This PR adds debug support for common block in flang. As variable which
are part of a common block don't have a special marker to recognize
them, we use the following check to find them.
%0 = fir.address_of(@a)
%1 = fir.convert %0
%2 = fir.coordinate_of %1, %c0
%3 = fir.convert %2
%4 = fircg.ext_declare %3
If the memref of a fircg.ext_declare points to a fir.coordinate_of and
that in turn points to an fir.address_of (ignoring immediate
fir.convert) then we assume that it is a common block variable. The
fir.address_of gives us the global symbol which is the storage for
common block and fir.coordinate_of provides the offset in this storage.
The debug hierarchy looks like as
subroutine f3
integer :: x, y
common /a/ x, y
end subroutine
@a_ = global { ... } { ... }, !dbg !26, !dbg !28!23 = !DISubprogram(name: "f3"...)
!24 = !DICommonBlock(scope: !23, name: "a", ...)
!25 = !DIGlobalVariable(name: "x", scope: !24 ...)
!26 = !DIGlobalVariableExpression(var: !25, expr: !DIExpression())
!27 = !DIGlobalVariable(name: "y", scope: !24 ...)
!28 = !DIGlobalVariableExpression(var: !27, expr:
!DIExpression(DW_OP_plus_uconst, 4))
This required following changes:
1. Instead of using DIGlobalVariableAttr in the FusedLoc of GlobalOp, we
use DIGlobalVariableExpressionAttr. This allows us the generate the
DIExpression where we have the information.
2. Previously, only one DIGlobalVariableExpressionAttr could be linked
to one global op. I recently removed this restriction in mlir. To make
use of it, we add an ArrayAttr to the FusedLoc of a GlobalOp. This
allows us to pass multiple DIGlobalVariableExpressionAttr.
3. I was depending on the name of global for the name of the common
block. The name gets a '_' appended. I could not find a utility function
in flang to remove it so I have to brute force it.
This PR generates dwarf to extract the information about the arrays from
descriptor. The DWARF needs the offset of the fields like `lower_bound`
and `extent`. The getComponentOffset has been added to calculate
them which pushes the issue of host and target data size into
getDescFieldTypeModel.
As we use data layout now, some tests needed to be adjusted to have a
dummy data layout to avoid failure.
With this change in place, GDB is able show the assumed shape arrays
correctly.
subroutine ff(n, m, arr)
integer n, m
integer :: arr(:, :)
print *, arr
do i = 1, n
do j = 1, m
arr(j, i) = (i * 5) + j + 10
end do
end do
print *, arr
end subroutine ff
Breakpoint 1, ff (n=4, m=3, arr=...) at test1.f90:13
13 print *, arr
(gdb) p arr
$1 = ((6, 7, 8, 9) (11, 12, 13, 14) (16, 17, 18, 19))
(gdb) ptype arr
type = integer (4,3)
(gdb) c
Continuing.
6 7 8 9 11 12 13 14 16 17 18 19
This PR add debug info for module variables. The module variables are
added as global variables but their scope is set to module instead of
compile unit. The scope of function declared inside a module is also set
accordingly.
After this patch, a module variable could be evaluated in the GDB as `p
helper::gli` where helper is name of the module and gli is the name of
the variable. A future patch will add the import module functionality
which will remove the need to prefix the name with helper::.
The line number where is module is declared is a best guess at the
moment as this information is not part of the GlobalOp.
