[PATCH] D103805: [flang] Define the runtime API for CPU_TIME

[Peter Klausler via Phabricator via llvm-commits]

klausler added inline comments.


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Comment at: flang/runtime/time-intrinsic.h:12
+
+#ifndef FORTRAN_RUNTIME_TIME_INTRINSIC_H_
+#define FORTRAN_RUNTIME_TIME_INTRINSIC_H_
----------------
I would consider putting this into the header file with miscellaneous intrinsics... were it not for the problem of SYSTEM_CLOCK (16.9.186), which will also need a home, and whose API might be messy.  DATE_AND_TIME will also need to go here.


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Comment at: flang/runtime/time-intrinsic.h:21
+
+void RTNAME(CpuTime)(CppTypeFor<TypeCategory::Real, 8> &time,
+    const char *sourceFile = nullptr, int line = 0);
----------------
schweitz wrote:
> rovka wrote:
> > IIUC, the default real kind is usually 4, but can be set to 8 with -fdefault-real-8. 
> > 
> > Should we have another overload for CppTypeFor<TypeCategory::Real, 4>, or can we assume that lowering can deal with downcasting if the default kind is 4?
> Lowering handles cases which require floating-point format conversions when calling the runtime. That said, the runtime can (and often does) provide multiple interfaces, which may eliminate the necessity of such conversions.
Lowering can handle data conversions for value arguments and for function results, but reference arguments like CPU_TIME's are somewhat more problematic.  CPU_TIME (16.9.57) is a subroutine, not a function.  But since its sole argument is INTENT(OUT), the API could be a function returning a C double, and lowering could take care of converting and assigning the result. 



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Comment at: flang/runtime/time-intrinsic.h:22
+void RTNAME(CpuTime)(CppTypeFor<TypeCategory::Real, 8> &time,
+    const char *sourceFile = nullptr, int line = 0);
+
----------------
These source position arguments are needed only for runtime APIs that can encounter errors.  CPU_TIME probably can't.


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https://reviews.llvm.org/D103805