDK/Include",
+    "C:/Program Files/Microsoft Visual Studio 8/VC/include",
+    "C:/Program Files/Microsoft Visual Studio 8/VC/PlatformSDK/Include"
+  };
+  addSystemIncludes(DriverArgs, CC1Args, Paths);
+}
+
+void Windows::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                           ArgStringList &CC1Args) const {
+  // FIXME: There should probably be logic here to find libc++ on Windows.
+}
diff --git a/lib/Driver/ToolChains.h b/lib/Driver/ToolChains.h
index dfcb253acd..f0c348402c 100644
--- a/lib/Driver/ToolChains.h
+++ b/lib/Driver/ToolChains.h
@@ -417,6 +417,12 @@ public:
   virtual bool IsUnwindTablesDefault() const;
   virtual const char *GetDefaultRelocationModel() const;
   virtual const char *GetForcedPicModel() const;
+
+  virtual void AddClangSystemIncludeArgs(const ArgList &DriverArgs,
+                                         ArgStringList &CC1Args) const;
+  virtual void AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                            ArgStringList &CC1Args) const;
+
 };
 
 } // end namespace toolchains
diff --git a/lib/Frontend/InitHeaderSearch.cpp b/lib/Frontend/InitHeaderSearch.cpp
index 571f0b27fc..5083c5edf0 100644
--- a/lib/Frontend/InitHeaderSearch.cpp
+++ b/lib/Frontend/InitHeaderSearch.cpp
@@ -27,12 +27,9 @@
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Config/config.h"
-#ifdef _MSC_VER
-  #define WIN32_LEAN_AND_MEAN 1
-  #include <windows.h>
-#endif
 using namespace clang;
 using namespace clang::frontend;
 
@@ -207,219 +204,6 @@ void InitHeaderSearch::AddMinGW64CXXPaths(StringRef Base,
           CXXSystem, true, false, false);
 }
 
-  // FIXME: This probably should goto to some platform utils place.
-#ifdef _MSC_VER
-
-  // Read registry string.
-  // This also supports a means to look for high-versioned keys by use
-  // of a $VERSION placeholder in the key path.
-  // $VERSION in the key path is a placeholder for the version number,
-  // causing the highest value path to be searched for and used.
-  // I.e. "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\VisualStudio\\$VERSION".
-  // There can be additional characters in the component.  Only the numberic
-  // characters are compared.
-static bool getSystemRegistryString(const char *keyPath, const char *valueName,
-                                    char *value, size_t maxLength) {
-  HKEY hRootKey = NULL;
-  HKEY hKey = NULL;
-  const char* subKey = NULL;
-  DWORD valueType;
-  DWORD valueSize = maxLength - 1;
-  long lResult;
-  bool returnValue = false;
-  
-  if (strncmp(keyPath, "HKEY_CLASSES_ROOT\\", 18) == 0) {
-    hRootKey = HKEY_CLASSES_ROOT;
-    subKey = keyPath + 18;
-  } else if (strncmp(keyPath, "HKEY_USERS\\", 11) == 0) {
-    hRootKey = HKEY_USERS;
-    subKey = keyPath + 11;
-  } else if (strncmp(keyPath, "HKEY_LOCAL_MACHINE\\", 19) == 0) {
-    hRootKey = HKEY_LOCAL_MACHINE;
-    subKey = keyPath + 19;
-  } else if (strncmp(keyPath, "HKEY_CURRENT_USER\\", 18) == 0) {
-    hRootKey = HKEY_CURRENT_USER;
-    subKey = keyPath + 18;
-  }
-  else
-    return false;
-  
-  const char *placeHolder = strstr(subKey, "$VERSION");
-  char bestName[256];
-  bestName[0] = '\0';
-  // If we have a $VERSION placeholder, do the highest-version search.
-  if (placeHolder) {
-    const char *keyEnd = placeHolder - 1;
-    const char *nextKey = placeHolder;
-    // Find end of previous key.
-    while ((keyEnd > subKey) && (*keyEnd != '\\'))
-      keyEnd--;
-    // Find end of key containing $VERSION.
-    while (*nextKey && (*nextKey != '\\'))
-      nextKey++;
-    size_t partialKeyLength = keyEnd - subKey;
-    char partialKey[256];
-    if (partialKeyLength > sizeof(partialKey))
-      partialKeyLength = sizeof(partialKey);
-    strncpy(partialKey, subKey, partialKeyLength);
-    partialKey[partialKeyLength] = '\0';
-    HKEY hTopKey = NULL;
-    lResult = RegOpenKeyEx(hRootKey, partialKey, 0, KEY_READ, &hTopKey);
-    if (lResult == ERROR_SUCCESS) {
-      char keyName[256];
-      int bestIndex = -1;
-      double bestValue = 0.0;
-      DWORD index, size = sizeof(keyName) - 1;
-      for (index = 0; RegEnumKeyEx(hTopKey, index, keyName, &size, NULL,
-          NULL, NULL, NULL) == ERROR_SUCCESS; index++) {
-        const char *sp = keyName;
-        while (*sp && !isdigit(*sp))
-          sp++;
-        if (!*sp)
-          continue;
-        const char *ep = sp + 1;
-        while (*ep && (isdigit(*ep) || (*ep == '.')))
-          ep++;
-        char numBuf[32];
-        strncpy(numBuf, sp, sizeof(numBuf) - 1);
-        numBuf[sizeof(numBuf) - 1] = '\0';
-        double value = strtod(numBuf, NULL);
-        if (value > bestValue) {
-          bestIndex = (int)index;
-          bestValue = value;
-          strcpy(bestName, keyName);
-        }
-        size = sizeof(keyName) - 1;
-      }
-      // If we found the highest versioned key, open the key and get the value.
-      if (bestIndex != -1) {
-        // Append rest of key.
-        strncat(bestName, nextKey, sizeof(bestName) - 1);
-        bestName[sizeof(bestName) - 1] = '\0';
-        // Open the chosen key path remainder.
-        lResult = RegOpenKeyEx(hTopKey, bestName, 0, KEY_READ, &hKey);
-        if (lResult == ERROR_SUCCESS) {
-          lResult = RegQueryValueEx(hKey, valueName, NULL, &valueType,
-            (LPBYTE)value, &valueSize);
-          if (lResult == ERROR_SUCCESS)
-            returnValue = true;
-          RegCloseKey(hKey);
-        }
-      }
-      RegCloseKey(hTopKey);
-    }
-  }
-  else {
-    lResult = RegOpenKeyEx(hRootKey, subKey, 0, KEY_READ, &hKey);
-    if (lResult == ERROR_SUCCESS) {
-      lResult = RegQueryValueEx(hKey, valueName, NULL, &valueType,
-        (LPBYTE)value, &valueSize);
-      if (lResult == ERROR_SUCCESS)
-        returnValue = true;
-      RegCloseKey(hKey);
-    }
-  }
-  return returnValue;
-}
-#else // _MSC_VER
-  // Read registry string.
-static bool getSystemRegistryString(const char*, const char*, char*, size_t) {
-  return(false);
-}
-#endif // _MSC_VER
-
-  // Get Visual Studio installation directory.
-static bool getVisualStudioDir(std::string &path) {
-  // First check the environment variables that vsvars32.bat sets.
-  const char* vcinstalldir = getenv("VCINSTALLDIR");
-  if (vcinstalldir) {
-    char *p = const_cast<char *>(strstr(vcinstalldir, "\\VC"));
-    if (p)
-      *p = '\0';
-    path = vcinstalldir;
-    return true;
-  }
-
-  char vsIDEInstallDir[256];
-  char vsExpressIDEInstallDir[256];
-  // Then try the windows registry.
-  bool hasVCDir = getSystemRegistryString(
-    "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\VisualStudio\\$VERSION",
-    "InstallDir", vsIDEInstallDir, sizeof(vsIDEInstallDir) - 1);
-  bool hasVCExpressDir = getSystemRegistryString(
-    "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\VCExpress\\$VERSION",
-    "InstallDir", vsExpressIDEInstallDir, sizeof(vsExpressIDEInstallDir) - 1);
-    // If we have both vc80 and vc90, pick version we were compiled with.
-  if (hasVCDir && vsIDEInstallDir[0]) {
-    char *p = (char*)strstr(vsIDEInstallDir, "\\Common7\\IDE");
-    if (p)
-      *p = '\0';
-    path = vsIDEInstallDir;
-    return true;
-  }
-  
-  if (hasVCExpressDir && vsExpressIDEInstallDir[0]) {
-    char *p = (char*)strstr(vsExpressIDEInstallDir, "\\Common7\\IDE");
-    if (p)
-      *p = '\0';
-    path = vsExpressIDEInstallDir;
-    return true;
-  }
-
-  // Try the environment.
-  const char *vs100comntools = getenv("VS100COMNTOOLS");
-  const char *vs90comntools = getenv("VS90COMNTOOLS");
-  const char *vs80comntools = getenv("VS80COMNTOOLS");
-  const char *vscomntools = NULL;
-
-  // Try to find the version that we were compiled with
-  if(false) {}
-  #if (_MSC_VER >= 1600)  // VC100
-  else if(vs100comntools) {
-    vscomntools = vs100comntools;
-  }
-  #elif (_MSC_VER == 1500) // VC80
-  else if(vs90comntools) {
-    vscomntools = vs90comntools;
-  }
-  #elif (_MSC_VER == 1400) // VC80
-  else if(vs80comntools) {
-    vscomntools = vs80comntools;
-  }
-  #endif
-  // Otherwise find any version we can
-  else if (vs100comntools)
-    vscomntools = vs100comntools;
-  else if (vs90comntools)
-    vscomntools = vs90comntools;
-  else if (vs80comntools)
-    vscomntools = vs80comntools;
-
-  if (vscomntools && *vscomntools) {
-    const char *p = strstr(vscomntools, "\\Common7\\Tools");
-    path = p ? std::string(vscomntools, p) : vscomntools;
-    return true;
-  }
-  return false;
-}
-
-  // Get Windows SDK installation directory.
-static bool getWindowsSDKDir(std::string &path) {
-  char windowsSDKInstallDir[256];
-  // Try the Windows registry.
-  bool hasSDKDir = getSystemRegistryString(
-   "HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Microsoft SDKs\\Windows\\$VERSION",
-                                           "InstallationFolder",
-                                           windowsSDKInstallDir,
-                                           sizeof(windowsSDKInstallDir) - 1);
-    // If we have both vc80 and vc90, pick version we were compiled with.
-  if (hasSDKDir && windowsSDKInstallDir[0]) {
-    path = windowsSDKInstallDir;
-    return(true);
-  }
-  return(false);
-}
-
 void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
                                             const HeaderSearchOptions &HSOpts) {
   llvm::Triple::OSType os = triple.getOS();
@@ -464,33 +248,9 @@ void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
   }
 
   switch (os) {
-  case llvm::Triple::Win32: {
-    std::string VSDir;
-    std::string WindowsSDKDir;
-    if (getVisualStudioDir(VSDir)) {
-      AddPath(VSDir + "\\VC\\include", System, false, false, false);
-      if (getWindowsSDKDir(WindowsSDKDir))
-        AddPath(WindowsSDKDir + "\\include", System, false, false, false);
-      else
-        AddPath(VSDir + "\\VC\\PlatformSDK\\Include",
-                System, false, false, false);
-    } else {
-      // Default install paths.
-      AddPath("C:/Program Files/Microsoft Visual Studio 10.0/VC/include",
-              System, false, false, false);
-      AddPath("C:/Program Files/Microsoft Visual Studio 9.0/VC/include",
-              System, false, false, false);
-      AddPath(
-        "C:/Program Files/Microsoft Visual Studio 9.0/VC/PlatformSDK/Include",
-        System, false, false, false);
-      AddPath("C:/Program Files/Microsoft Visual Studio 8/VC/include",
-              System, false, false, false);
-      AddPath(
-        "C:/Program Files/Microsoft Visual Studio 8/VC/PlatformSDK/Include",
-        System, false, false, false);
-    }
-    break;
-  }
+  case llvm::Triple::Win32:
+    llvm_unreachable("Windows include management is handled in the driver.");
+
   case llvm::Triple::Haiku:
     AddPath("/boot/common/include", System, true, false, false);
     AddPath("/boot/develop/headers/os", System, true, false, false);
@@ -943,6 +703,18 @@ AddDefaultCPlusPlusIncludePaths(const llvm::Triple &triple, const HeaderSearchOp
 void InitHeaderSearch::AddDefaultIncludePaths(const LangOptions &Lang,
                                               const llvm::Triple &triple,
                                             const HeaderSearchOptions &HSOpts) {
+  // NB: This code path is going away. All of the logic is moving into the
+  // driver which has the information necessary to do target-specific
+  // selections of default include paths. Each target which moves there will be
+  // exempted from this logic here until we can delete the entire pile of code.
+  switch (triple.getOS()) {
+  default:
+    break; // Everything else continues to use this routine's logic.
+
+  case llvm::Triple::Win32:
+    return;
+  }
+
   if (Lang.CPlusPlus && HSOpts.UseStandardCXXIncludes &&
       HSOpts.UseStandardSystemIncludes) {
     if (HSOpts.UseLibcxx) {