better tests and use min length for memcpy

Author: yiwu0b11

flang/include/flang/Runtime/character.h

@@ -10,8 +10,9 @@
 #ifndef CHARACTER_H
 #define CHARACTER_H
 
-#include <cstddef>
 #include <algorithm>
+#include <cstddef>
+#include <cstring>
 
 template <typename TO, typename FROM>
 void CopyAndPad(
@@ -27,7 +28,7 @@ void CopyAndPad(
   } else if (toChars <= fromChars) {
     std::memcpy(to, from, toChars * sizeof(TO));
   } else {
-    std::memcpy(to, from, fromChars * sizeof(TO));
+    std::memcpy(to, from, std::min(toChars, fromChars) * sizeof(TO));
     for (std::size_t j{fromChars}; j < toChars; ++j) {
       to[j] = static_cast<TO>(' ');
     }

flang/include/flang/Runtime/extensions.h

@@ -28,6 +28,7 @@ std::int32_t FORTRAN_PROCEDURE_NAME(iargc)();
 void FORTRAN_PROCEDURE_NAME(getarg)(
     std::int32_t &n, std::int8_t *arg, std::int64_t length);
 
+// GNU extension subroutine GETLOG(C).
 void FORTRAN_PROCEDURE_NAME(getlog)(std::int8_t *name, std::int64_t length);
 
 } // extern "C"

flang/runtime/extensions.cpp

@@ -81,7 +81,7 @@ void FORTRAN_PROCEDURE_NAME(getarg)(
 }
 
 void FORTRAN_PROCEDURE_NAME(getlog)(std::int8_t *arg, std::int64_t length) {
-  const int nameMaxLen = LOGIN_NAME_MAX + 1;
+  const int nameMaxLen{LOGIN_NAME_MAX + 1};
   char str[nameMaxLen];
 
   int error{getlogin_r(str, nameMaxLen)};

flang/unittests/Runtime/CMakeLists.txt

@@ -7,6 +7,7 @@ add_flang_unittest(FlangRuntimeTests
   Complex.cpp
   CrashHandlerFixture.cpp
   Derived.cpp
+  ExtensionTest.cpp
   ExternalIOTest.cpp
   Format.cpp
   Inquiry.cpp

flang/unittests/Runtime/CommandTest.cpp

@@ -10,6 +10,7 @@
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include "flang/Runtime/descriptor.h"
+#include "flang/Runtime/extensions.h"
 #include "flang/Runtime/main.h"
 #include <cstdlib>
 
@@ -225,12 +226,6 @@ TEST_F(ZeroArguments, GetCommandArgument) {
   CheckMissingArgumentValue(1);
 }
 
-TEST_F(ZeroArguments, GetLog) {
-  CheckMissingArgumentValue(-1);
-  CheckArgumentValue(commandOnlyArgv[0], 0);
-  CheckMissingArgumentValue(1);
-}
-
 TEST_F(ZeroArguments, GetCommand) { CheckCommandValue(commandOnlyArgv, 1); }
 
 static const char *oneArgArgv[]{"aProgram", "anArgumentOfLength20"};
@@ -248,13 +243,6 @@ TEST_F(OneArgument, GetCommandArgument) {
   CheckMissingArgumentValue(2);
 }
 
-TEST_F(OneArgument, GetLog) {
-  CheckMissingArgumentValue(-1);
-  CheckArgumentValue(oneArgArgv[0], 0);
-  CheckArgumentValue(oneArgArgv[1], 1);
-  CheckMissingArgumentValue(2);
-}
-
 TEST_F(OneArgument, GetCommand) { CheckCommandValue(oneArgArgv, 2); }
 
 static const char *severalArgsArgv[]{

flang/unittests/Runtime/ExtensionTest.cpp

@@ -0,0 +1,48 @@
+//===-- flang/unittests/Runtime/ExtensionTest.cpp
+//---------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "CrashHandlerFixture.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "flang/Runtime/descriptor.h"
+#include "flang/Runtime/extensions.h"
+#include "flang/Runtime/main.h"
+#include <cstdlib>
+
+#ifdef _WIN32
+#include <lmcons.h> // UNLEN=256
+#define LOGIN_NAME_MAX UNLEN
+#else
+#include <limits.h>
+#endif
+
+using namespace Fortran::runtime;
+
+struct ExtensionTests : CrashHandlerFixture {};
+
+TEST_F(ExtensionTests, GetlogGetName) {
+  const int charLen{3};
+  char input[charLen]{"\0\0"};
+
+  FORTRAN_PROCEDURE_NAME(getlog)
+  (reinterpret_cast<std::int8_t *>(input), charLen);
+
+  EXPECT_NE(input[0], '\0');
+}
+
+TEST_F(ExtensionTests, GetlogPadSpace) {
+  const int charLen{LOGIN_NAME_MAX +
+      2}; // guarantee 1 char longer than max, last char should be pad space
+  char input[charLen];
+
+  FORTRAN_PROCEDURE_NAME(getlog)
+  (reinterpret_cast<std::int8_t *>(input), charLen);
+
+  EXPECT_EQ(input[charLen - 1], ' ');
+}