LibDriver: Fix output path inference.

The inferred output file name is based on the first input file, not the
first one with extension .obj. The output file was also being written to
the wrong directory; it needs to be written to whichever directory on the
libpath it was found in. This change fixes both issues.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241710 91177308-0d34-0410-b5e6-96231b3b80d8

Author: pcc

lib/LibDriver/LibDriver.cpp

@@ -56,17 +56,13 @@ class LibOptTable : public llvm::opt::OptTable {
 
 }
 
-static std::string getOutputPath(llvm::opt::InputArgList *Args) {
+static std::string getOutputPath(llvm::opt::InputArgList *Args,
+                                 const llvm::NewArchiveIterator &FirstMember) {
   if (auto *Arg = Args->getLastArg(OPT_out))
     return Arg->getValue();
-  for (auto *Arg : Args->filtered(OPT_INPUT)) {
-    if (!StringRef(Arg->getValue()).endswith_lower(".obj"))
-      continue;
-    SmallString<128> Val = StringRef(Arg->getValue());
-    llvm::sys::path::replace_extension(Val, ".lib");
-    return Val.str();
-  }
-  llvm_unreachable("internal error");
+  SmallString<128> Val = FirstMember.getNew();
+  llvm::sys::path::replace_extension(Val, ".lib");
+  return Val.str();
 }
 
 static std::vector<StringRef> getSearchPaths(llvm::opt::InputArgList *Args,
@@ -143,8 +139,8 @@ int llvm::libDriverMain(llvm::ArrayRef<const char*> ArgsArr) {
                          llvm::sys::path::filename(Arg->getValue()));
   }
 
-  std::pair<StringRef, std::error_code> Result =
-      llvm::writeArchive(getOutputPath(&Args), Members, /*WriteSymtab=*/true);
+  std::pair<StringRef, std::error_code> Result = llvm::writeArchive(
+      getOutputPath(&Args, Members[0]), Members, /*WriteSymtab=*/true);
   if (Result.second) {
     if (Result.first.empty())
       Result.first = ArgsArr[0];

test/LibDriver/infer-output-path.test

@@ -0,0 +1,15 @@
+RUN: llvm-mc -triple=x86_64-pc-windows-msvc -filetype=obj -o %T/a.obj %S/Inputs/a.s
+RUN: llvm-mc -triple=x86_64-pc-windows-msvc -filetype=obj -o %T/b.o %S/Inputs/b.s
+RUN: llvm-mc -triple=x86_64-pc-windows-msvc -filetype=obj -o %T/c %S/Inputs/b.s
+
+RUN: rm -f %T/a.lib
+RUN: llvm-lib %T/a.obj
+RUN: test -e %T/a.lib
+
+RUN: rm -f %T/b.lib
+RUN: llvm-lib /libpath:%T b.o
+RUN: test -e %T/b.lib
+
+RUN: rm -f %T/c.lib
+RUN: llvm-lib /libpath:%T c
+RUN: test -e %T/c.lib