Hey guys, I found that Flang's built-in ABORT function is incomplete
when I was using it. Compared with gfortran's ABORT (which can both
abort and print out a backtrace), flang's ABORT implementation lacks the
function of printing out a backtrace. This feature is essential for
debugging and understanding the call stack at the failure point.
To solve this problem, I completed the "// TODO:" of the abort function,
and then implemented an additional built-in function BACKTRACE for
flang. After a brief reading of the relevant source code, I used
backtrace and backtrace_symbols in "execinfo.h" to quickly implement
this. But since I used the above two functions directly, my
implementation is slightly different from gfortran's implementation (in
the output, the function call stack before main is additionally output,
and the function line number is missing). In addition, since I used the
above two functions, I did not need to add -g to embed debug information
into the ELF file, but needed -rdynamic to ensure that the symbols are
added to the dynamic symbol table (so that the function name will be
printed out).
Here is a comparison of the output between gfortran 's backtrace and my
implementation:
gfortran's implemention output:
```
#0 0x557eb71f4184 in testfun2_
at /home/hunter/plct/fortran/test.f90:5
#1 0x557eb71f4165 in testfun1_
at /home/hunter/plct/fortran/test.f90:13
#2 0x557eb71f4192 in test_backtrace
at /home/hunter/plct/fortran/test.f90:17
#3 0x557eb71f41ce in main
at /home/hunter/plct/fortran/test.f90:18
```
my impelmention output:
```
Backtrace:
#0 ./test(_FortranABacktrace+0x32) [0x574f07efcf92]
#1 ./test(testfun2_+0x14) [0x574f07efc7b4]
#2 ./test(testfun1_+0xd) [0x574f07efc7cd]
#3 ./test(_QQmain+0x9) [0x574f07efc7e9]
#4 ./test(main+0x12) [0x574f07efc802]
#5 /usr/lib/libc.so.6(+0x25e08) [0x76954694fe08]
#6 /usr/lib/libc.so.6(__libc_start_main+0x8c) [0x76954694fecc]
#7 ./test(_start+0x25) [0x574f07efc6c5]
```
test program is:
```
function testfun2() result(err)
implicit none
integer :: err
err = 1
call backtrace
end function testfun2
subroutine testfun1()
implicit none
integer :: err
integer :: testfun2
err = testfun2()
end subroutine testfun1
program test_backtrace
call testfun1()
end program test_backtrace
```
I am well aware of the importance of line numbers, so I am now working
on implementing line numbers (by parsing DWARF information) and
supporting cross-platform (Windows) support.
According to the C99 standard, <fenv.h> may not define FE_INVALID and
the likes. Even if C++11 mandate them, musl and emscripten don't provide
them, so handle that case.
The semantic checks and runtime have been supported. This supports the
lowering of intrinsic ABORT.
`gfortran` prints a backtrace before abort, unless `-fno-backtrace` is
given. This is good to use. The intrinsic BACKTRACE is not supported
yet, so add TODO in the runtime.
This extention is needed in SPEC2017 521.wrf_r in
https://github.com/llvm/llvm-project/issues/55955.
Reviewed By: klausler
Differential Revision: https://reviews.llvm.org/D130439
As per Steve Scalpone's suggestion, I've renamed the runtime routine to
better evoke its purpose.
I implemented a routine called "Crash" and added a test.
Differential Revision: https://reviews.llvm.org/D118703
In 'STOP bye bye', do not print 'Fortran STOP:` before 'bye bye' when
NO_STOP_MESSAGE environment variable is set at runtime.
Also only exit with code 1 in StopStatementText if this is an ERROR STOP.
This matches other compiler behaviors.
Move STOP related unit tests in their own test file and add new tests to
cover this change.
Differential Revision: https://reviews.llvm.org/D114152
When an environment variable NO_STOP_MESSAGE=1 is set,
assume that STOP statements with a successful code
have QUIET=.TRUE.
Differential Revision: https://reviews.llvm.org/D113701
Support the extension intrinsic subroutines EXIT([status]) and ABORT()
in the intrinsic table and runtime support library. Lowering remains
to be done.
Differential Revision: https://reviews.llvm.org/D110741
Move the closure of the subset of flang/runtime/*.h header files that
are referenced by source files outside flang/runtime (apart from unit tests)
into a new directory (flang/include/flang/Runtime) so that relative
include paths into ../runtime need not be used.
flang/runtime/pgmath.h.inc is moved to flang/include/flang/Evaluate;
it's not used by the runtime.
Differential Revision: https://reviews.llvm.org/D109107
Support integer and default character stop codes on PAUSE
statements. Add length argument to STOP statement with a
character stop code.
Differential revision: https://reviews.llvm.org/D88692
Add a missing newline to IEEE FP flag formatting, and
don't neglect to emit STOP when there's no code number.
Reviewed By: tskeith
Differential Revision: https://reviews.llvm.org/D84060
Complete the rework of the initial implementation of external I/O
to fix problems found in testing (tests to follow); add handlers
for hitherto unimplemented PAUSE, FLUSH, ENDFILE, BACKSPACE, and
REWIND statements.
Reviewed By: tskeith, sscalpone
Differential Revision: https://reviews.llvm.org/D83162
Use internal units for internal I/O state
Replace use of virtual functions
reference_wrapper
Internal formatted output to array descriptor
Delete dead code
Begin list-directed internal output
Refactorings and renamings for clarity
List-directed external I/O (character)
COMPLEX list-directed output
Control list items
First cut at unformatted I/O
More OPEN statement work; rename class to ExternalFileUnit
Complete OPEN (exc. for POSITION=), add CLOSE()
OPEN(POSITION=)
Flush buffers on crash and for terminal output; clean up
Documentation
Fix backquote in documentation
Fix typo in comment
Begin implementation of input
Refactor binary floating-point properties to a new header, simplify numeric output editing
Dodge spurious GCC 7.2 build warning
Address review comments
Original-commit: flang-compiler/f18@9c4bba11cf
Reviewed-on: https://github.com/flang-compiler/f18/pull/982
Address review comments
Integer output data editing (I,B,O,Z)
Full integer output formatting
Stub out some work in progress
Progress on E output data editing
E, D, EN, and ES output editing done
Fw.d output editing
Real G output editing
G output editing for reals
Make environment a distinct module
CHARACTER and LOGICAL output editing
Minimal decimal representations for E0, F0, G0 editing
Move real output editing code into its own file
Fix/dodge some GCC build problems
Prep work for external I/O statement state
External HELLO, WORLD
Fix build problem with GCC
Add virtual destructors where needed
Add new test
Original-commit: flang-compiler/f18@c3f1774f8e
Reviewed-on: https://github.com/flang-compiler/f18/pull/950
Updated CMake files accordingly, using better regex
Updated license headers to match new extension and fit within 80 columns
Updated other comments within files that referred to the old extension
Original-commit: flang-compiler/f18@ae7721e611
Reviewed-on: https://github.com/flang-compiler/f18/pull/958
