Make clang-cl accept .lib inputs

[• ehsan]

Summary

This enables passing in the names of libraries found in the system LIB paths to cl.exe, and verifies that such libraries are passed to the linker.

[hans]

Thanks for the patch! Just some cosmetic comments:

lib/Driver/Driver.cpp

934

I would have gone for a name such as "ExistsInLibDir".

935

This is copied from FindFallback in Tools.cpp. Maybe we should think about a way to factor this out into some utility in llvm::sys.. no need to block this patch on that, though.

I think some of the names could be improved, though. PathSegments below could be better named as LibDirs, for example.

948

Maybe use a range-based for loop?

984

Since this is a clang-cl specific thing, we should guard this check with "D.IsCLMode()".

[• ehsan]

Addressed the review comments. I'll work on refactoring this utility function later.

[hans]

lgtm

[hans]

Closed by commit rL211189 (authored by @hans).

lib/Driver/Driver.cpp

 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Job.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/Tool.h"
 #include "clang/Driver/ToolChain.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/OptSpecifier.h"
 #include "llvm/Option/OptTable.h"
 #include "llvm/Option/Option.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/Process.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/raw_ostream.h"
 #include <map>
 #include <memory>
 
 using namespace clang::driver;
 using namespace clang;
 using namespace llvm::opt;
if (A && !A->getOption().matches(options::OPT_g0) &&
         Actions.pop_back();
         Actions.push_back(new VerifyDebugInfoJobAction(VerifyInput,
                                                        types::TY_Nothing));
       }
     }
   }
 }
 
+/// \brief Check whether the file referenced by Value exists in the LIB
+/// environment variable.
+static bool ExistsInLibDir(StringRef Value) {
+  llvm::Optional<std::string> OptPath = llvm::sys::Process::GetEnv("LIB");
+  if (!OptPath.hasValue())
+    return false;
+
+#ifdef LLVM_ON_WIN32
+  const StringRef PathSeparators = ";";
+#else
+  const StringRef PathSeparators = ":";
+#endif
+
+  SmallVector<StringRef, 8> LibDirs;
+  llvm::SplitString(OptPath.getValue(), LibDirs, PathSeparators);
+
+  for (const auto &PathSegment : LibDirs) {
+    if (PathSegment.empty())
+      continue;
+
+    SmallString<128> FilePath(PathSegment);
+    llvm::sys::path::append(FilePath, Value);
+    if (llvm::sys::fs::exists(Twine(FilePath)))
+      return true;
+  }
+
+  return false;
+}
+
 /// \brief Check that the file referenced by Value exists. If it doesn't,
 /// issue a diagnostic and return false.
 static bool DiagnoseInputExistence(const Driver &D, const DerivedArgList &Args,
                                    StringRef Value) {
   if (!D.getCheckInputsExist())
     return true;
 
   // stdin always exists.
   if (Value == "-")
     return true;
 
   SmallString<64> Path(Value);
   if (Arg *WorkDir = Args.getLastArg(options::OPT_working_directory)) {
     if (!llvm::sys::path::is_absolute(Path.str())) {
       SmallString<64> Directory(WorkDir->getValue());
       llvm::sys::path::append(Directory, Value);
       Path.assign(Directory);
     }
   }
 
   if (llvm::sys::fs::exists(Twine(Path)))
     return true;
 
+  if (D.IsCLMode() && ExistsInLibDir(Value))
+    return true;
+
   D.Diag(clang::diag::err_drv_no_such_file) << Path.str();
   return false;
 }
 
 // Construct a the list of inputs and their types.
 void Driver::BuildInputs(const ToolChain &TC, DerivedArgList &Args,
                          InputList &Inputs) const {
   // Track the current user specified (-x) input. We also explicitly track the

test/Driver/cl-inputs.c

 // WARN-NOT: note
 
 // RUN: not %clang_cl - 2>&1 | FileCheck -check-prefix=STDIN %s
 // STDIN: error: use /Tc or /Tp
 
 // RUN: %clang_cl -### /Tc - 2>&1 | FileCheck -check-prefix=STDINTc %s
 // STDINTc: "-x" "c"
 
+// RUN: env LIB=%S/Inputs/cl-libs %clang_cl -### -- %s cl-test.lib 2>&1 | FileCheck -check-prefix=LIBINPUT %s
+// LIBINPUT: "link.exe"
+// LIBINPUT: "cl-test.lib"
+
+// RUN: env LIB=%S/Inputs/cl-libs %clang_cl -### -- %s cl-test2.lib 2>&1 | FileCheck -check-prefix=LIBINPUT2 %s
+// LIBINPUT2: error: no such file or directory: 'cl-test2.lib'
+// LIBINPUT2: "link.exe"
+// LIBINPUT2-NOT: "cl-test2.lib"
+
 void f();