Add support for unittest inputs.

Occasionally it is useful to have unittest which take inputs.
While we normally try to have this test be more of a lit test
we occasionally don't have tools that can exercise the code
in the right way to test certain things.  LLDB has been using
this style of unit test for a while, particularly with regards
to how it tests core dump and minidump file parsing.  Recently
i needed this as well for the case where we want to test that
some of the PDB reading code works correctly.  It needs to
exercise the code in a way that is not covered by any dumper
and would be impractical to implement in one of the dumpers,
but requires a valid PDB file.  Since this is now needed by
more than one project, it makes sense to have this be a
generally supported thing that unit tests can do, and we just
encourage people to use this sparingly.

Differential Revision: https://reviews.llvm.org/D51561

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341502 91177308-0d34-0410-b5e6-96231b3b80d8

cmake/modules/AddLLVM.cmake

@@ -1112,6 +1112,11 @@ function(add_unittest test_suite test_name)
   # executable must be linked with it in order to provide consistent
   # API for all shared libaries loaded by this executable.
   target_link_libraries(${test_name} PRIVATE gtest_main gtest ${LLVM_PTHREAD_LIB})
+  
+  set(LLVM_UNITTEST_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+  configure_file(
+    ${LLVM_MAIN_SRC_DIR}/unittests/unittest.cfg.in
+    ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}/llvm.srcdir.txt)
 
   add_dependencies(${test_suite} ${test_name})
   get_target_property(test_suite_folder ${test_suite} FOLDER)
@@ -1120,6 +1125,7 @@ function(add_unittest test_suite test_name)
   endif ()
 endfunction()
 
+
 # Generic support for adding a benchmark.
 function(add_benchmark benchmark_name)
   if( NOT LLVM_BUILD_BENCHMARKS )

include/llvm/Testing/Support/SupportHelpers.h

@@ -10,10 +10,12 @@
 #ifndef LLVM_TESTING_SUPPORT_SUPPORTHELPERS_H
 #define LLVM_TESTING_SUPPORT_SUPPORTHELPERS_H
 
-#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/Support/Error.h"
 #include "gtest/gtest-printers.h"
 
+#include <string>
+
 namespace llvm {
 namespace detail {
 struct ErrorHolder {
@@ -52,6 +54,10 @@ void PrintTo(const ExpectedHolder<T> &Item, std::ostream *Out) {
   }
 }
 } // namespace detail
+
+namespace unittest {
+SmallString<128> getInputFileDirectory();
+}
 } // namespace llvm
 
 #endif

lib/Testing/Support/CMakeLists.txt

@@ -3,6 +3,7 @@ add_definitions(-DGTEST_HAS_TR1_TUPLE=0)
 
 add_llvm_library(LLVMTestingSupport
   Error.cpp
+  SupportHelpers.cpp
 
   BUILDTREE_ONLY
   

lib/Testing/Support/SupportHelpers.cpp

@@ -0,0 +1,36 @@
+
+#include "llvm/Testing/Support/SupportHelpers.h"
+
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
+
+#include "gtest/gtest.h"
+
+using namespace llvm;
+using namespace llvm::unittest;
+
+extern const char *TestMainArgv0;
+
+SmallString<128> llvm::unittest::getInputFileDirectory() {
+  llvm::SmallString<128> Result = llvm::sys::path::parent_path(TestMainArgv0);
+  llvm::sys::fs::make_absolute(Result);
+  llvm::sys::path::append(Result, "llvm.srcdir.txt");
+
+  EXPECT_TRUE(llvm::sys::fs::is_directory(Result))
+      << "Unit test source directory file does not exist.";
+
+  auto File = MemoryBuffer::getFile(Result);
+
+  EXPECT_TRUE(static_cast<bool>(File))
+      << "Could not open unit test source directory file.";
+
+  Result.clear();
+  Result.append((*File)->getBuffer().trim());
+  llvm::sys::path::append(Result, "Inputs");
+  llvm::sys::path::native(Result);
+  return std::move(Result);
+}

unittests/unittest.cfg.in

@@ -0,0 +1 @@
+@LLVM_UNITTEST_SOURCE_DIR@