[flang] Basic tests of external I/O runtime (part 9/9)

Add new unit tests for external Fortran I/O that drive the
Fortran I/O runtime API from C++ and exercise basic writing
and read-back in the various combinations of access modes,
record length variability, and formatting.  Sequential modes
are tested with positioning.  More thorough tests written in
Fortran will follow when they can be compiled and run.

The Fortran runtime's error termination callback registration
was extended with source file and line number positions for
better failure messages in unit testing.

Reviewed By: sscalpone

Differential Revision: https://reviews.llvm.org/D83164

Author: klausler

flang/runtime/terminator.cpp

@@ -18,17 +18,18 @@ namespace Fortran::runtime {
   CrashArgs(message, ap);
 }
 
-static void (*crashHandler)(const char *, va_list &){nullptr};
+static void (*crashHandler)(const char *, int, const char *, va_list &){
+    nullptr};
 
 void Terminator::RegisterCrashHandler(
-    void (*handler)(const char *, va_list &)) {
+    void (*handler)(const char *, int, const char *, va_list &)) {
   crashHandler = handler;
 }
 
 [[noreturn]] void Terminator::CrashArgs(
     const char *message, va_list &ap) const {
   if (crashHandler) {
-    crashHandler(message, ap);
+    crashHandler(sourceFileName_, sourceLine_, message, ap);
   }
   std::fputs("\nfatal Fortran runtime error", stderr);
   if (sourceFileName_) {

flang/runtime/terminator.h

@@ -34,7 +34,8 @@ class Terminator {
       const char *predicate, const char *file, int line) const;
 
   // For test harnessing - overrides CrashArgs().
-  static void RegisterCrashHandler(void (*)(const char *, va_list &));
+  static void RegisterCrashHandler(void (*)(const char *sourceFile,
+      int sourceLine, const char *message, va_list &ap));
 
 private:
   const char *sourceFileName_{nullptr};

flang/unittests/Runtime/CMakeLists.txt

@@ -41,6 +41,18 @@ target_link_libraries(external-hello-world
   LLVMSupport
 )
 
+add_executable(external-io
+  external-io.cpp
+)
+
+target_link_libraries(external-io
+  RuntimeTesting
+  FortranRuntime
+  LLVMSupport
+)
+
+add_test(NAME ExternalIO COMMAND external-io)
+
 add_executable(list-input-test
   list-input.cpp
 )

flang/unittests/Runtime/external-hello.cpp

@@ -5,9 +5,8 @@
 
 using namespace Fortran::runtime::io;
 
-int main(int argc, const char *argv[], const char *envp[]) {
-  RTNAME(ProgramStart)(argc, argv, envp);
-  auto *io{IONAME(BeginExternalListOutput)()};
+void output1() {
+  auto io{IONAME(BeginExternalListOutput)()};
   const char str[]{"Hello, world!"};
   IONAME(OutputAscii)(io, str, std::strlen(str));
   IONAME(OutputInteger64)(io, 678);
@@ -21,6 +20,31 @@ int main(int argc, const char *argv[], const char *envp[]) {
   IONAME(OutputLogical)(io, false);
   IONAME(OutputLogical)(io, true);
   IONAME(EndIoStatement)(io);
+}
+
+void input1() {
+  auto io{IONAME(BeginExternalListOutput)()};
+  const char prompt[]{"Enter an integer value:"};
+  IONAME(OutputAscii)(io, prompt, std::strlen(prompt));
+  IONAME(EndIoStatement)(io);
+
+  io = IONAME(BeginExternalListInput)();
+  std::int64_t n{-666};
+  IONAME(InputInteger)(io, n);
+  IONAME(EndIoStatement)(io);
+
+  io = IONAME(BeginExternalListOutput)();
+  const char str[]{"Result:"};
+  IONAME(OutputAscii)(io, str, std::strlen(str));
+  IONAME(OutputInteger64)(io, n);
+  IONAME(EndIoStatement)(io);
+}
+
+int main(int argc, const char *argv[], const char *envp[]) {
+  RTNAME(ProgramStart)(argc, argv, envp);
+  output1();
+  input1();
+  RTNAME(PauseStatement)();
   RTNAME(ProgramEndStatement)();
   return 0;
 }