[flang][runtime] Clean up code to unblock development (#78063)

Clean up recently-added code to avoid warnings and to eliminate a
needless dependence from the Fortran runtime support library on C++
runtimes.

Author: klausler

flang/include/flang/Runtime/extensions.h

@@ -30,10 +30,10 @@ std::int32_t FORTRAN_PROCEDURE_NAME(iargc)();
 
 // GNU Fortran 77 compatibility subroutine GETARG(N, ARG).
 void FORTRAN_PROCEDURE_NAME(getarg)(
-    std::int32_t &n, std::int8_t *arg, std::int64_t length);
+    std::int32_t &n, char *arg, std::int64_t length);
 
 // GNU extension subroutine GETLOG(C).
-void FORTRAN_PROCEDURE_NAME(getlog)(std::byte *name, std::int64_t length);
+void FORTRAN_PROCEDURE_NAME(getlog)(char *name, std::int64_t length);
 
 } // extern "C"
 #endif // FORTRAN_RUNTIME_EXTENSIONS_H_

flang/runtime/execute.cpp

@@ -151,19 +151,19 @@ void RTNAME(ExecuteCommandLine)(const Descriptor &command, bool wait,
 
     // add "cmd.exe /c " to the beginning of command
     const char *prefix{"cmd.exe /c "};
-    char *newCmdWin{(char *)AllocateMemoryOrCrash(
-        terminator, std::strlen(prefix) + std::strlen(newCmd) + 1)};
+    char *newCmdWin{static_cast<char *>(AllocateMemoryOrCrash(
+        terminator, std::strlen(prefix) + std::strlen(newCmd) + 1))};
     std::strcpy(newCmdWin, prefix);
     std::strcat(newCmdWin, newCmd);
 
     // Convert the char to wide char
     const size_t sizeNeeded{mbstowcs(NULL, newCmdWin, 0) + 1};
-    wchar_t *wcmd{(wchar_t *)AllocateMemoryOrCrash(
-        terminator, sizeNeeded * sizeof(wchar_t))};
+    wchar_t *wcmd{static_cast<wchar_t *>(
+        AllocateMemoryOrCrash(terminator, sizeNeeded * sizeof(wchar_t)))};
     if (std::mbstowcs(wcmd, newCmdWin, sizeNeeded) == static_cast<size_t>(-1)) {
       terminator.Crash("Char to wide char failed for newCmd");
     }
-    FreeMemory((void *)newCmdWin);
+    FreeMemory(newCmdWin);
 
     if (CreateProcess(nullptr, wcmd, nullptr, nullptr, FALSE, 0, nullptr,
             nullptr, &si, &pi)) {
@@ -179,7 +179,7 @@ void RTNAME(ExecuteCommandLine)(const Descriptor &command, bool wait,
         CheckAndCopyCharsToDescriptor(cmdmsg, "CreateProcess failed.");
       }
     }
-    FreeMemory((void *)wcmd);
+    FreeMemory(wcmd);
 #else
     // terminated children do not become zombies
     signal(SIGCHLD, SIG_IGN);
@@ -200,7 +200,7 @@ void RTNAME(ExecuteCommandLine)(const Descriptor &command, bool wait,
   }
   // Deallocate memory if EnsureNullTerminated dynamically allocated memory
   if (newCmd != command.OffsetElement()) {
-    FreeMemory((void *)newCmd);
+    FreeMemory(newCmd);
   }
 }
 

flang/runtime/extensions.cpp

@@ -47,8 +47,7 @@ extern "C" {
 
 namespace Fortran::runtime {
 
-void GetUsernameEnvVar(
-    const char *envName, std::byte *arg, std::int64_t length) {
+void GetUsernameEnvVar(const char *envName, char *arg, std::int64_t length) {
   Descriptor name{*Descriptor::Create(
       1, std::strlen(envName) + 1, const_cast<char *>(envName), 0)};
   Descriptor value{*Descriptor::Create(1, length, arg, 0)};
@@ -91,36 +90,23 @@ std::int32_t FORTRAN_PROCEDURE_NAME(iargc)() { return RTNAME(ArgumentCount)(); }
 
 // CALL GETARG(N, ARG)
 void FORTRAN_PROCEDURE_NAME(getarg)(
-    std::int32_t &n, std::int8_t *arg, std::int64_t length) {
+    std::int32_t &n, char *arg, std::int64_t length) {
   Descriptor value{*Descriptor::Create(1, length, arg, 0)};
   (void)RTNAME(GetCommandArgument)(
       n, &value, nullptr, nullptr, __FILE__, __LINE__);
 }
 
 // CALL GETLOG(USRNAME)
-void FORTRAN_PROCEDURE_NAME(getlog)(std::byte *arg, std::int64_t length) {
+void FORTRAN_PROCEDURE_NAME(getlog)(char *arg, std::int64_t length) {
 #if _REENTRANT || _POSIX_C_SOURCE >= 199506L
-  int nameMaxLen;
-#ifdef LOGIN_NAME_MAX
-  nameMaxLen = LOGIN_NAME_MAX + 1;
-#else
-  nameMaxLen = sysconf(_SC_LOGIN_NAME_MAX) + 1;
-  if (nameMaxLen == -1)
-    nameMaxLen = _POSIX_LOGIN_NAME_MAX + 1;
-#endif
-  std::vector<char> str(nameMaxLen);
-
-  int error{getlogin_r(str.data(), nameMaxLen)};
-  if (error == 0) {
-    // no error: find first \0 in string then pad from there
-    CopyAndPad(reinterpret_cast<char *>(arg), str.data(), length,
-        std::strlen(str.data()));
-  } else {
-    // error occur: get username from environment variable
-    GetUsernameEnvVar("LOGNAME", arg, length);
+  if (length >= 1 && getlogin_r(arg, length) == 0) {
+    auto loginLen{std::strlen(arg)};
+    std::memset(
+        arg + loginLen, ' ', static_cast<std::size_t>(length) - loginLen);
+    return;
   }
-#elif _WIN32
-  // Get username from environment to avoid link to Advapi32.lib
+#endif
+#if _WIN32
   GetUsernameEnvVar("USERNAME", arg, length);
 #else
   GetUsernameEnvVar("LOGNAME", arg, length);

flang/unittests/Runtime/CommandTest.cpp

@@ -681,10 +681,7 @@ TEST_F(EnvironmentVariables, ErrMsgTooShort) {
 TEST_F(EnvironmentVariables, GetlogGetName) {
   const int charLen{3};
   char input[charLen]{"\0\0"};
-
-  FORTRAN_PROCEDURE_NAME(getlog)
-  (reinterpret_cast<std::byte *>(input), charLen);
-
+  FORTRAN_PROCEDURE_NAME(getlog)(input, charLen);
   EXPECT_NE(input[0], '\0');
 }
 
@@ -700,10 +697,7 @@ TEST_F(EnvironmentVariables, GetlogPadSpace) {
     charLen = _POSIX_LOGIN_NAME_MAX + 2;
 #endif
   std::vector<char> input(charLen);
-
-  FORTRAN_PROCEDURE_NAME(getlog)
-  (reinterpret_cast<std::byte *>(input.data()), charLen);
-
+  FORTRAN_PROCEDURE_NAME(getlog)(input.data(), charLen);
   EXPECT_EQ(input[charLen - 1], ' ');
 }
 #endif
@@ -715,8 +709,7 @@ TEST_F(EnvironmentVariables, GetlogEnvGetName) {
         << "Environment variable USERNAME does not exist";
 
     char input[]{"XXXXXXXXX"};
-    FORTRAN_PROCEDURE_NAME(getlog)
-    (reinterpret_cast<std::byte *>(input), sizeof(input));
+    FORTRAN_PROCEDURE_NAME(getlog)(input, sizeof(input));
 
     CheckCharEqStr(input, "loginName");
   }
@@ -728,8 +721,7 @@ TEST_F(EnvironmentVariables, GetlogEnvBufferShort) {
         << "Environment variable USERNAME does not exist";
 
     char input[]{"XXXXXX"};
-    FORTRAN_PROCEDURE_NAME(getlog)
-    (reinterpret_cast<std::byte *>(input), sizeof(input));
+    FORTRAN_PROCEDURE_NAME(getlog)(input, sizeof(input));
 
     CheckCharEqStr(input, "loginN");
   }
@@ -741,8 +733,7 @@ TEST_F(EnvironmentVariables, GetlogEnvPadSpace) {
         << "Environment variable USERNAME does not exist";
 
     char input[]{"XXXXXXXXXX"};
-    FORTRAN_PROCEDURE_NAME(getlog)
-    (reinterpret_cast<std::byte *>(input), sizeof(input));
+    FORTRAN_PROCEDURE_NAME(getlog)(input, sizeof(input));
 
     CheckCharEqStr(input, "loginName ");
   }