diff --git a/clang/tools/scan-build/libexec/ccc-analyzer b/clang/tools/scan-build/libexec/ccc-analyzer
@@ -201,7 +201,13 @@ sub GetCCArgs {
   $line =~ s/^\s+|\s+$//g;
   my @items = quotewords('\s+', 0, $line);
   my $cmd = shift @items;
-  die "cannot find 'clang' in 'clang' command\n" if (!($cmd =~ /clang/));
+  die "cannot find 'clang' in 'clang' command\n" if (!($cmd =~ /clang/ || basename($cmd) =~ /llvm/));
+  # If this is the llvm-driver the internal command will look like "llvm clang ...".
+  # Later this will be invoked like "clang clang ...", so skip over it.
+  if (basename($cmd) =~ /llvm/) {
+    die "Expected first arg to llvm driver to be 'clang'" if $items[0] ne "clang";
+    shift @items;
+  }
   return \@items;
 }
 

diff --git a/lld/tools/lld/lld.cpp b/lld/tools/lld/lld.cpp
@@ -36,6 +36,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/CrashRecoveryContext.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/PluginLoader.h"
 #include "llvm/Support/Process.h"
@@ -214,7 +215,7 @@ static unsigned inTestVerbosity() {
   return v;
 }
 
-int lld_main(int argc, char **argv) {
+int lld_main(int argc, char **argv, const llvm::ToolContext &) {
   InitLLVM x(argc, argv);
   sys::Process::UseANSIEscapeCodes(true);
 

diff --git a/llvm/cmake/modules/llvm-driver-template.cpp.in b/llvm/cmake/modules/llvm-driver-template.cpp.in
@@ -6,6 +6,11 @@
 //
 //===----------------------------------------------------------------------===//
 
-int @TOOL_NAME@_main(int argc, char **argv);
+#include "llvm/Support/LLVMDriver.h"
+#include "llvm/ADT/ArrayRef.h"
 
-int main(int argc, char **argv) { return @TOOL_NAME@_main(argc, argv); }
+int @TOOL_NAME@_main(int argc, char **, const llvm::ToolContext &);
+
+int main(int argc, char **argv) {
+  return @TOOL_NAME@_main(argc, argv, {argv[0], nullptr, false});
+}
diff --git a/llvm/include/llvm/Support/LLVMDriver.h b/llvm/include/llvm/Support/LLVMDriver.h
@@ -0,0 +1,29 @@
+//===- LLVMDriver.h ---------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_LLVMDRIVER_H
+#define LLVM_SUPPORT_LLVMDRIVER_H
+
+#include "llvm/ADT/SmallVector.h"
+
+namespace llvm {
+
+struct ToolContext {
+  const char *Path;
+  const char *PrependArg;
+  // PrependArg will be added unconditionally by the llvm-driver, but
+  // NeedsPrependArg will be false if Path is adequate to reinvoke the tool.
+  // This is useful if realpath is ever called on Path, in which case it will
+  // point to the llvm-driver executable, where PrependArg will be needed to
+  // invoke the correct tool.
+  bool NeedsPrependArg;
+};
+
+} // namespace llvm
+
+#endif
diff --git a/llvm/lib/Support/Path.cpp b/llvm/lib/Support/Path.cpp
@@ -1202,18 +1202,10 @@ Error readNativeFileToEOF(file_t FileHandle, SmallVectorImpl<char> &Buffer,
 #include "Windows/Path.inc"
 #endif
 
-bool IsLLVMDriver = false;
-
 namespace llvm {
 namespace sys {
 namespace fs {
 
-std::string getMainExecutable(const char *Argv0, void *MainAddr) {
-  if (IsLLVMDriver)
-    return sys::path::stem(Argv0).str();
-  return getMainExecutableImpl(Argv0, MainAddr);
-}
-
 TempFile::TempFile(StringRef Name, int FD)
     : TmpName(std::string(Name)), FD(FD) {}
 TempFile::TempFile(TempFile &&Other) { *this = std::move(Other); }

diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
@@ -190,7 +190,7 @@ static char *getprogpath(char ret[PATH_MAX], const char *bin) {
 
 /// GetMainExecutable - Return the path to the main executable, given the
 /// value of argv[0] from program startup.
-std::string getMainExecutableImpl(const char *argv0, void *MainAddr) {
+std::string getMainExecutable(const char *argv0, void *MainAddr) {
 #if defined(__APPLE__)
   // On OS X the executable path is saved to the stack by dyld. Reading it
   // from there is much faster than calling dladdr, especially for large

diff --git a/llvm/lib/Support/Windows/Path.inc b/llvm/lib/Support/Windows/Path.inc
@@ -130,7 +130,7 @@ namespace fs {
 
 const file_t kInvalidFile = INVALID_HANDLE_VALUE;
 
-std::string getMainExecutableImpl(const char *argv0, void *MainExecAddr) {
+std::string getMainExecutable(const char *argv0, void *MainExecAddr) {
   SmallVector<wchar_t, MAX_PATH> PathName;
   PathName.resize_for_overwrite(PathName.capacity());
   DWORD Size = ::GetModuleFileNameW(NULL, PathName.data(), PathName.size());

diff --git a/llvm/tools/dsymutil/CMakeLists.txt b/llvm/tools/dsymutil/CMakeLists.txt
@@ -41,4 +41,4 @@ if(APPLE)
   target_link_libraries(dsymutil PRIVATE "-framework CoreFoundation")
 endif(APPLE)
 
-target_link_libraries(dsymutil PRIVATE ${LLVM_ATOMIC_LIB})
+# target_link_libraries(dsymutil PRIVATE ${LLVM_ATOMIC_LIB})
diff --git a/llvm/tools/dsymutil/dsymutil.cpp b/llvm/tools/dsymutil/dsymutil.cpp
@@ -36,6 +36,7 @@
 #include "llvm/Support/FileCollector.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/ThreadPool.h"

diff --git a/llvm/tools/llvm-ar/llvm-ar.cpp b/llvm/tools/llvm-ar/llvm-ar.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Support/Format.h"
 #include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/LineIterator.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
@@ -1425,7 +1426,7 @@ static int ranlib_main(int argc, char **argv) {
   return 0;
 }
 
-int llvm_ar_main(int argc, char **argv) {
+int llvm_ar_main(int argc, char **argv, const llvm::ToolContext &) {
   InitLLVM X(argc, argv);
   ToolName = argv[0];
 

diff --git a/llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp b/llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
@@ -13,6 +13,7 @@
 #include "llvm/Option/Option.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/WithColor.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/TargetParser/Host.h"
@@ -145,7 +146,7 @@ static void demangleLine(llvm::raw_ostream &OS, StringRef Mangled, bool Split) {
   OS.flush();
 }
 
-int llvm_cxxfilt_main(int argc, char **argv) {
+int llvm_cxxfilt_main(int argc, char **argv, const llvm::ToolContext &) {
   InitLLVM X(argc, argv);
   BumpPtrAllocator A;
   StringSaver Saver(A);

diff --git a/llvm/tools/llvm-driver/llvm-driver.cpp b/llvm/tools/llvm-driver/llvm-driver.cpp
@@ -11,12 +11,14 @@
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/WithColor.h"
 
 using namespace llvm;
 
-#define LLVM_DRIVER_TOOL(tool, entry) int entry##_main(int argc, char **argv);
+#define LLVM_DRIVER_TOOL(tool, entry)                                          \
+  int entry##_main(int argc, char **argv, const llvm::ToolContext &);
 #include "LLVMDriverTools.def"
 
 constexpr char subcommands[] =
@@ -34,7 +36,7 @@ static void printHelpMessage() {
                << "OPTIONS:\n\n  --help - Display this message";
 }
 
-static int findTool(int Argc, char **Argv) {
+static int findTool(int Argc, char **Argv, const char *Argv0) {
   if (!Argc) {
     printHelpMessage();
     return 1;
@@ -60,21 +62,22 @@ static int findTool(int Argc, char **Argv) {
     return false;
   };
 
+  auto MakeDriverArgs = [=]() -> llvm::ToolContext {
+    if (ToolName != Argv0)
+      return {Argv0, ToolName.data(), true};
+    return {Argv0, sys::path::filename(Argv0).data(), false};
+  };
+
 #define LLVM_DRIVER_TOOL(tool, entry)                                          \
   if (Is(tool))                                                                \
-    return entry##_main(Argc, Argv);
+    return entry##_main(Argc, Argv, MakeDriverArgs());
 #include "LLVMDriverTools.def"
 
   if (Is("llvm"))
-    return findTool(Argc - 1, Argv + 1);
+    return findTool(Argc - 1, Argv + 1, Argv0);
 
   printHelpMessage();
   return 1;
 }
 
-extern bool IsLLVMDriver;
-
-int main(int Argc, char **Argv) {
-  IsLLVMDriver = true;
-  return findTool(Argc, Argv);
-}
+int main(int Argc, char **Argv) { return findTool(Argc, Argv, Argv[0]); }
diff --git a/llvm/tools/llvm-ifs/llvm-ifs.cpp b/llvm/tools/llvm-ifs/llvm-ifs.cpp
@@ -22,6 +22,7 @@
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileOutputBuffer.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/VersionTuple.h"
@@ -382,7 +383,7 @@ static DriverConfig parseArgs(int argc, char *const *argv) {
   return Config;
 }
 
-int llvm_ifs_main(int argc, char **argv) {
+int llvm_ifs_main(int argc, char **argv, const llvm::ToolContext &) {
   DriverConfig Config = parseArgs(argc, argv);
 
   if (Config.InputFilePaths.empty())

diff --git a/llvm/tools/llvm-lipo/llvm-lipo.cpp b/llvm/tools/llvm-lipo/llvm-lipo.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileOutputBuffer.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/WithColor.h"
 #include "llvm/TargetParser/Triple.h"
@@ -723,7 +724,7 @@ replaceSlices(LLVMContext &LLVMCtx,
   exit(EXIT_SUCCESS);
 }
 
-int llvm_lipo_main(int argc, char **argv) {
+int llvm_lipo_main(int argc, char **argv, const llvm::ToolContext &) {
   InitLLVM X(argc, argv);
   llvm::InitializeAllTargetInfos();
   llvm::InitializeAllTargetMCs();

diff --git a/llvm/tools/llvm-mt/llvm-mt.cpp b/llvm/tools/llvm-mt/llvm-mt.cpp
@@ -17,6 +17,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileOutputBuffer.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/PrettyStackTrace.h"
@@ -82,7 +83,7 @@ static void error(Error EC) {
     });
 }
 
-int llvm_mt_main(int Argc, char **Argv) {
+int llvm_mt_main(int Argc, char **Argv, const llvm::ToolContext &) {
   InitLLVM X(Argc, Argv);
 
   CvtResOptTable T;

diff --git a/llvm/tools/llvm-nm/llvm-nm.cpp b/llvm/tools/llvm-nm/llvm-nm.cpp
@@ -40,6 +40,7 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/Signals.h"
@@ -2286,7 +2287,7 @@ exportSymbolNamesFromFiles(const std::vector<std::string> &InputFilenames) {
   printExportSymbolList(SymbolList);
 }
 
-int llvm_nm_main(int argc, char **argv) {
+int llvm_nm_main(int argc, char **argv, const llvm::ToolContext &) {
   InitLLVM X(argc, argv);
   BumpPtrAllocator A;
   StringSaver Saver(A);

diff --git a/llvm/tools/llvm-objcopy/llvm-objcopy.cpp b/llvm/tools/llvm-objcopy/llvm-objcopy.cpp
@@ -43,6 +43,7 @@
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/FileUtilities.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/Memory.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Process.h"
@@ -223,7 +224,7 @@ static Error executeObjcopy(ConfigManager &ConfigMgr) {
   return Error::success();
 }
 
-int llvm_objcopy_main(int argc, char **argv) {
+int llvm_objcopy_main(int argc, char **argv, const llvm::ToolContext &) {
   InitLLVM X(argc, argv);
   ToolName = argv[0];
 

diff --git a/llvm/tools/llvm-profdata/llvm-profdata.cpp b/llvm/tools/llvm-profdata/llvm-profdata.cpp
@@ -30,6 +30,7 @@
 #include "llvm/Support/Format.h"
 #include "llvm/Support/FormattedStream.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/MD5.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
@@ -2988,7 +2989,8 @@ static int show_main(int argc, const char *argv[]) {
   return showMemProfProfile(Filename, ProfiledBinary, SFormat, OS);
 }
 
-int llvm_profdata_main(int argc, char **argvNonConst) {
+int llvm_profdata_main(int argc, char **argvNonConst,
+                       const llvm::ToolContext &) {
   const char **argv = const_cast<const char **>(argvNonConst);
   InitLLVM X(argc, argv);
 

diff --git a/llvm/tools/llvm-rc/llvm-rc.cpp b/llvm/tools/llvm-rc/llvm-rc.cpp
@@ -25,6 +25,7 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/FileUtilities.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/PrettyStackTrace.h"
@@ -734,7 +735,7 @@ void doCvtres(std::string Src, std::string Dest, std::string TargetTriple) {
 
 } // anonymous namespace
 
-int llvm_rc_main(int Argc, char **Argv) {
+int llvm_rc_main(int Argc, char **Argv, const llvm::ToolContext &) {
   InitLLVM X(Argc, Argv);
   ExitOnErr.setBanner("llvm-rc: ");
 

diff --git a/llvm/tools/llvm-readobj/llvm-readobj.cpp b/llvm/tools/llvm-readobj/llvm-readobj.cpp
@@ -43,6 +43,7 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Support/WithColor.h"
@@ -632,7 +633,7 @@ std::unique_ptr<ScopedPrinter> createWriter() {
   return std::make_unique<ScopedPrinter>(fouts());
 }
 
-int llvm_readobj_main(int argc, char **argv) {
+int llvm_readobj_main(int argc, char **argv, const llvm::ToolContext &) {
   InitLLVM X(argc, argv);
   BumpPtrAllocator A;
   StringSaver Saver(A);

diff --git a/llvm/tools/llvm-size/llvm-size.cpp b/llvm/tools/llvm-size/llvm-size.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/LLVMDriver.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/WithColor.h"
 #include "llvm/Support/raw_ostream.h"
@@ -869,7 +870,7 @@ static void printBerkeleyTotals() {
          << "(TOTALS)\n";
 }
 
-int llvm_size_main(int argc, char **argv) {
+int llvm_size_main(int argc, char **argv, const llvm::ToolContext &) {
   InitLLVM X(argc, argv);
   BumpPtrAllocator A;
   StringSaver Saver(A);