gdb/fortran: Fix printing of logical true values for Flang

GDB is not able to print logical true values for Flang compiler.

Actual result:

  (gdb) p l
  $1 = 4294967295

Expected result:

  (gdb) p l
  $1 = .TRUE.

This is due to GDB expecting representation of true value being 1.
The Fortran standard doesnt specify how LOGICAL types are represented.
Different compilers use different non-zero values to represent logical
true. The gfortran compiler uses 1 to represent logical true and the
flang compiler uses -1. GDB should accept all the non-zero values as
true.

This is achieved by handling TYPE_CODE_BOOL in f_val_print and
printing any non-zero value as true.

gdb/ChangeLog:

	* f-valprint.c (f_val_print): Handle TYPE_CODE_BOOL, any non-zero
	value should be printed as true.

gdb/testsuite/ChangeLog:

	* gdb.fortran/logical.exp: Add tests that any non-zero value is
	printed as true.

1 files changed, 18 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.fortran/logical.exp b/gdb/testsuite/gdb.fortran/logical.exp
index f002815..96e6f8f 100644
--- a/gdb/testsuite/gdb.fortran/logical.exp
+++ b/gdb/testsuite/gdb.fortran/logical.exp
@@ -33,3 +33,21 @@ gdb_test "p l1" " = \\.TRUE\\."
 gdb_test "p l2" " = \\.TRUE\\."
 gdb_test "p l4" " = \\.TRUE\\."
 gdb_test "p l8" " = \\.TRUE\\."
+
+# Different Fortran compilers use different values for logical true.
+# Check how GDB handles this by modifying the underlying value for our
+# logical variables and check they still print as true.
+foreach_with_prefix var { l l1 l2 l4 l8 } {
+    set len [get_integer_valueof "sizeof (${var})" "get sizeof ${var}"]
+    set addr [get_hexadecimal_valueof "&l" "get address of ${var}"]
+
+    for { set i 0 } { $i < $len } { incr i } {
+	with_test_prefix "byte $i" {
+	    gdb_test_no_output "set *((uint8_t *) ${addr}) = 0xff" \
+		"set contents of byte at offset $i"
+	    gdb_test "p l" " = \\.TRUE\\."
+	    incr addr
+	    set addr [format "0x%x" $addr]
+	}
+    }
+}