996ef895cd
This legacy option (available in other Fortran compilers with various spellings) implies the SAVE attribute for local variables on subprograms that are not explicitly RECURSIVE. The SAVE attribute essentially implies static rather than stack storage. This was the default setting in Fortran until surprisingly recently, so explicit SAVE statements & attributes could be and often were omitted from older codes. Note that initialized objects already have an implied SAVE attribute, and objects in COMMON effectively do too, as data overlays are extinct; and since objects that are expected to survive from one invocation of a procedure to the next in static storage should probably be explicit initialized in the first place, so the use cases for this option are somewhat rare, and all of them could be handled with explicit SAVE statements or attributes. This implicit SAVE attribute must not apply to automatic (in the Fortran sense) local objects, whose sizes cannot be known at compilation time. To get the semantics of IsSaved() right, the IsAutomatic() predicate was moved into Evaluate/tools.cpp to allow for dynamic linking of the compiler. The redundant predicate IsAutomatic() was noticed, removed, and its uses replaced. GNU Fortran's spelling of the option (-fno-automatic) was added to the clang-based driver and used for basic sanity testing. Differential Revision: https://reviews.llvm.org/D114209
30 lines
673 B
Fortran
30 lines
673 B
Fortran
! RUN: %python %S/test_errors.py %s %flang_fc1
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MODULE test
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SAVE
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CONTAINS
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PURE FUNCTION pf( )
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IMPLICIT NONE
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INTEGER :: pf
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INTEGER :: mc
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!OK: SAVE statement is not inherited by the function
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END FUNCTION
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PURE FUNCTION pf2( )
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IMPLICIT NONE
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SAVE
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INTEGER :: pf2
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!ERROR: A pure subprogram may not have a variable with the SAVE attribute
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INTEGER :: mc
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END FUNCTION
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! This same subroutine appears in test save02.f90 where it is not an
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! error due to -fno-automatic.
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SUBROUTINE foo
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INTEGER, TARGET :: t
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!ERROR: An initial data target may not be a reference to an object 't' that lacks the SAVE attribute
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INTEGER, POINTER :: p => t
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end
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END MODULE
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