From 12f4f8be904b16855952b0ea0355107b508cfbc3 Mon Sep 17 00:00:00 2001
From: Hans Wennborg <hans@hanshq.net>
Date: Fri, 15 Apr 2016 01:12:32 +0000
Subject: [PATCH] clang-cl: Don't check for existence of linker inputs when
 /link is used

There might be flags passed to the linker (e.g. /libpath), causing it
to search in paths the Clang driver doesn't know about.

PR27234

llvm-svn: 266402
---
 clang/lib/Driver/Driver.cpp | 23 ++++++++++++++++-------
 clang/test/Driver/cl-link.c |  8 ++++++++
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 64903de..9894323 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1115,7 +1115,7 @@ void Driver::BuildUniversalActions(Compilation &C, const ToolChain &TC,
 /// \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) {
+                                   StringRef Value, types::ID Ty) {
   if (!D.getCheckInputsExist())
     return true;
 
@@ -1135,9 +1135,18 @@ static bool DiagnoseInputExistence(const Driver &D, const DerivedArgList &Args,
   if (llvm::sys::fs::exists(Twine(Path)))
     return true;
 
-  if (D.IsCLMode() && !llvm::sys::path::is_absolute(Twine(Path)) &&
-      llvm::sys::Process::FindInEnvPath("LIB", Value))
-    return true;
+  if (D.IsCLMode()) {
+    if (!llvm::sys::path::is_absolute(Twine(Path)) &&
+        llvm::sys::Process::FindInEnvPath("LIB", Value))
+      return true;
+
+    if (Args.hasArg(options::OPT__SLASH_link) && Ty == types::TY_Object) {
+      // Arguments to the /link flag might cause the linker to search for object
+      // and library files in paths we don't know about. Don't error in such
+      // cases.
+      return true;
+    }
+  }
 
   D.Diag(clang::diag::err_drv_no_such_file) << Path;
   return false;
@@ -1253,19 +1262,19 @@ void Driver::BuildInputs(const ToolChain &TC, DerivedArgList &Args,
         }
       }
 
-      if (DiagnoseInputExistence(*this, Args, Value))
+      if (DiagnoseInputExistence(*this, Args, Value, Ty))
         Inputs.push_back(std::make_pair(Ty, A));
 
     } else if (A->getOption().matches(options::OPT__SLASH_Tc)) {
       StringRef Value = A->getValue();
-      if (DiagnoseInputExistence(*this, Args, Value)) {
+      if (DiagnoseInputExistence(*this, Args, Value, types::TY_C)) {
         Arg *InputArg = MakeInputArg(Args, Opts, A->getValue());
         Inputs.push_back(std::make_pair(types::TY_C, InputArg));
       }
       A->claim();
     } else if (A->getOption().matches(options::OPT__SLASH_Tp)) {
       StringRef Value = A->getValue();
-      if (DiagnoseInputExistence(*this, Args, Value)) {
+      if (DiagnoseInputExistence(*this, Args, Value, types::TY_CXX)) {
         Arg *InputArg = MakeInputArg(Args, Opts, A->getValue());
         Inputs.push_back(std::make_pair(types::TY_CXX, InputArg));
       }
diff --git a/clang/test/Driver/cl-link.c b/clang/test/Driver/cl-link.c
index b3c0b64..026c433 100644
--- a/clang/test/Driver/cl-link.c
+++ b/clang/test/Driver/cl-link.c
@@ -43,3 +43,11 @@
 // RUN: %clang_cl /Zi /Tc%s -### 2>&1 | FileCheck --check-prefix=DEBUG %s
 // DEBUG: link.exe
 // DEBUG: "-debug"
+
+// PR27234
+// RUN: %clang_cl /Tc%s nonexistent.obj -### /link /libpath:somepath 2>&1 | FileCheck --check-prefix=NONEXISTENT %s
+// RUN: %clang_cl /Tc%s nonexistent.lib -### /link /libpath:somepath 2>&1 | FileCheck --check-prefix=NONEXISTENT %s
+// NONEXISTENT-NOT: no such file
+// NONEXISTENT: link.exe
+// NONEXISTENT: "/libpath:somepath"
+// NONEXISTENT: nonexistent
-- 
2.7.4