[PATCH v2 0/3] Guile: add value-{reference,const}-value

[PATCH v2 0/3] Guile: add value-{reference,const}-value

[George Barrett]

A couple of simple patches implementing functions missing from the
Guile API (relative to the Python API). Both are straight-forward
translations of the Python implementations.

Feedback on the original series pointed out that the Python API also
has a Value.rvalue_reference_value() method and that a matching
Guile procedure should be introduced alongside value-reference-value,
owing to their similarity. This v2 series updates the patch as
indicated; an additional patch improving the Guile support for rvalue
reference types is included to allow for writing an appropriate test.

George Barrett (3):
  Guile: improve rvalue support
  Guile: add {r,}value-reference-value
  Guile: add value-const-value

 gdb/doc/guile.texi                    | 18 ++++++++
 gdb/guile/scm-type.c                  |  1 +
 gdb/guile/scm-value.c                 | 66 +++++++++++++++++++++++++++
 gdb/testsuite/gdb.guile/scm-value.exp | 13 ++++++
 4 files changed, 98 insertions(+)

-- 
2.30.2

[PATCH v2 1/3] Guile: improve rvalue support

[George Barrett]

Adds a couple of missing bits to the Guile API to make C++11 rvalue
reference values and types usable from Guile scripts.

gdb/ChangeLog:

2021-04-27  George Barrett  <bob@bob131.so>

	* guile/scm-type.c (type_integer_constants): Add binding for
	TYPE_CODE_RVALUE_REF.
	* guile/scm-value.c (gdbscm_value_referenced_value): Handle
	dereferencing of rvalue references.

gdb/doc/ChangeLog:

2021-04-27  George Barrett  <bob@bob131.so>

	* guile.texi (Types In Guile): Add documentation for
	TYPE_CODE_RVALUE_REF.
---
 gdb/doc/guile.texi    | 3 +++
 gdb/guile/scm-type.c  | 1 +
 gdb/guile/scm-value.c | 1 +
 3 files changed, 5 insertions(+)

diff --git a/gdb/doc/guile.texi b/gdb/doc/guile.texi
index 649dac559ad..7f3aa2df5aa 100644
--- a/gdb/doc/guile.texi
+++ b/gdb/doc/guile.texi
@@ -1268,6 +1268,9 @@ A pointer-to-member.
 @item TYPE_CODE_REF
 A reference type.
 
+@item TYPE_CODE_RVALUE_REF
+A C@t{++}11 rvalue reference type.
+
 @item TYPE_CODE_CHAR
 A character type.
 
diff --git a/gdb/guile/scm-type.c b/gdb/guile/scm-type.c
index 11693844edc..8bb3e06482b 100644
--- a/gdb/guile/scm-type.c
+++ b/gdb/guile/scm-type.c
@@ -1318,6 +1318,7 @@ static const scheme_integer_constant type_integer_constants[] =
   X (TYPE_CODE_METHODPTR),
   X (TYPE_CODE_MEMBERPTR),
   X (TYPE_CODE_REF),
+  X (TYPE_CODE_RVALUE_REF),
   X (TYPE_CODE_CHAR),
   X (TYPE_CODE_BOOL),
   X (TYPE_CODE_COMPLEX),
diff --git a/gdb/guile/scm-value.c b/gdb/guile/scm-value.c
index 59995169cd0..f50e8b5b46c 100644
--- a/gdb/guile/scm-value.c
+++ b/gdb/guile/scm-value.c
@@ -476,6 +476,7 @@ gdbscm_value_referenced_value (SCM self)
 	  res_val = value_ind (value);
 	  break;
 	case TYPE_CODE_REF:
+	case TYPE_CODE_RVALUE_REF:
 	  res_val = coerce_ref (value);
 	  break;
 	default:
-- 
2.30.2

Re: [PATCH v2 1/3] Guile: improve rvalue support

[Eli Zaretskii]

> Date: Tue, 27 Apr 2021 05:36:00 +1000
> From: George Barrett via Gdb-patches <gdb-patches@sourceware.org>
> Cc: George Barrett <bob@bob131.so>
> 
> Adds a couple of missing bits to the Guile API to make C++11 rvalue
> reference values and types usable from Guile scripts.
> 
> gdb/ChangeLog:
> 
> 2021-04-27  George Barrett  <bob@bob131.so>
> 
> 	* guile/scm-type.c (type_integer_constants): Add binding for
> 	TYPE_CODE_RVALUE_REF.
> 	* guile/scm-value.c (gdbscm_value_referenced_value): Handle
> 	dereferencing of rvalue references.
> 
> gdb/doc/ChangeLog:
> 
> 2021-04-27  George Barrett  <bob@bob131.so>
> 
> 	* guile.texi (Types In Guile): Add documentation for
> 	TYPE_CODE_RVALUE_REF.

Thanks, the part for the manual is okay.

[PATCH v2 2/3] Guile: add {r,}value-reference-value

[George Barrett]

The Guile API doesn't currently have an equivalent to the Python API's
Value.reference_value() or Value.rvalue_reference_value(). This commit
adds a procedure with equivalent semantics to the Guile API.

gdb/ChangeLog:

2021-04-27  George Barrett  <bob@bob131.so>

	* guile/scm-value.c (gdbscm_reference_value): Add helper
	function for reference value creation.
	(gdbscm_value_reference_value): Add implementation of
	value-reference-value procedure.
	(gdbscm_rvalue_reference_value): Add implementation of
	rvalue-reference-value procedure.
	(value_functions): Add value-reference-value procedure.
	Add rvalue-reference-value procedure.

gdb/doc/ChangeLog:

2021-04-27  George Barrett  <bob@bob131.so>

	* guile.texi (Values From Inferior In Guile): Add
	documentation for value-reference-value.
	Add documentation for rvalue-reference-value.

gdb/testsuite/ChangeLog:

2021-04-27  George Barrett  <bob@bob131.so>

	* gdb.guile/scm-value.exp (test_value_in_inferior): Add test
	for value-reference-value.
	Add test for rvalue-reference-value.
---
 gdb/doc/guile.texi                    | 10 +++++++
 gdb/guile/scm-value.c                 | 42 +++++++++++++++++++++++++++
 gdb/testsuite/gdb.guile/scm-value.exp | 10 +++++++
 3 files changed, 62 insertions(+)

diff --git a/gdb/doc/guile.texi b/gdb/doc/guile.texi
index 7f3aa2df5aa..843858ffb31 100644
--- a/gdb/doc/guile.texi
+++ b/gdb/doc/guile.texi
@@ -801,6 +801,16 @@ The @code{<gdb:value>} object @code{scm-val} is identical to that
 corresponding to @code{val}.
 @end deffn
 
+@deffn {Scheme Procedure} value-reference-value value
+Return a new @code{<gdb:value>} object which is a reference to the value
+encapsulated by @code{<gdb:value>} object @var{value}.
+@end deffn
+
+@deffn {Scheme Procedure} rvalue-reference-value value
+Return a new @code{<gdb:value>} object which is an rvalue reference to
+the value encapsulated by @code{<gdb:value>} object @var{value}.
+@end deffn
+
 @deffn {Scheme Procedure} value-field value field-name
 Return field @var{field-name} from @code{<gdb:value>} object @var{value}.
 @end deffn
diff --git a/gdb/guile/scm-value.c b/gdb/guile/scm-value.c
index f50e8b5b46c..2ab193f044a 100644
--- a/gdb/guile/scm-value.c
+++ b/gdb/guile/scm-value.c
@@ -488,6 +488,38 @@ gdbscm_value_referenced_value (SCM self)
     });
 }
 
+static SCM
+gdbscm_reference_value (SCM self, enum type_code refcode)
+{
+  value_smob *v_smob
+    = vlscm_get_value_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);
+  struct value *value = v_smob->value;
+
+  return gdbscm_wrap ([=]
+    {
+      scoped_value_mark free_values;
+
+      struct value *res_val = value_ref (value, refcode);
+      return vlscm_scm_from_value (res_val);
+    });
+}
+
+/* (value-reference-value <gdb:value>) -> <gdb:value> */
+
+static SCM
+gdbscm_value_reference_value (SCM self)
+{
+  return gdbscm_reference_value (self, TYPE_CODE_REF);
+}
+
+/* (rvalue-reference-value <gdb:value>) -> <gdb:value> */
+
+static SCM
+gdbscm_rvalue_reference_value (SCM self)
+{
+  return gdbscm_reference_value (self, TYPE_CODE_RVALUE_REF);
+}
+
 /* (value-type <gdb:value>) -> <gdb:type> */
 
 static SCM
@@ -1352,6 +1384,16 @@ For example, for a value which is a reference to an 'int' pointer ('int *'),\n\
 value-dereference will result in a value of type 'int' while\n\
 value-referenced-value will result in a value of type 'int *'." },
 
+  { "value-reference-value", 1, 0, 0,
+    as_a_scm_t_subr (gdbscm_value_reference_value),
+    "\
+Return a <gdb:value> object which is a reference to the given value." },
+
+  { "rvalue-reference-value", 1, 0, 0,
+    as_a_scm_t_subr (gdbscm_rvalue_reference_value),
+    "\
+Return a <gdb:value> object which is an rvalue reference to the given value." },
+
   { "value-field", 2, 0, 0, as_a_scm_t_subr (gdbscm_value_field),
     "\
 Return the specified field of the value.\n\
diff --git a/gdb/testsuite/gdb.guile/scm-value.exp b/gdb/testsuite/gdb.guile/scm-value.exp
index 191af1d71a6..883c4bea72e 100644
--- a/gdb/testsuite/gdb.guile/scm-value.exp
+++ b/gdb/testsuite/gdb.guile/scm-value.exp
@@ -173,6 +173,16 @@ proc test_value_in_inferior {} {
 	"get string beyond null"
     gdb_test "gu (print nullst)" \
 	"= divide\\\\000et"
+
+    gdb_scm_test_silent_cmd "gu (define argv-ref (value-reference-value argv))" \
+	"test value-reference-value"
+    gdb_test "gu (equal? argv (value-referenced-value argv-ref))" "#t"
+    gdb_test "gu (eqv? (type-code (value-type argv-ref)) TYPE_CODE_REF)" "#t"
+
+    gdb_scm_test_silent_cmd "gu (define argv-rref (rvalue-reference-value argv))" \
+	"test rvalue-reference-value"
+    gdb_test "gu (equal? argv (value-referenced-value argv-rref))" "#t"
+    gdb_test "gu (eqv? (type-code (value-type argv-rref)) TYPE_CODE_RVALUE_REF)" "#t"
 }
 
 proc test_strings {} {
-- 
2.30.2

Re: [PATCH v2 2/3] Guile: add {r,}value-reference-value

[Eli Zaretskii]

> Date: Tue, 27 Apr 2021 05:36:15 +1000
> From: George Barrett via Gdb-patches <gdb-patches@sourceware.org>
> Cc: George Barrett <bob@bob131.so>
> 
> The Guile API doesn't currently have an equivalent to the Python API's
> Value.reference_value() or Value.rvalue_reference_value(). This commit
> adds a procedure with equivalent semantics to the Guile API.
> 
> gdb/ChangeLog:
> 
> 2021-04-27  George Barrett  <bob@bob131.so>
> 
> 	* guile/scm-value.c (gdbscm_reference_value): Add helper
> 	function for reference value creation.
> 	(gdbscm_value_reference_value): Add implementation of
> 	value-reference-value procedure.
> 	(gdbscm_rvalue_reference_value): Add implementation of
> 	rvalue-reference-value procedure.
> 	(value_functions): Add value-reference-value procedure.
> 	Add rvalue-reference-value procedure.
> 
> gdb/doc/ChangeLog:
> 
> 2021-04-27  George Barrett  <bob@bob131.so>
> 
> 	* guile.texi (Values From Inferior In Guile): Add
> 	documentation for value-reference-value.
> 	Add documentation for rvalue-reference-value.
> 
> gdb/testsuite/ChangeLog:
> 
> 2021-04-27  George Barrett  <bob@bob131.so>
> 
> 	* gdb.guile/scm-value.exp (test_value_in_inferior): Add test
> 	for value-reference-value.
> 	Add test for rvalue-reference-value.

OK for the guile.texi part.

Should this change have a NEWS entry as well?

Re: [PATCH v2 2/3] Guile: add {r,}value-reference-value

[George Barrett]

On Tue, Apr 27, 2021 at 04:59:21PM +0300, Eli Zaretskii wrote:
> OK for the guile.texi part.
> 
> Should this change have a NEWS entry as well?

I'm not sure, I'm not familiar with the rules around that. I'm guessing you
think there ought to be? If so, would you mind giving me a rough sample diff
indicating how the change should look? There appears to only be ten commits
touching both gdb/NEWS and gdb/guile and they all seem to be considerably
larger in scope than this patch series, so I'm not clear on the appropriate
formatting.

Thanks

Re: [PATCH v2 2/3] Guile: add {r,}value-reference-value

[Eli Zaretskii]

> Date: Wed, 28 Apr 2021 01:51:50 +1000
> From: George Barrett <bob@bob131.so>
> Cc: gdb-patches@sourceware.org
> 
> On Tue, Apr 27, 2021 at 04:59:21PM +0300, Eli Zaretskii wrote:
> > OK for the guile.texi part.
> > 
> > Should this change have a NEWS entry as well?
> 
> I'm not sure, I'm not familiar with the rules around that. I'm guessing you
> think there ought to be?

I tend to think so, but I'm also asking others what do they think.

> If so, would you mind giving me a rough sample diff
> indicating how the change should look? There appears to only be ten commits
> touching both gdb/NEWS and gdb/guile and they all seem to be considerably
> larger in scope than this patch series, so I'm not clear on the appropriate
> formatting.

Look in the existing NEWS file in the "Python" section, I think you
will find there enough examples of the style and formatting.

Thanks.

[PATCH v2 3/3] Guile: add value-const-value

[George Barrett]

The Guile API doesn't currently have an equivalent to the Python API's
gdb.Value.const_value(). This commit adds a procedure with equivalent
semantics to the Guile API.

gdb/ChangeLog:

2021-04-27  George Barrett  <bob@bob131.so>

	* guile/scm-value.c (gdbscm_value_const_value): Add
	implementation of value-const-value procedure.
	(value_functions): Add value-const-value procedure.

gdb/doc/ChangeLog:

2021-04-27  George Barrett  <bob@bob131.so>

	* guile.texi (Values From Inferior In Guile): Add
	documentation for value-const-value.

gdb/testsuite/ChangeLog:

2021-04-27  George Barrett  <bob@bob131.so>

	* gdb.guile/scm-value.exp (test_value_in_inferior): Add test
	for value-const-value.
---
 gdb/doc/guile.texi                    |  5 +++++
 gdb/guile/scm-value.c                 | 23 +++++++++++++++++++++++
 gdb/testsuite/gdb.guile/scm-value.exp |  3 +++
 3 files changed, 31 insertions(+)

diff --git a/gdb/doc/guile.texi b/gdb/doc/guile.texi
index 843858ffb31..633a7e2f250 100644
--- a/gdb/doc/guile.texi
+++ b/gdb/doc/guile.texi
@@ -811,6 +811,11 @@ Return a new @code{<gdb:value>} object which is an rvalue reference to
 the value encapsulated by @code{<gdb:value>} object @var{value}.
 @end deffn
 
+@deffn {Scheme Procedure} value-const-value value
+Return a new @code{<gdb:value>} object which is a 'const' version of
+@code{<gdb:value>} object @var{value}.
+@end deffn
+
 @deffn {Scheme Procedure} value-field value field-name
 Return field @var{field-name} from @code{<gdb:value>} object @var{value}.
 @end deffn
diff --git a/gdb/guile/scm-value.c b/gdb/guile/scm-value.c
index 2ab193f044a..fb753aeecf0 100644
--- a/gdb/guile/scm-value.c
+++ b/gdb/guile/scm-value.c
@@ -520,6 +520,24 @@ gdbscm_rvalue_reference_value (SCM self)
   return gdbscm_reference_value (self, TYPE_CODE_RVALUE_REF);
 }
 
+/* (value-const-value <gdb:value>) -> <gdb:value> */
+
+static SCM
+gdbscm_value_const_value (SCM self)
+{
+  value_smob *v_smob
+    = vlscm_get_value_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);
+  struct value *value = v_smob->value;
+
+  return gdbscm_wrap ([=]
+    {
+      scoped_value_mark free_values;
+
+      struct value *res_val = make_cv_value (1, 0, value);
+      return vlscm_scm_from_value (res_val);
+    });
+}
+
 /* (value-type <gdb:value>) -> <gdb:type> */
 
 static SCM
@@ -1394,6 +1412,11 @@ Return a <gdb:value> object which is a reference to the given value." },
     "\
 Return a <gdb:value> object which is an rvalue reference to the given value." },
 
+  { "value-const-value", 1, 0, 0,
+    as_a_scm_t_subr (gdbscm_value_const_value),
+    "\
+Return a <gdb:value> object which is a 'const' version of the given value." },
+
   { "value-field", 2, 0, 0, as_a_scm_t_subr (gdbscm_value_field),
     "\
 Return the specified field of the value.\n\
diff --git a/gdb/testsuite/gdb.guile/scm-value.exp b/gdb/testsuite/gdb.guile/scm-value.exp
index 883c4bea72e..28b0fd83a9f 100644
--- a/gdb/testsuite/gdb.guile/scm-value.exp
+++ b/gdb/testsuite/gdb.guile/scm-value.exp
@@ -183,6 +183,9 @@ proc test_value_in_inferior {} {
 	"test rvalue-reference-value"
     gdb_test "gu (equal? argv (value-referenced-value argv-rref))" "#t"
     gdb_test "gu (eqv? (type-code (value-type argv-rref)) TYPE_CODE_RVALUE_REF)" "#t"
+
+    gdb_test "gu (equal? (value-type (value-const-value argv)) (type-const (value-type argv)))" \
+	"#t"
 }
 
 proc test_strings {} {
-- 
2.30.2

Re: [PATCH v2 3/3] Guile: add value-const-value

[Eli Zaretskii]

> Date: Tue, 27 Apr 2021 05:36:27 +1000
> From: George Barrett via Gdb-patches <gdb-patches@sourceware.org>
> Cc: George Barrett <bob@bob131.so>
> 
> The Guile API doesn't currently have an equivalent to the Python API's
> gdb.Value.const_value(). This commit adds a procedure with equivalent
> semantics to the Guile API.
> 
> gdb/ChangeLog:
> 
> 2021-04-27  George Barrett  <bob@bob131.so>
> 
> 	* guile/scm-value.c (gdbscm_value_const_value): Add
> 	implementation of value-const-value procedure.
> 	(value_functions): Add value-const-value procedure.
> 
> gdb/doc/ChangeLog:
> 
> 2021-04-27  George Barrett  <bob@bob131.so>
> 
> 	* guile.texi (Values From Inferior In Guile): Add
> 	documentation for value-const-value.
> 
> gdb/testsuite/ChangeLog:
> 
> 2021-04-27  George Barrett  <bob@bob131.so>
> 
> 	* gdb.guile/scm-value.exp (test_value_in_inferior): Add test
> 	for value-const-value.

Thanks.

> +@deffn {Scheme Procedure} value-const-value value
> +Return a new @code{<gdb:value>} object which is a 'const' version of
                                                     ^^^^^^^
Please use @samp{const} instead.  In general, ASCII quotes are almost
never correct in Texinfo.

> +@code{<gdb:value>} object @var{value}.

Can you tell me what is the significance of the brackets <..> here?  I
see it is used elsewhere in the manual, but I'm not sure it isn't a
mistake.

Other than that, the patch for the manual is okay.

Re: [PATCH v2 3/3] Guile: add value-const-value

[George Barrett]

On Tue, Apr 27, 2021 at 04:57:31PM +0300, Eli Zaretskii wrote:
> Please use @samp{const} instead.  In general, ASCII quotes are almost
> never correct in Texinfo.

Sure, thanks for the tip! I'll do a v3 shortly.

> Can you tell me what is the significance of the brackets <..> here?  I
> see it is used elsewhere in the manual, but I'm not sure it isn't a
> mistake.

The convention in Guile is that names of types are enclosed in angle brackets.
The addition of angle brackets to type names is implicit in calls to the smob
registration machinery, so the name of the GDB value type in Guile is
"<gdb:value>" even though GDB asks for the registration for "gdb:value".

Thanks.