Index: docs/UsersManual.rst
===================================================================
--- docs/UsersManual.rst
+++ docs/UsersManual.rst
@@ -644,6 +644,54 @@
 option tells Clang to put double-quotes around the entire filename, which
 is the convention used by NMake and Jom.
 
+Configuration files
+-------------------
+
+Configuration files group command line options and allow to specify all of
+them just by referencing the configuration file. They may be used, for
+instance to collect options required to tune compilation for particular
+target, such as -L, -I, -l, --sysroot, codegen options etc.
+
+Command line option `--config` can be used to specify configuration file in
+a clang invocation. For instance:
+
+::
+
+    clang --config /home/user/cfgs/testing.txt
+    clang --config debug.cfg
+
+If the provided argument contains a directory separator, it is considered as
+a file path, options are read from that file. Otherwise the argument is treated
+as a file name and is searched for in the directories: `~/.llvm` and the
+directory where clang executable resides. The first found file is used. It is
+an error if the required file cannot be found.
+
+Another way to specify configuration file is to encode it in executable name. For
+instance, if clang executable is named `armv7l-clang` (it may be a symbolic link
+to `clang`), then clang will search file `armv7l.cfg` in the directory where clang
+resides.
+
+The configuration file consists of command line options specified on one or several
+lines. Lines composed of whitespace characters only are ignored as well as lines in
+which the first non-blank character is `#`. Long options may be split between several
+lines by trailing backslash. Here is an example of config file:
+
+::
+
+    # Several options on line
+    -c --target=x86_64-unknown-linux-gnu
+
+    # Long option split between lines
+    -I/usr/lib/gcc/x86_64-linux-gnu/5.4.0/../../../../\
+    include/c++/5.4.0
+
+    # other config files may be included
+    @linux.options
+
+Files included by directives `@file` in configuration files are resolved relative to
+the including file. For instance if a config file `~/.llvm/target.cfg` contains
+directive `@os/linux.opts`, the file `linux.opts` is searched for in the directory
+`~/.llvm/os`.
 
 Language and Target-Independent Features
 ========================================
Index: include/clang/Driver/Driver.h
===================================================================
--- include/clang/Driver/Driver.h
+++ include/clang/Driver/Driver.h
@@ -207,6 +207,9 @@
   /// Name to use when invoking gcc/g++.
   std::string CCCGenericGCCName;
 
+  /// Name of configuration file if used.
+  std::string ConfigFile;
+
   /// Whether to check that input files exist when constructing compilation
   /// jobs.
   unsigned CheckInputsExist : 1;
@@ -272,6 +275,9 @@
   /// Name to use when invoking gcc/g++.
   const std::string &getCCCGenericGCCName() const { return CCCGenericGCCName; }
 
+  const std::string &getConfigFile() const { return ConfigFile; }
+  void setConfigFile(StringRef x) { ConfigFile = x; }
+
   const llvm::opt::OptTable &getOpts() const { return *Opts; }
 
   const DiagnosticsEngine &getDiags() const { return Diags; }
Index: lib/Driver/Driver.cpp
===================================================================
--- lib/Driver/Driver.cpp
+++ lib/Driver/Driver.cpp
@@ -1086,6 +1086,10 @@
 
   // Print out the install directory.
   OS << "InstalledDir: " << InstalledDir << '\n';
+
+  // If configuration file was used, print its path.
+  if (!ConfigFile.empty())
+    OS << "Configuration file: " << ConfigFile << '\n';
 }
 
 /// PrintDiagnosticCategories - Implement the --print-diagnostic-categories
Index: test/Driver/Inputs/config-1.cfg
===================================================================
--- /dev/null
+++ test/Driver/Inputs/config-1.cfg
@@ -0,0 +1,7 @@
+
+    
+# Empty lines and line started with # are ignored
+-Werror -std=\
+c99
+    # Target
+    -target x86_64-apple-darwin
\ No newline at end of file
Index: test/Driver/Inputs/config-2.cfg
===================================================================
--- /dev/null
+++ test/Driver/Inputs/config-2.cfg
@@ -0,0 +1,6 @@
+# target
+-target x86_64-unknown-linux-gnu
+
+# nested inclusion
+@config-3.cfg
+@config/config-4.cfg
Index: test/Driver/Inputs/config-3.cfg
===================================================================
--- /dev/null
+++ test/Driver/Inputs/config-3.cfg
@@ -0,0 +1 @@
+-Wundefined-func-template
Index: test/Driver/Inputs/config/config-4.cfg
===================================================================
--- /dev/null
+++ test/Driver/Inputs/config/config-4.cfg
@@ -0,0 +1 @@
+-isysroot /opt/data
Index: test/Driver/config-file.c
===================================================================
--- /dev/null
+++ test/Driver/config-file.c
@@ -0,0 +1,34 @@
+//--- Config file (full path) in output of -###
+//
+// RUN: %clang --config %S/Inputs/config-1.cfg -c %s -### 2>&1 | FileCheck %s -check-prefix CHECK-HHH
+// CHECK-HHH: Target: x86_64-apple-darwin
+// CHECK-HHH: Configuration file: {{.*}}/Inputs/config-1.cfg
+// CHECK-HHH: -Werror
+// CHECK-HHH: -std=c99
+
+//--- Nested config files
+//
+// RUN: %clang --config %S/Inputs/config-2.cfg -### 2>&1 | FileCheck %s -check-prefix CHECK-HHH2
+// CHECK-HHH2: Target: x86_64-unknown-linux
+// CHECK-HHH2: Configuration file: {{.*}}/Inputs/config-2.cfg
+// CHECK-HHH2: -Wundefined-func-template
+// CHECK-HHH2: -isysroot /opt/data
+
+//--- Unexistent config file (full path) in output of -###
+//
+// RUN: not %clang --config %S/Inputs/inexistent.cfg -c %s -### 2>&1 | FileCheck %s -check-prefix CHECK-INEX
+// CHECK-INEX: Configuration file {{.*}}/Inputs/inexistent.cfg' specified by option '--config' cannot be found
+
+//--- Unexistent config file (file name) in output of -###
+//
+// RUN: not %clang --config inexistent-config-file-for-tests.cfg -c %s -### 2>&1 | FileCheck %s -check-prefix CHECK-INEX-NOSEARCH
+// CHECK-INEX-NOSEARCH: Configuration {{.*}}inexistent-config-file-for-tests.cfg' specified by option '--config' cannot be found in directories:
+// CHECK-INEX-NOSEARCH: ~/.llvm
+// RUN: not %clang --config inexistent-config-file-for-tests.cfg -c %s -### 2>&1 | grep '%bindir'
+
+//--- Config file (full path) in output of -v
+//
+// RUN: %clang --config %S/Inputs/config-1.cfg -c %s -v 2>&1 | FileCheck %s -check-prefix CHECK-V
+// CHECK-V: Target: x86_64-apple-darwin
+// CHECK-V: Configuration file: {{.*}}/Inputs/config-1.cfg
+// CHECK-V: -triple{{.*}}x86_64-apple-
Index: test/Driver/config-file2.c
===================================================================
--- /dev/null
+++ test/Driver/config-file2.c
@@ -0,0 +1,29 @@
+// REQUIRES: shell
+
+//--- Invocation qqq-clang tries to find config file qqq.cfg
+//
+// RUN: mkdir -p %T/testbin
+// RUN: [ ! -s %T/testbin/qqq-clang ] || rm %T/testbin/qqq-clang
+// RUN: ln -s %clang %T/testbin/qqq-clang
+// RUN: echo "-Wundefined-func-template" > %T/testbin/qqq.cfg
+// RUN: %T/testbin/qqq-clang -c %s -### 2>&1 | FileCheck %s
+// CHECK: Configuration file: {{.*}}/testbin/qqq.cfg
+// CHECK: -Wundefined-func-template
+
+//--- Config files are searched for in binary directory as well.
+//
+// RUN: [ ! -s %T/testbin/clang ] || rm %T/testbin/clang
+// RUN: ln -s %clang %T/testbin/clang
+// RUN: echo "-Werror" > %T/testbin/aaa.cfg
+// RUN: %T/testbin/clang --config aaa.cfg -c %s -### 2>&1 | FileCheck %s -check-prefix CHECK-BIN
+// CHECK-BIN: Configuration file: {{.*}}/testbin/aaa.cfg
+// CHECK-BIN: -Werror
+
+// RUN: mkdir -p %T/workdir
+// RUN: echo "@subdir/cfg-s2" > %T/workdir/cfg-1
+// RUN: mkdir -p %T/workdir/subdir
+// RUN: echo "-Wundefined-var-template" > %T/workdir/subdir/cfg-s2
+// RUN: ( cd %T && %clang --config workdir/cfg-1 -c %s -### 2>&1 | FileCheck %s -check-prefix CHECK-REL )
+// CHECK-REL: Configuration file: {{.*}}/workdir/cfg-1
+// CHECK-REL: -Wundefined-var-template
+
Index: test/Driver/lit.local.cfg
===================================================================
--- test/Driver/lit.local.cfg
+++ test/Driver/lit.local.cfg
@@ -4,6 +4,8 @@
 config.substitutions.insert(0,
     ('%clang_cc1',
      """*** Do not use 'clang -cc1' in Driver tests. ***""") )
+config.substitutions.append( ('%bindir',
+                              os.path.dirname(config.clang)) )
 
 # Remove harmful environmental variables for clang Driver tests.
 # Some might be useful for other tests so they are only removed here.
Index: tools/driver/driver.cpp
===================================================================
--- tools/driver/driver.cpp
+++ tools/driver/driver.cpp
@@ -305,6 +305,35 @@
   return 1;
 }
 
+// Directories searched for configuration specified by option '--config'.
+static const char * const SearchDirs[] = { "~/.llvm" };
+
+/// Deduce configuration name if it is encoded in the executable name.
+///
+/// \param ConfigFile [out] Is assigned configuration file path.
+/// \param ProgramName [in] clang executable path.
+/// \return True if configuration file was found.
+///
+/// If clang executable is named e.g. 'armv7l-clang' the function tries to
+/// find config file 'armv7l.cfg'. If it is found, its path is put into
+/// ConfigFile and the function returns true.
+///
+static bool findConfigFileFromProgramName(
+    llvm::SmallVectorImpl<char> &ConfigFile, StringRef ProgramName) {
+  ConfigFile.clear();
+  StringRef PName = llvm::sys::path::stem(ProgramName);
+  size_t Pos = PName.find("-clang");
+  if (Pos != StringRef::npos) {
+    ConfigFile.append(PName.begin(), PName.begin() + Pos);
+    const StringRef Ext(".cfg");
+    ConfigFile.append(Ext.begin(), Ext.end());
+    std::string CName(ConfigFile.begin(), ConfigFile.size());
+    return llvm::cl::searchForFile(ConfigFile, ArrayRef<const char *>(),
+                                   ProgramName, CName);
+  }
+  return false;
+}
+
 int main(int argc_, const char **argv_) {
   llvm::sys::PrintStackTraceOnErrorSignal(argv_[0]);
   llvm::PrettyStackTraceProgram X(argc_, argv_);
@@ -330,6 +359,31 @@
   llvm::BumpPtrAllocator A;
   llvm::StringSaver Saver(A);
 
+  // Try reading options from configuration file.
+  llvm::SmallString<128> ConfigFile;
+  llvm::cl::SearchResult SRes;
+
+  // First try config file specified in command line. It has higher priority
+  // than any other way to specify configuration.
+  SRes = llvm::cl::findConfigFileFromArgs(ConfigFile, argv, SearchDirs, true);
+  if (llvm::cl::checkConfigFileSearchResult(SRes, ConfigFile, SearchDirs, true,
+                                            ProgName))
+    return 1;
+
+  // If config file is not specified explicitly, try to determine configuration
+  // implicitly. First try to deduce configuration from executable name. For
+  // instance, a file 'armv7l-clang' applies config file 'armv7l.cfg'. Second,
+  // try to find file 'clang.cfg'.
+  if (SRes == llvm::cl::SearchResult::NotSpecified) {
+    if (findConfigFileFromProgramName(ConfigFile, ProgName))
+      SRes = llvm::cl::SearchResult::Successful;
+  }
+
+  if (SRes == llvm::cl::SearchResult::Successful) {
+    unsigned NumOpts;
+    llvm::cl::readConfigFile(ConfigFile, Saver, argv, NumOpts);
+  }
+
   // Parse response files using the GNU syntax, unless we're in CL mode. There
   // are two ways to put clang in CL compatibility mode: argv[0] is either
   // clang-cl or cl, or --driver-mode=cl is on the command line. The normal
@@ -446,6 +500,8 @@
   ProcessWarningOptions(Diags, *DiagOpts, /*ReportDiags=*/false);
 
   Driver TheDriver(Path, llvm::sys::getDefaultTargetTriple(), Diags);
+  if (!ConfigFile.empty())
+    TheDriver.setConfigFile(ConfigFile.str());
   SetInstallDir(argv, TheDriver, CanonicalPrefixes);
 
   insertTargetAndModeArgs(TargetAndMode.first, TargetAndMode.second, argv,