[RFA] gdb/13483

[Keith Seitz <keiths at redhat dot com>]

Hi,

The bug in $SUBJECT talks about changing gdb to allow certain 
conversions to boolean during function calls.

The attached patch changes rank_one_type to fully implement the C++ 
standard [as of n3290 draft] for boolean conversions (section 4.12.1, 
conv.bool). I've re-purposed the BOOL_PTR_CONVERSION_BADNESS and changed 
that to a more generic BOOL_CONVERSION_BADNESS which includes all of 
these cases.

[No regressions on x86_64 native and native-gdbserver.]

Comments/questions/concerns?
Keith

ChangeLog
2012-08-31  Keith Seitz  <keiths@redhat.com>

	PR gdb/13483
	* gdbtypes.h (BOOL_PTR_CONVERSION_BADNESS): Rename to ...
	(BOOL_CONVERSION_BADNESS): ... this.
	* gdbtypes.c (BOOL_PTR_CONVERSION_BADNESS): Likewise.
	(rank_one_type): Allow all boolean conversions
	permitted by the standard.

testsuite/ChangeLog
2012-08-31  Keith Seitz  <keiths@redhat.com>

	PR gdb/13483
	* gdb.cp/converts.cc (A::A): Add ctor.
	(A::member_): Add member.
	(enum my_enum): New enumeration.
	(main): Add calls to foo1_7 with various
	permitted arguments.
	* gdb.cp/converts.exp: Add tests for boolean
	conversions permitted by the standard.

diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index 991026b..73fcbb1 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -1603,8 +1603,8 @@ extern const struct rank FLOAT_CONVERSION_BADNESS;
 extern const struct rank INT_FLOAT_CONVERSION_BADNESS;
 /* Badness of conversion of pointer to void pointer.  */
 extern const struct rank VOID_PTR_CONVERSION_BADNESS;
-/* Badness of conversion of pointer to boolean.  */
-extern const struct rank BOOL_PTR_CONVERSION_BADNESS;
+/* Badness of conversion to boolean.  */
+extern const struct rank BOOL_CONVERSION_BADNESS;
 /* Badness of converting derived to base class.  */
 extern const struct rank BASE_CONVERSION_BADNESS;
 /* Badness of converting from non-reference to reference.  */
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 21d9043..8ac8799 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -54,7 +54,7 @@ const struct rank INTEGER_CONVERSION_BADNESS = {2,0};
 const struct rank FLOAT_CONVERSION_BADNESS = {2,0};
 const struct rank INT_FLOAT_CONVERSION_BADNESS = {2,0};
 const struct rank VOID_PTR_CONVERSION_BADNESS = {2,0};
-const struct rank BOOL_PTR_CONVERSION_BADNESS = {3,0};
+const struct rank BOOL_CONVERSION_BADNESS = {3,0};
 const struct rank BASE_CONVERSION_BADNESS = {2,0};
 const struct rank REFERENCE_CONVERSION_BADNESS = {2,0};
 const struct rank NULL_POINTER_CONVERSION_BADNESS = {2,0};
@@ -2718,14 +2718,23 @@ rank_one_type (struct type *parm, struct type *arg, struct value *value)
     case TYPE_CODE_BOOL:
       switch (TYPE_CODE (arg))
 	{
+	  /* n3290 draft, section 4.12.1 (conv.bool):
+
+	     "A prvalue of arithmetic, unscoped enumeration, pointer, or
+	     pointer to member type can be converted to a prvalue of type
+	     bool.  A zero value, null pointer value, or null member pointer
+	     value is converted to false; any other value is converted to
+	     true.  A prvalue of type std::nullptr_t can be converted to a
+	     prvalue of type bool; the resulting value is false."  */
 	case TYPE_CODE_INT:
 	case TYPE_CODE_CHAR:
-	case TYPE_CODE_RANGE:
 	case TYPE_CODE_ENUM:
 	case TYPE_CODE_FLT:
-	  return INCOMPATIBLE_TYPE_BADNESS;
+	case TYPE_CODE_MEMBERPTR:
 	case TYPE_CODE_PTR:
-	  return BOOL_PTR_CONVERSION_BADNESS;
+	  return BOOL_CONVERSION_BADNESS;
+	case TYPE_CODE_RANGE:
+	  return INCOMPATIBLE_TYPE_BADNESS;
 	case TYPE_CODE_BOOL:
 	  return EXACT_MATCH_BADNESS;
 	default:
diff --git a/gdb/testsuite/gdb.cp/converts.cc b/gdb/testsuite/gdb.cp/converts.cc
index ecebbf8..1cda43d 100644
--- a/gdb/testsuite/gdb.cp/converts.cc
+++ b/gdb/testsuite/gdb.cp/converts.cc
@@ -1,10 +1,17 @@
-class A {};
+class A
+{
+public:
+  A() : member_ (0) {};
+  int member_;
+};
 class B : public A {};
 
 typedef A TA1;
 typedef A TA2;
 typedef TA2 TA3;
 
+enum my_enum {MY_A, MY_B, MY_C, MY_D};
+
 int foo0_1 (TA1)  { return 1; }
 int foo0_2 (TA3)  { return 2; }
 int foo0_3 (A***) { return 3; }
@@ -62,6 +69,21 @@ int main()
   foo2_3 (b);        // ..array of pointers
   foo2_4 ((int**)b); // ..array of wrong pointers
 
+  // X to boolean conversions allowed by the standard
+  int integer = 0;
+  long long_int = 1;
+  float fp = 1.0;
+  double dp = 1.0;
+  foo1_7 (integer);		// integer to boolean
+  foo1_7 (long_int);		// long to boolean
+  foo1_7 (*a);			// char to boolean
+  foo1_7 (MY_A);		// unscoped enum to boolean
+  foo1_7 (&foo1_7);		// pointer to boolean
+  foo1_7 (&A::member_);		// pointer to member to boolean
+  foo1_7 (a);			// pointer to boolean
+  foo1_7 (fp);			// float to boolean
+  foo1_7 (dp);			// double  to boolean
+
   foo3_1 (0, 0);
   foo3_2 (0, static_cast<char const**> (0));
   foo3_2 (0, 0);
diff --git a/gdb/testsuite/gdb.cp/converts.exp b/gdb/testsuite/gdb.cp/converts.exp
index 414e2d0..148ac0f 100644
--- a/gdb/testsuite/gdb.cp/converts.exp
+++ b/gdb/testsuite/gdb.cp/converts.exp
@@ -77,6 +77,21 @@ gdb_test "p foo3_1 (0, (const char**) 1)" " = 31"
 gdb_test "p foo3_2 (0, 0)" "= 32"
 gdb_test "p foo3_2 (0, (char const**) 0)" " = 320"
 
+# Tests for boolean conversions allowed by the standard
+gdb_test "p foo1_7(0)" " = 17"
+gdb_test "p foo1_7(integer)" " = 17"
+gdb_test "p foo1_7(long_int)" " = 17"
+gdb_test "p foo1_7(*a)" " = 17"
+gdb_test "p foo1_7(MY_A)" " = 17"
+gdb_test "p foo1_7(&foo1_7)" " = 17"
+gdb_test "p foo1_7(&A::member_)" " = 17"
+gdb_test "p foo1_7(a)" " = 17"
+gdb_test "p foo1_7(fp)" " = 17"
+gdb_test "p foo1_7(dp)" " = 17"
+gdb_test "p foo1_7(-1.23)" " = 17"
+gdb_test "p foo1_7(ta)" \
+    "Cannot resolve function foo1_7 to any overloaded instance"
+
 # Test for strict type checking
 set error_str "Cannot resolve function %s to any overloaded instance"
 gdb_test "show check type" "Strict type checking is on\."