[PATCH v2] guile: fix make-value with pointer type

[PATCH v2] guile: fix make-value with pointer type

[George Barrett]

Calling the `make-value' procedure with an integer value and a pointer
type for the #:type argument triggers a failed assertion in
`get_unsigned_type_max', as that function doesn't consider pointers to
be an unsigned type. This commit fixes the issue by adding a separate
code path for pointers.

As previously suggested, range checking is done using a new helper
function in gdbtypes.

gdb/ChangeLog:

2021-06-07  George Barrett  <bob@bob131.so>

	* gdbtypes.h (get_pointer_type_max): Add declaration.
	* gdbtypes.c (get_pointer_type_max): Add definition for new
	helper function.
	* guile/scm-math.c (vlscm_convert_typed_number): Add code path
	for handling conversions to pointer types without failing an
	assert.

gdb/testsuite/ChangeLog:

2021-06-07  George Barrett  <bob@bob131.so>

	* gdb.guile/scm-math.exp (test_value_numeric_ops): Add test
	for creating pointers with make-value.
	(test_make_pointer_value, test_pointer_numeric_range): Add
	test procedures containing checks for integer-to-pointer
	validation.
---
 gdb/gdbtypes.c                       | 16 +++++++++++
 gdb/gdbtypes.h                       |  2 ++
 gdb/guile/scm-math.c                 | 18 +++++++++++--
 gdb/testsuite/gdb.guile/scm-math.exp | 40 ++++++++++++++++++++++++++++
 4 files changed, 74 insertions(+), 2 deletions(-)

diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 84c4f34cf30..6e74cabc3b3 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -1931,6 +1931,22 @@ get_signed_type_minmax (struct type *type, LONGEST *min, LONGEST *max)
   *max = ((ULONGEST) 1 << (n - 1)) - 1;
 }
 
+/* Store in *MAX the largest value representable by pointer type
+   TYPE. */
+
+void
+get_pointer_type_max (struct type *type, CORE_ADDR *max)
+{
+  unsigned int n;
+
+  type = check_typedef (type);
+  gdb_assert (type->code () == TYPE_CODE_PTR);
+  gdb_assert (TYPE_LENGTH (type) <= sizeof (CORE_ADDR));
+
+  n = TYPE_LENGTH (type) * TARGET_CHAR_BIT;
+  *max = ((((CORE_ADDR) 1 << (n - 1)) - 1) << 1) | 1;
+}
+
 /* Internal routine called by TYPE_VPTR_FIELDNO to return the value of
    cplus_stuff.vptr_fieldno.
 
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index bb4d26eef1a..054a7096f0a 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -2499,6 +2499,8 @@ extern void get_unsigned_type_max (struct type *, ULONGEST *);
 
 extern void get_signed_type_minmax (struct type *, LONGEST *, LONGEST *);
 
+extern void get_pointer_type_max (struct type *, CORE_ADDR *);
+
 /* * Resolve all dynamic values of a type e.g. array bounds to static values.
    ADDR specifies the location of the variable the type is bound to.
    If TYPE has no dynamic properties return TYPE; otherwise a new type with
diff --git a/gdb/guile/scm-math.c b/gdb/guile/scm-math.c
index d9fd6718196..84de21cb440 100644
--- a/gdb/guile/scm-math.c
+++ b/gdb/guile/scm-math.c
@@ -524,8 +524,7 @@ vlscm_convert_typed_number (const char *func_name, int obj_arg_pos, SCM obj,
 			    int type_arg_pos, SCM type_scm, struct type *type,
 			    struct gdbarch *gdbarch, SCM *except_scmp)
 {
-  if (is_integral_type (type)
-      || type->code () == TYPE_CODE_PTR)
+  if (is_integral_type (type))
     {
       if (type->is_unsigned ())
 	{
@@ -558,6 +557,21 @@ vlscm_convert_typed_number (const char *func_name, int obj_arg_pos, SCM obj,
 	  return value_from_longest (type, gdbscm_scm_to_longest (obj));
 	}
     }
+  else if (type->code () == TYPE_CODE_PTR)
+    {
+      CORE_ADDR max;
+
+      get_pointer_type_max (type, &max);
+      if (!scm_is_unsigned_integer (obj, 0, max))
+	{
+	  *except_scmp
+	    = gdbscm_make_out_of_range_error (func_name,
+					      obj_arg_pos, obj,
+					_("value out of range for type"));
+	  return NULL;
+	}
+      return value_from_pointer (type, gdbscm_scm_to_ulongest (obj));
+    }
   else if (type->code () == TYPE_CODE_FLT)
     return value_from_host_double (type, scm_to_double (obj));
   else
diff --git a/gdb/testsuite/gdb.guile/scm-math.exp b/gdb/testsuite/gdb.guile/scm-math.exp
index ba975454ce5..ee428e5cc90 100644
--- a/gdb/testsuite/gdb.guile/scm-math.exp
+++ b/gdb/testsuite/gdb.guile/scm-math.exp
@@ -137,6 +137,15 @@ proc test_value_numeric_ops {} {
     gdb_test "gu (print (value-sub b a))" \
 	"= 3" "subtract two pointer values"
 
+    # Test pointer creation.
+
+    gdb_test_no_output "gu (define void-pointer-type (type-pointer (arch-void-type (current-arch))))"
+    gdb_scm_test_silent_cmd "gu (define null-pointer (make-value 0 #:type void-pointer-type))" \
+	"test make-value with pointer type"
+    gdb_test "gu (print null-pointer)" "= 0x0"
+    gdb_test "gu (print (equal? (value-type null-pointer) void-pointer-type))" \
+	"= #t"
+
     # Test some invalid operations.
 
     gdb_test_multiple "gu (print (value-add i '()))" "catch error in guile type conversion" {
@@ -237,6 +246,36 @@ proc test_value_numeric_ranges {} {
     }
 }
 
+# Helper routine for test_pointer_numeric_range.
+
+proc test_make_pointer_value { size } {
+    set max [get_max_uint $size]
+    set max_hex [string repeat "f" [expr "$size / 4"]]
+
+    gdb_test "gu (print (make-value $max #:type void-pointer-type))" \
+	"= 0x$max_hex" "test make-value void* max"
+    gdb_test "gu (print (make-value 0 #:type void-pointer-type))" \
+	"= 0x0" "test make-value void* 0"
+
+    gdb_test "gu (print (make-value (+ $max 1) #:type void-pointer-type))" \
+	"ERROR.*Out of range.*" "test make-value void* max+1"
+    gdb_test "gu (print (make-value -1 #:type void-pointer-type))" \
+	"ERROR.*Out of range.*" "test make-value void* -1"
+}
+
+proc test_pointer_numeric_range {} {
+    # We can't assume anything about sizeof (void*) on the target.
+    # Keep it simple for now, this will cover everything important for
+    # the major targets.
+    set pointer_size [get_sizeof "void*" 0]
+    if { $pointer_size == 4 } {
+	test_make_pointer_value 32
+    }
+    if { $pointer_size == 8 } {
+	test_make_pointer_value 64
+    }
+}
+
 proc test_value_boolean {} {
     # Note: Boolean values print as 0,1 because they are printed in the
     # current language (in this case C).
@@ -305,5 +344,6 @@ if ![gdb_guile_runto_main] {
 
 test_value_numeric_ops
 test_value_numeric_ranges
+test_pointer_numeric_range
 test_value_boolean
 test_value_compare
-- 
2.31.1

[PING] [PATCH v2] guile: fix make-value with pointer type

[George Barrett]

Pinging for review. If it looks okay, I'd appreciate if someone could push it
on my behalf.

On Mon, Jun 07, 2021 at 05:56:40AM +1000, George Barrett wrote:
> Calling the `make-value' procedure with an integer value and a pointer
> type for the #:type argument triggers a failed assertion in
> `get_unsigned_type_max', as that function doesn't consider pointers to
> be an unsigned type. This commit fixes the issue by adding a separate
> code path for pointers.
> 
> As previously suggested, range checking is done using a new helper
> function in gdbtypes.
> 
> gdb/ChangeLog:
> 
> 2021-06-07  George Barrett  <bob@bob131.so>
> 
> 	* gdbtypes.h (get_pointer_type_max): Add declaration.
> 	* gdbtypes.c (get_pointer_type_max): Add definition for new
> 	helper function.
> 	* guile/scm-math.c (vlscm_convert_typed_number): Add code path
> 	for handling conversions to pointer types without failing an
> 	assert.
> 
> gdb/testsuite/ChangeLog:
> 
> 2021-06-07  George Barrett  <bob@bob131.so>
> 
> 	* gdb.guile/scm-math.exp (test_value_numeric_ops): Add test
> 	for creating pointers with make-value.
> 	(test_make_pointer_value, test_pointer_numeric_range): Add
> 	test procedures containing checks for integer-to-pointer
> 	validation.
> ---
>  gdb/gdbtypes.c                       | 16 +++++++++++
>  gdb/gdbtypes.h                       |  2 ++
>  gdb/guile/scm-math.c                 | 18 +++++++++++--
>  gdb/testsuite/gdb.guile/scm-math.exp | 40 ++++++++++++++++++++++++++++
>  4 files changed, 74 insertions(+), 2 deletions(-)
> 
> diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
> index 84c4f34cf30..6e74cabc3b3 100644
> --- a/gdb/gdbtypes.c
> +++ b/gdb/gdbtypes.c
> @@ -1931,6 +1931,22 @@ get_signed_type_minmax (struct type *type, LONGEST *min, LONGEST *max)
>    *max = ((ULONGEST) 1 << (n - 1)) - 1;
>  }
>  
> +/* Store in *MAX the largest value representable by pointer type
> +   TYPE. */
> +
> +void
> +get_pointer_type_max (struct type *type, CORE_ADDR *max)
> +{
> +  unsigned int n;
> +
> +  type = check_typedef (type);
> +  gdb_assert (type->code () == TYPE_CODE_PTR);
> +  gdb_assert (TYPE_LENGTH (type) <= sizeof (CORE_ADDR));
> +
> +  n = TYPE_LENGTH (type) * TARGET_CHAR_BIT;
> +  *max = ((((CORE_ADDR) 1 << (n - 1)) - 1) << 1) | 1;
> +}
> +
>  /* Internal routine called by TYPE_VPTR_FIELDNO to return the value of
>     cplus_stuff.vptr_fieldno.
>  
> diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
> index bb4d26eef1a..054a7096f0a 100644
> --- a/gdb/gdbtypes.h
> +++ b/gdb/gdbtypes.h
> @@ -2499,6 +2499,8 @@ extern void get_unsigned_type_max (struct type *, ULONGEST *);
>  
>  extern void get_signed_type_minmax (struct type *, LONGEST *, LONGEST *);
>  
> +extern void get_pointer_type_max (struct type *, CORE_ADDR *);
> +
>  /* * Resolve all dynamic values of a type e.g. array bounds to static values.
>     ADDR specifies the location of the variable the type is bound to.
>     If TYPE has no dynamic properties return TYPE; otherwise a new type with
> diff --git a/gdb/guile/scm-math.c b/gdb/guile/scm-math.c
> index d9fd6718196..84de21cb440 100644
> --- a/gdb/guile/scm-math.c
> +++ b/gdb/guile/scm-math.c
> @@ -524,8 +524,7 @@ vlscm_convert_typed_number (const char *func_name, int obj_arg_pos, SCM obj,
>  			    int type_arg_pos, SCM type_scm, struct type *type,
>  			    struct gdbarch *gdbarch, SCM *except_scmp)
>  {
> -  if (is_integral_type (type)
> -      || type->code () == TYPE_CODE_PTR)
> +  if (is_integral_type (type))
>      {
>        if (type->is_unsigned ())
>  	{
> @@ -558,6 +557,21 @@ vlscm_convert_typed_number (const char *func_name, int obj_arg_pos, SCM obj,
>  	  return value_from_longest (type, gdbscm_scm_to_longest (obj));
>  	}
>      }
> +  else if (type->code () == TYPE_CODE_PTR)
> +    {
> +      CORE_ADDR max;
> +
> +      get_pointer_type_max (type, &max);
> +      if (!scm_is_unsigned_integer (obj, 0, max))
> +	{
> +	  *except_scmp
> +	    = gdbscm_make_out_of_range_error (func_name,
> +					      obj_arg_pos, obj,
> +					_("value out of range for type"));
> +	  return NULL;
> +	}
> +      return value_from_pointer (type, gdbscm_scm_to_ulongest (obj));
> +    }
>    else if (type->code () == TYPE_CODE_FLT)
>      return value_from_host_double (type, scm_to_double (obj));
>    else
> diff --git a/gdb/testsuite/gdb.guile/scm-math.exp b/gdb/testsuite/gdb.guile/scm-math.exp
> index ba975454ce5..ee428e5cc90 100644
> --- a/gdb/testsuite/gdb.guile/scm-math.exp
> +++ b/gdb/testsuite/gdb.guile/scm-math.exp
> @@ -137,6 +137,15 @@ proc test_value_numeric_ops {} {
>      gdb_test "gu (print (value-sub b a))" \
>  	"= 3" "subtract two pointer values"
>  
> +    # Test pointer creation.
> +
> +    gdb_test_no_output "gu (define void-pointer-type (type-pointer (arch-void-type (current-arch))))"
> +    gdb_scm_test_silent_cmd "gu (define null-pointer (make-value 0 #:type void-pointer-type))" \
> +	"test make-value with pointer type"
> +    gdb_test "gu (print null-pointer)" "= 0x0"
> +    gdb_test "gu (print (equal? (value-type null-pointer) void-pointer-type))" \
> +	"= #t"
> +
>      # Test some invalid operations.
>  
>      gdb_test_multiple "gu (print (value-add i '()))" "catch error in guile type conversion" {
> @@ -237,6 +246,36 @@ proc test_value_numeric_ranges {} {
>      }
>  }
>  
> +# Helper routine for test_pointer_numeric_range.
> +
> +proc test_make_pointer_value { size } {
> +    set max [get_max_uint $size]
> +    set max_hex [string repeat "f" [expr "$size / 4"]]
> +
> +    gdb_test "gu (print (make-value $max #:type void-pointer-type))" \
> +	"= 0x$max_hex" "test make-value void* max"
> +    gdb_test "gu (print (make-value 0 #:type void-pointer-type))" \
> +	"= 0x0" "test make-value void* 0"
> +
> +    gdb_test "gu (print (make-value (+ $max 1) #:type void-pointer-type))" \
> +	"ERROR.*Out of range.*" "test make-value void* max+1"
> +    gdb_test "gu (print (make-value -1 #:type void-pointer-type))" \
> +	"ERROR.*Out of range.*" "test make-value void* -1"
> +}
> +
> +proc test_pointer_numeric_range {} {
> +    # We can't assume anything about sizeof (void*) on the target.
> +    # Keep it simple for now, this will cover everything important for
> +    # the major targets.
> +    set pointer_size [get_sizeof "void*" 0]
> +    if { $pointer_size == 4 } {
> +	test_make_pointer_value 32
> +    }
> +    if { $pointer_size == 8 } {
> +	test_make_pointer_value 64
> +    }
> +}
> +
>  proc test_value_boolean {} {
>      # Note: Boolean values print as 0,1 because they are printed in the
>      # current language (in this case C).
> @@ -305,5 +344,6 @@ if ![gdb_guile_runto_main] {
>  
>  test_value_numeric_ops
>  test_value_numeric_ranges
> +test_pointer_numeric_range
>  test_value_boolean
>  test_value_compare
> -- 
> 2.31.1

Re: [PATCH v2] guile: fix make-value with pointer type

[Simon Marchi]

On 2021-06-06 3:56 p.m., George Barrett via Gdb-patches wrote:
> Calling the `make-value' procedure with an integer value and a pointer
> type for the #:type argument triggers a failed assertion in
> `get_unsigned_type_max', as that function doesn't consider pointers to
> be an unsigned type. This commit fixes the issue by adding a separate
> code path for pointers.
> 
> As previously suggested, range checking is done using a new helper
> function in gdbtypes.

Hi George,

This LGTM, with a few nits noted below.

> @@ -1931,6 +1931,22 @@ get_signed_type_minmax (struct type *type, LONGEST *min, LONGEST *max)
>    *max = ((ULONGEST) 1 << (n - 1)) - 1;
>  }
>  
> +/* Store in *MAX the largest value representable by pointer type
> +   TYPE. */
> +
> +void
> +get_pointer_type_max (struct type *type, CORE_ADDR *max)
> +{

Let's use the function's return value to return the max:

  CORE_ADDR
  get_pointer_type_max (struct type *type)

I'd suggest changing get_unsigned_type_max the same way, as a separate
patch.

> @@ -558,6 +557,21 @@ vlscm_convert_typed_number (const char *func_name, int obj_arg_pos, SCM obj,
>  	  return value_from_longest (type, gdbscm_scm_to_longest (obj));
>  	}
>      }
> +  else if (type->code () == TYPE_CODE_PTR)
> +    {
> +      CORE_ADDR max;
> +
> +      get_pointer_type_max (type, &max);
> +      if (!scm_is_unsigned_integer (obj, 0, max))
> +	{
> +	  *except_scmp
> +	    = gdbscm_make_out_of_range_error (func_name,
> +					      obj_arg_pos, obj,
> +					_("value out of range for type"));

The indentaion of that last line is not correct, but I see that you just
copied the code above.  Can you make a follow-patch to fix them all?  In
this case, I would typically do:

	  *except_scmp
	    = gdbscm_make_out_of_range_error
		(func_name, obj_arg_pos, obj, _("value out of range for type"));

Simon

Re: [PATCH v2] guile: fix make-value with pointer type

[George Barrett]

On Wed, Jul 28, 2021 at 10:07:26PM -0400, Simon Marchi wrote:
> On 2021-06-06 3:56 p.m., George Barrett via Gdb-patches wrote:
> > @@ -1931,6 +1931,22 @@ get_signed_type_minmax (struct type *type, LONGEST *min, LONGEST *max)
> >    *max = ((ULONGEST) 1 << (n - 1)) - 1;
> >  }
> >  
> > +/* Store in *MAX the largest value representable by pointer type
> > +   TYPE. */
> > +
> > +void
> > +get_pointer_type_max (struct type *type, CORE_ADDR *max)
> > +{
> 
> Let's use the function's return value to return the max:
> 
>   CORE_ADDR
>   get_pointer_type_max (struct type *type)
> 
> I'd suggest changing get_unsigned_type_max the same way, as a separate
> patch.

Ack.

> > @@ -558,6 +557,21 @@ vlscm_convert_typed_number (const char *func_name, int obj_arg_pos, SCM obj,
> >  	  return value_from_longest (type, gdbscm_scm_to_longest (obj));
> >  	}
> >      }
> > +  else if (type->code () == TYPE_CODE_PTR)
> > +    {
> > +      CORE_ADDR max;
> > +
> > +      get_pointer_type_max (type, &max);
> > +      if (!scm_is_unsigned_integer (obj, 0, max))
> > +	{
> > +	  *except_scmp
> > +	    = gdbscm_make_out_of_range_error (func_name,
> > +					      obj_arg_pos, obj,
> > +					_("value out of range for type"));
> 
> The indentaion of that last line is not correct, but I see that you just
> copied the code above.  Can you make a follow-patch to fix them all?  In
> this case, I would typically do:
> 
> 	  *except_scmp
> 	    = gdbscm_make_out_of_range_error
> 		(func_name, obj_arg_pos, obj, _("value out of range for type"));

So leave the indentation in the patch as-is, but have a follow-up patch fixing
both? Alright.

Thanks.

Re: [PATCH v2] guile: fix make-value with pointer type

[Simon Marchi]

On 2021-07-29 10:28 a.m., George Barrett wrote:
> So leave the indentation in the patch as-is, but have a follow-up patch fixing
> both? Alright.


Yes, or a patch before that fixes the existing code and then your patch
does the right thing.  Nobody should get upset either way.

Simon