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[flang][runtime] Add ACCESS library procedure #88517

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Merged
merged 6 commits into from
Apr 16, 2024
Merged

[flang][runtime] Add ACCESS library procedure #88517

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f22970a
[flang][runtime] Add ACCESS intrinsic
tblah Mar 26, 2024
dcf7419
Add missing guard to prevent adding code to a Windows build
tblah Apr 12, 2024
98c6f5d
Use braced initialization
tblah Apr 12, 2024
66f32b5
Link std::filesystem
tblah Apr 12, 2024
18f3ff4
Revert "Link std::filesystem"
tblah Apr 15, 2024
c137de6
Remove dependency on std::filesystem
tblah Apr 15, 2024
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8 changes: 8 additions & 0 deletions flang/docs/Intrinsics.md
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Expand Up @@ -657,6 +657,14 @@ CALL CO_REDUCE
CALL CO_SUM
```

### Inquiry Functions
ACCESS (GNU extension) is not supported on Windows. Otherwise:
```
CHARACTER(LEN=*) :: path = 'path/to/file'
IF (ACCESS(path, 'rwx')) &
...
```

## Non-standard intrinsics
### PGI
```
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7 changes: 7 additions & 0 deletions flang/include/flang/Runtime/extensions.h
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Expand Up @@ -44,5 +44,12 @@ std::int64_t RTNAME(Signal)(std::int64_t number, void (*handler)(int));
// GNU extension subroutine SLEEP(SECONDS)
void RTNAME(Sleep)(std::int64_t seconds);

// GNU extension function ACCESS(NAME, MODE)
// TODO: not supported on Windows
#ifndef _WIN32
std::int64_t FORTRAN_PROCEDURE_NAME(access)(const char *name,
std::int64_t nameLength, const char *mode, std::int64_t modeLength);
#endif

} // extern "C"
#endif // FORTRAN_RUNTIME_EXTENSIONS_H_
73 changes: 73 additions & 0 deletions flang/runtime/extensions.cpp
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Expand Up @@ -17,6 +17,7 @@
#include "flang/Runtime/entry-names.h"
#include "flang/Runtime/io-api.h"
#include <chrono>
#include <cstring>
#include <ctime>
#include <signal.h>
#include <thread>
Expand Down Expand Up @@ -138,5 +139,77 @@ void RTNAME(Sleep)(std::int64_t seconds) {
std::this_thread::sleep_for(std::chrono::seconds(seconds));
}

// TODO: not supported on Windows
#ifndef _WIN32
std::int64_t FORTRAN_PROCEDURE_NAME(access)(const char *name,
std::int64_t nameLength, const char *mode, std::int64_t modeLength) {
std::int64_t ret{-1};
if (nameLength <= 0 || modeLength <= 0 || !name || !mode) {
return ret;
}

// ensure name is null terminated
char *newName{nullptr};
if (name[nameLength - 1] != '\0') {
newName = static_cast<char *>(std::malloc(nameLength + 1));
std::memcpy(newName, name, nameLength);
newName[nameLength] = '\0';
name = newName;
}

// calculate mode
bool read{false};
bool write{false};
bool execute{false};
bool exists{false};
int imode{0};

for (std::int64_t i = 0; i < modeLength; ++i) {
switch (mode[i]) {
case 'r':
read = true;
break;
case 'w':
write = true;
break;
case 'x':
execute = true;
break;
case ' ':
exists = true;
break;
default:
// invalid mode
goto cleanup;
}
}
if (!read && !write && !execute && !exists) {
// invalid mode
goto cleanup;
}

if (!read && !write && !execute) {
imode = F_OK;
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Using F_OK and related constants means that unistd.h needs to be included unconditionally, otherwise at least FreeBSD is broken.

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Thank you for reporting the issue. Does this fix the problem for you? 2583b2e

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The latest in main does, thanks!

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Looks like POSIX says access and F_OK related constants are in unistd.h, but faccessat is in fcntl.h. I did a small amount of digging, and glibc defines F_OK in both unistd.h and fcntl.h, as does musl. FreeBSD and NetBSD only define them in unistd.h. Didn't check any other systems.

} else {
if (read) {
imode |= R_OK;
}
if (write) {
imode |= W_OK;
}
if (execute) {
imode |= X_OK;
}
}
ret = access(name, imode);

cleanup:
if (newName) {
free(newName);
}
return ret;
}
#endif

} // namespace Fortran::runtime
} // extern "C"
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