Fortran: Add range-based diagnostic

GCC's diagnostic engine gained a while ago support for ranges, i.e. instead
of pointing at a single character '^', it can also have a '~~~~^~~~~~' range.

This patch adds support for this and adds 9 users for it, which covers the
most common cases. A single '^' can be still useful. Some location data in
gfortran is rather bad - often the matching pattern includes whitespace such
that the before or after location points to the beginning/end of the
whitespace, which can be far of especially when comments and/or continuation
lines are involed. Otherwise, often a '^' still sufficient, albeit wrong
location data only becomes obvious once starting to use ranges.

The 'locus' is extended to support two ways to store the data; hereby
gfc_current_locus always contains the old format (at least during parsing)
and gfc_current_locus shall not be used in trans*.cc. The latter permits
a nice cleanup to just use input_location. Otherwise, the new format is
only used when switching to ranges.
The only reason to convert from location_t to locus occurs in trans*.cc
for the gfc_error (etc.) diagnostic and for gfc_trans_runtime_check; there
are 5 currently 5 such cases.  For gfc_* diagnostic, we could think of
another letter besides %L or a modifier like '%lL', if deemed useful.

In any case, the new format is just:
  locus->u.location = linemap_position_for_loc_and_offset (line_table,
                         loc->u.lb->location, loc->nextc - loc->u.lb->line);
  locus->nextc = (gfc_char_t *) -1;  /* Marker for new format. */
i.e. using the existing location_t location in in the linebuffer (which
points to column 0) and add as offset the actually used column number.

As location_t handles ranges, we just use it also to store them via:
  location = make_location (caret, begin, end)
There are a few convenience macros/functions but that's all.

Alongside, a few minor fixes were done: linemap_location_before_p replaces
a line-number based comparison, which does not handle multiple statements
in the same line that ';' allows for.

gcc/fortran/ChangeLog:

	* data.cc (gfc_assign_data_value): Use linemap_location_before_p
	and GFC_LOCUS_IS_SET.
	* decl.cc (gfc_verify_c_interop_param): Make better translatable.
	(build_sym, variable_decl, gfc_match_formal_arglist,
	gfc_match_subroutine): Add range-based locations, use it in
	diagnostic and gobble whitespace for better locations.
	* error.cc (gfc_get_location_with_offset): Handle new format.
	(gfc_get_location_range): New.
	* expr.cc (gfc_check_assign): Use GFC_LOCUS_IS_SET.
	* frontend-passes.cc (check_locus_code, check_locus_expr):
	Likewise.
	(runtime_error_ne): Use GFC_LOCUS_IS_SET.
	* gfortran.h (locus): Change lb to union with lb and location.
	(GFC_LOCUS_IS_SET): Define.
	(gfc_get_location_range): New prototype.
	(gfc_new_symbol, gfc_get_symbol, gfc_get_sym_tree,
	gfc_get_ha_symbol, gfc_get_ha_sym_tree): Take optional locus
	argument.
	* io.cc (io_constraint): Use GFC_LOCUS_IS_SET.
	* match.cc (gfc_match_sym_tree): Use range locus.
	* openmp.cc (gfc_match_omp_variable_list,
	gfc_match_omp_doacross_sink): Likewise.
	* parse.cc (next_free): Update for locus struct change.
	* primary.cc (gfc_match_varspec): Likewise.
	(match_variable): Use range locus.
	* resolve.cc (find_array_spec): Use GFC_LOCUS_IS_SET.
	* scanner.cc (gfc_at_eof, gfc_at_bol, gfc_start_source_files,
	gfc_advance_line, gfc_define_undef_line, skip_fixed_comments,
	gfc_gobble_whitespace, include_stmt, gfc_new_file): Update
	for locus struct change.
	* symbol.cc (gfc_new_symbol, gfc_get_sym_tree, gfc_get_symbol,
	gfc_get_ha_sym_tree, gfc_get_ha_symbol): Take optional locus.
	* trans-array.cc (gfc_trans_array_constructor_value): Use %L not %C.
	(gfc_trans_g77_array, gfc_trans_dummy_array_bias,
	gfc_trans_class_array, gfc_trans_deferred_array): Replace
	gfc_{save,set,restore}_backend_locus by directly using
	input_location.
	* trans-common.cc (build_equiv_decl, get_init_field): Likewise.
	* trans-decl.cc (gfc_get_extern_function_decl, build_function_decl,
	build_entry_thunks, gfc_null_and_pass_deferred_len,
	gfc_trans_deferred_vars, gfc_trans_use_stmts, finish_oacc_declare,
	gfc_generate_block_data): Likewise.
	* trans-expr.cc (gfc_copy_class_to_class, gfc_conv_expr): Changes
	to avoid gfc_current_locus.
	* trans-io.cc (set_error_locus): Likewise.
	* trans-openmp.cc (gfc_trans_omp_workshare): Use input_locus directly.
	* trans-stmt.cc (gfc_trans_if_1): Likewise and use GFC_LOCUS_IS_SET.
	* trans-types.cc (gfc_get_union_type, gfc_get_derived_type): Likewise.
	* trans.cc (gfc_locus_from_location): New.
	(trans_runtime_error_vararg, gfc_trans_runtime_check): Use location_t
	for file + line data.
	(gfc_current_backend_file, gfc_save_backend_locus,
	gfc_set_backend_locus, gfc_restore_backend_locus): Remove.
	(trans_code): Use input_location directly, don't set gfc_current_locus.
	* trans.h (gfc_save_backend_locus, gfc_set_backend_locus,
	gfc_restore_backend_locus): Remove prototypes.
	(gfc_locus_from_location): Add prototype.

gcc/testsuite/ChangeLog:

	* gfortran.dg/bounds_check_25.f90: Update expected column
	in the diagnostic.
	* gfortran.dg/goacc/pr92793-1.f90: Likewise.
	* gfortran.dg/gomp/allocate-14.f90: Likewise.
	* gfortran.dg/gomp/polymorphic-mapping.f90: Likewise.
	* gfortran.dg/gomp/reduction5.f90: Likewise.
	* gfortran.dg/gomp/reduction6.f90: Likewise.

6 files changed, 26 insertions, 26 deletions

diff --git a/gcc/testsuite/gfortran.dg/bounds_check_25.f90 b/gcc/testsuite/gfortran.dg/bounds_check_25.f90
index cc22475..c55a102 100644
--- a/gcc/testsuite/gfortran.dg/bounds_check_25.f90
+++ b/gcc/testsuite/gfortran.dg/bounds_check_25.f90
@@ -25,8 +25,8 @@ contains
   end subroutine bla
 end
 
-! { dg-final { scan-tree-dump-times "line 15 .* bound mismatch for dimension 1 of array .'.*.'" 1 "original" } }
-! { dg-final { scan-tree-dump-times "line 15 .* bound mismatch for dimension 2 of array .'.*.'" 1 "original" } }
+! { dg-final { scan-tree-dump-times "around line 15.* bound mismatch for dimension 1 of array .'.*.'" 1 "original" } }
+! { dg-final { scan-tree-dump-times "around line 15.* bound mismatch for dimension 2 of array .'.*.'" 1 "original" } }
 
-! { dg-final { scan-tree-dump-times "line 24 .* bound mismatch for dimension 1 of array .'d%%m.'" 1 "original" } }
-! { dg-final { scan-tree-dump-times "line 24 .* bound mismatch for dimension 2 of array .'d%%m.'" 1 "original" } }
+! { dg-final { scan-tree-dump-times "At line 24 .* bound mismatch for dimension 1 of array .'d%%m.'" 1 "original" } }
+! { dg-final { scan-tree-dump-times "At line 24 .* bound mismatch for dimension 2 of array .'d%%m.'" 1 "original" } }
diff --git a/gcc/testsuite/gfortran.dg/goacc/pr92793-1.f90 b/gcc/testsuite/gfortran.dg/goacc/pr92793-1.f90
index 422131b..7a33d7f 100644
--- a/gcc/testsuite/gfortran.dg/goacc/pr92793-1.f90
+++ b/gcc/testsuite/gfortran.dg/goacc/pr92793-1.f90
@@ -21,8 +21,8 @@ subroutine check ()
       !$acc  &   & ! { dg-final { scan-tree-dump-times "pr92793-1\\\.f90:26:22\\\] #pragma acc loop" 1 "original" } }
      !$acc &     & ! { dg-final { scan-tree-dump-times "pr92793-1\\\.f90:26:22\\\] #pragma acc loop" 1 "gimple" } }
     !$acc&       reduction  ( +    : sum ) & ! { dg-line sum1 }
- !$acc && ! Fortran location information points to the ':' in 'reduction(+:sum)'.
-   !$acc   &    &  ! { dg-message "36: location of the previous reduction for 'sum'" "" { target *-*-* } sum1 }
+ !$acc && ! Fortran location information points to the 's' in 'reduction(+:sum)'.
+   !$acc   &    &  ! { dg-message "38: location of the previous reduction for 'sum'" "" { target *-*-* } sum1 }
 !$acc&     independent
   do i = 1, 10
       !$acc loop &
@@ -32,7 +32,7 @@ subroutine check ()
   !$acc & reduction(-: diff     ) &
              !$acc&reduction(- :    sum) & ! { dg-line sum2 }
             !$acc & & ! Fortran location information points to the ':' in 'reduction(-:sum)'.
-          !$acc& & ! { dg-warning "32: conflicting reduction operations for 'sum'" "" { target *-*-* } sum2 }
+          !$acc& & ! { dg-warning "37: conflicting reduction operations for 'sum'" "" { target *-*-* } sum2 }
           !$acc       &independent
      do j = 1, 10
            sum &
@@ -107,7 +107,7 @@ subroutine gwv_s_l ()
 !$acc end serial
 end subroutine gwv_s_l
 
-subroutine gwv_r () ! { dg-message "16: enclosing routine" }
+subroutine gwv_r () ! { dg-message "1: enclosing routine" }
   implicit none (type, external)
   integer :: i, j, k
 
diff --git a/gcc/testsuite/gfortran.dg/gomp/allocate-14.f90 b/gcc/testsuite/gfortran.dg/gomp/allocate-14.f90
index 4fed192..4db950f 100644
--- a/gcc/testsuite/gfortran.dg/gomp/allocate-14.f90
+++ b/gcc/testsuite/gfortran.dg/gomp/allocate-14.f90
@@ -32,10 +32,10 @@ subroutine coarrays(x)
 
   !$omp allocate(x)  ! { dg-error "Unexpected dummy argument 'x' as argument at .1. to declarative !.OMP ALLOCATE" }
 
-  !$omp allocators allocate(y) ! { dg-error "28:Unexpected coarray 'y' in 'allocate' at .1." }
+  !$omp allocators allocate(y) ! { dg-error "29:Unexpected coarray 'y' in 'allocate' at .1." }
     allocate(y[*])
 
-  !$omp allocate(z) ! { dg-error "17:Unexpected coarray 'z' in 'allocate' at .1." }
+  !$omp allocate(z) ! { dg-error "18:Unexpected coarray 'z' in 'allocate' at .1." }
     allocate(z(5)[*])
   x = 5
 end 
diff --git a/gcc/testsuite/gfortran.dg/gomp/polymorphic-mapping.f90 b/gcc/testsuite/gfortran.dg/gomp/polymorphic-mapping.f90
index dc3eb9e..dd7eb31 100644
--- a/gcc/testsuite/gfortran.dg/gomp/polymorphic-mapping.f90
+++ b/gcc/testsuite/gfortran.dg/gomp/polymorphic-mapping.f90
@@ -11,17 +11,17 @@ pa => ca
 !        11111111112222222222333333333344
 !2345678901234567890123456789012345678901
 !$omp target enter data map(c, ca, p, pa)
-! { dg-warning "28:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-1 }
-! { dg-warning "30:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-2 }
-! { dg-warning "34:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-3 }
-! { dg-warning "37:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-4 }
+! { dg-warning "29:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-1 }
+! { dg-warning "32:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-2 }
+! { dg-warning "36:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-3 }
+! { dg-warning "39:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-4 }
 
 !        11111111112222222222333333333344
 !2345678901234567890123456789012345678901
-!$omp target firstprivate(ca)  ! { dg-warning "26:FIRSTPRIVATE with polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" }
+!$omp target firstprivate(ca)  ! { dg-warning "27:FIRSTPRIVATE with polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" }
 !$omp end target
 
-!$omp target parallel do firstprivate(ca)  ! { dg-warning "38:FIRSTPRIVATE with polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" }
+!$omp target parallel do firstprivate(ca)  ! { dg-warning "39:FIRSTPRIVATE with polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" }
 do x = 0, 5
 end do
 
@@ -36,14 +36,14 @@ end block
 !        11111111112222222222333333333344
 !2345678901234567890123456789012345678901
 !$omp target update from(c,ca), to(p,pa)
-! { dg-warning "25:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-1 }
-! { dg-warning "27:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-2 }
-! { dg-warning "35:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-3 }
-! { dg-warning "37:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-4 }
+! { dg-warning "26:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-1 }
+! { dg-warning "28:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-2 }
+! { dg-warning "36:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-3 }
+! { dg-warning "38:Mapping polymorphic list item at .1. is unspecified behavior \\\[-Wopenmp\\\]" "" { target *-*-* } .-4 }
 
 ! -------------------------
 
-!$omp target parallel map(release: x) ! { dg-error "35:TARGET with map-type other than TO, FROM, TOFROM, or ALLOC on MAP clause" }
+!$omp target parallel map(release: x) ! { dg-error "36:TARGET with map-type other than TO, FROM, TOFROM, or ALLOC on MAP clause" }
 
 block
 end block
diff --git a/gcc/testsuite/gfortran.dg/gomp/reduction5.f90 b/gcc/testsuite/gfortran.dg/gomp/reduction5.f90
index 85491f0..b4b1c46 100644
--- a/gcc/testsuite/gfortran.dg/gomp/reduction5.f90
+++ b/gcc/testsuite/gfortran.dg/gomp/reduction5.f90
@@ -21,13 +21,13 @@ end do
 !$omp end task  ! { dg-error "Unexpected !.OMP END TASK statement" }
 
 !$omp taskloop reduction(inscan,+:a) in_reduction(+:b) ! { dg-error "'inscan' REDUCTION clause on construct other than DO, SIMD, DO SIMD, PARALLEL DO, PARALLEL DO SIMD" }
-  ! { dg-error "34: With INSCAN at .1., expected loop body with ..OMP SCAN between two structured block sequences" "" { target *-*-* } .-1 }
+  ! { dg-error "35: With INSCAN at .1., expected loop body with ..OMP SCAN between two structured block sequences" "" { target *-*-* } .-1 }
   ! { dg-error "'inscan' and non-'inscan' 'reduction' clauses on the same construct" "" { target *-*-* } .-2 }
 do i=1,10
   a = a + 1
 end do
 
-!$omp taskloop reduction(task,+:a) in_reduction(+:b) ! { dg-error "32: Only DEFAULT permitted as reduction-modifier in REDUCTION clause" }
+!$omp taskloop reduction(task,+:a) in_reduction(+:b) ! { dg-error "33: Only DEFAULT permitted as reduction-modifier in REDUCTION clause" }
 do i=1,10
   a = a + 1
 end do
@@ -36,7 +36,7 @@ end do
   a = a + 1
 !$omp end teams
 
-!$omp teams reduction(task, +:b) ! { dg-error "30: Only DEFAULT permitted as reduction-modifier in REDUCTION clause" }
+!$omp teams reduction(task, +:b) ! { dg-error "31: Only DEFAULT permitted as reduction-modifier in REDUCTION clause" }
   a = a + 1
 !$omp end teams
 
diff --git a/gcc/testsuite/gfortran.dg/gomp/reduction6.f90 b/gcc/testsuite/gfortran.dg/gomp/reduction6.f90
index 321f096..f6d95af 100644
--- a/gcc/testsuite/gfortran.dg/gomp/reduction6.f90
+++ b/gcc/testsuite/gfortran.dg/gomp/reduction6.f90
@@ -4,13 +4,13 @@ implicit none
 integer :: a, b, i
 a = 0
 
-!$omp simd reduction(inscan,+:a)  ! { dg-error "30: With INSCAN at .1., expected loop body with ..OMP SCAN between two structured block sequences" }
+!$omp simd reduction(inscan,+:a)  ! { dg-error "31: With INSCAN at .1., expected loop body with ..OMP SCAN between two structured block sequences" }
 do i=1,10
   a = a + 1
 end do
 
 !$omp parallel
-!$omp do reduction(inscan,+:a)  ! { dg-error "28: With INSCAN at .1., expected loop body with ..OMP SCAN between two structured block sequences" }
+!$omp do reduction(inscan,+:a)  ! { dg-error "29: With INSCAN at .1., expected loop body with ..OMP SCAN between two structured block sequences" }
 do i=1,10
   a = a + 1
 end do