[PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[Siva Chandra]

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A call to TYPE_TARGET_TYPE was being done without checking if the type
does have a target type. This was introduced by my commit:
82c48ac732edb0155288a93ef3dd39625ff2d2e1

The attached patch fixes it. This probably qualifies as an obvious
fix, but just in case.

 2014-10-16  Siva Chandra Reddy  <sivachandra@google.com>

        * gnu-v3-abi.c (gnuv3_pass_by_reference): Call TYPE_TARGET_TYPE
        on the arg type of a constructor only if it is of reference type.

[-- Attachment #2: gnuv3_pass_by_reference_v1.txt --]
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diff --git a/gdb/gnu-v3-abi.c b/gdb/gnu-v3-abi.c
index a6c6f9f..b960aa3 100644
--- a/gdb/gnu-v3-abi.c
+++ b/gdb/gnu-v3-abi.c
@@ -1320,13 +1320,15 @@ gnuv3_pass_by_reference (struct type *type)
 	if (TYPE_NFIELDS (fieldtype) == 2)
 	  {
 	    struct type *arg_type = TYPE_FIELD_TYPE (fieldtype, 1);
-	    struct type *arg_target_type;
 
-	    arg_target_type = check_typedef (TYPE_TARGET_TYPE (arg_type));
+	    if (TYPE_CODE (arg_type) == TYPE_CODE_REF)
+	      {
+		struct type *arg_target_type;
 
-	    if (TYPE_CODE (arg_type) == TYPE_CODE_REF
-		&& class_types_same_p (arg_target_type, type))
-	      return 1;
+	        arg_target_type = check_typedef (TYPE_TARGET_TYPE (arg_type));
+		if (class_types_same_p (arg_target_type, type))
+		  return 1;
+	      }
 	  }
       }
 

Re: [PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[Pedro Alves]

Hi Siva,

On 10/16/2014 03:38 PM, Siva Chandra wrote:
> A call to TYPE_TARGET_TYPE was being done without checking if the type
> does have a target type. This was introduced by my commit:
> 82c48ac732edb0155288a93ef3dd39625ff2d2e1
> 
> The attached patch fixes it. This probably qualifies as an obvious
> fix, but just in case.
> 
>  2014-10-16  Siva Chandra Reddy  <sivachandra@google.com>
> 
>         * gnu-v3-abi.c (gnuv3_pass_by_reference): Call TYPE_TARGET_TYPE
>         on the arg type of a constructor only if it is of reference type.
> 

How did you notice this?  Does an existing test catch it?

Thanks,
Pedro Alves

Re: [PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[Siva Chandra]

On Thu, Oct 16, 2014 at 11:01 AM, Pedro Alves <palves@redhat.com> wrote:
>>  2014-10-16  Siva Chandra Reddy  <sivachandra@google.com>
>>
>>         * gnu-v3-abi.c (gnuv3_pass_by_reference): Call TYPE_TARGET_TYPE
>>         on the arg type of a constructor only if it is of reference type.
>>
>
> How did you notice this?  Does an existing test catch it?

I hit it while I was "using" GDB so to say :)
I had a class which had a copy constructor as well as another
constructor taking an argument. It fails when going over the other
constructor.

Do you think a test case should be added? I did think about it, but
then, should there be a test case for every use of TYPE_TARGET_TYPE? I
thought it was more of a "user mistake" in my original patch.

Thank you,
Siva Chandra

Re: [PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[Sergio Durigan Junior]

On Thursday, October 16 2014, Siva Chandra wrote:

> Do you think a test case should be added? I did think about it, but
> then, should there be a test case for every use of TYPE_TARGET_TYPE? I
> thought it was more of a "user mistake" in my original patch.

If I may, I think a testcase should be added for this case, yes.  GDB
should not have a problem because a user mistake.

-- 
Sergio
GPG key ID: 0x65FC5E36
Please send encrypted e-mail if possible
http://sergiodj.net/

Re: [PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[Siva Chandra]

On Thu, Oct 16, 2014 at 11:15 AM, Sergio Durigan Junior
<sergiodj@redhat.com> wrote:
> On Thursday, October 16 2014, Siva Chandra wrote:
>
>> Do you think a test case should be added? I did think about it, but
>> then, should there be a test case for every use of TYPE_TARGET_TYPE? I
>> thought it was more of a "user mistake" in my original patch.
>
> If I may, I think a testcase should be added for this case, yes.  GDB
> should not have a problem because a user mistake.

I will add and send an updated patch. The user mistake I am talking
about here is me as a developer using "TYPE_TARGET_TYPE" in GDB source
code.

Re: [PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[Sergio Durigan Junior]

On Thursday, October 16 2014, Siva Chandra wrote:

> I will add and send an updated patch. The user mistake I am talking
> about here is me as a developer using "TYPE_TARGET_TYPE" in GDB source
> code.

Oh, I see now :-).  Anyway, testcases are always welcome.

-- 
Sergio
GPG key ID: 0x65FC5E36
Please send encrypted e-mail if possible
http://sergiodj.net/

Re: [PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[Siva Chandra]

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The patch updated with a test case is attached.

gdb/ChangeLog:

        * gnu-v3-abi.c (gnuv3_pass_by_reference): Call TYPE_TARGET_TYPE
        on the arg type of a constructor only if it is of reference type.

gdb/testsuite/ChangeLog:

        * gdb.cp/non-trivial-retval.cc: Add a test case.
        * gdb.cp/non-trivial-retval.exp: Add a test.

[-- Attachment #2: gnuv3_pass_by_reference_v2.txt --]
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diff --git a/gdb/gnu-v3-abi.c b/gdb/gnu-v3-abi.c
index a6c6f9f..b960aa3 100644
--- a/gdb/gnu-v3-abi.c
+++ b/gdb/gnu-v3-abi.c
@@ -1320,13 +1320,15 @@ gnuv3_pass_by_reference (struct type *type)
 	if (TYPE_NFIELDS (fieldtype) == 2)
 	  {
 	    struct type *arg_type = TYPE_FIELD_TYPE (fieldtype, 1);
-	    struct type *arg_target_type;
 
-	    arg_target_type = check_typedef (TYPE_TARGET_TYPE (arg_type));
+	    if (TYPE_CODE (arg_type) == TYPE_CODE_REF)
+	      {
+		struct type *arg_target_type;
 
-	    if (TYPE_CODE (arg_type) == TYPE_CODE_REF
-		&& class_types_same_p (arg_target_type, type))
-	      return 1;
+	        arg_target_type = check_typedef (TYPE_TARGET_TYPE (arg_type));
+		if (class_types_same_p (arg_target_type, type))
+		  return 1;
+	      }
 	  }
       }
 
diff --git a/gdb/testsuite/gdb.cp/non-trivial-retval.cc b/gdb/testsuite/gdb.cp/non-trivial-retval.cc
index 8382f40..aeb7875 100644
--- a/gdb/testsuite/gdb.cp/non-trivial-retval.cc
+++ b/gdb/testsuite/gdb.cp/non-trivial-retval.cc
@@ -63,6 +63,33 @@ f2 (int i1, int i2)
   return b;
 }
 
+class B1
+{
+public:
+  B1 () {}
+  B1 (int i);  /* Put this decl before the copy-ctor decl.  */
+  B1 (const B1 &obj);
+
+  int b1;
+};
+
+B1::B1 (const B1 &obj)
+{
+  b1 = obj.b1;
+}
+
+B1::B1 (int i) : b1 (i) { }
+
+B1
+f22 (int i1, int i2)
+{
+  B1 b1;
+
+  b1.b1 = i1 + i2;
+
+  return b1;
+}
+
 class C
 {
 public:
diff --git a/gdb/testsuite/gdb.cp/non-trivial-retval.exp b/gdb/testsuite/gdb.cp/non-trivial-retval.exp
index 7934946..3450a94 100644
--- a/gdb/testsuite/gdb.cp/non-trivial-retval.exp
+++ b/gdb/testsuite/gdb.cp/non-trivial-retval.exp
@@ -32,5 +32,6 @@ gdb_continue_to_breakpoint "Break here"
 
 gdb_test "p f1 (i1, i2)" ".* = {a = 123}" "p f1 (i1, i2)"
 gdb_test "p f2 (i1, i2)" ".* = {b = 123}" "p f2 (i1, i2)"
+gdb_test "p f22 (i1, i2)" ".* = {b1 = 123}" "p f22 (i1, i2)"
 gdb_test "p f3 (i1, i2)" ".* = {.* c = 123}" "p f3 (i1, i2)"
 gdb_test "p f4 (i1, i2)" ".* = {.* e = 123}" "p f4 (i1, i2)"

Re: [PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[Pedro Alves]

On 10/16/2014 08:01 PM, Siva Chandra wrote:
> The patch updated with a test case is attached.

Thank you very much.  FAOD, I'm expecting Doug will review this.

Thanks,
Pedro Alves

Re: [PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[Siva Chandra]

On Thu, Oct 16, 2014 at 12:01 PM, Siva Chandra <sivachandra@google.com> wrote:
> The patch updated with a test case is attached.
>
> gdb/ChangeLog:
>
>         * gnu-v3-abi.c (gnuv3_pass_by_reference): Call TYPE_TARGET_TYPE
>         on the arg type of a constructor only if it is of reference type.
>
> gdb/testsuite/ChangeLog:
>
>         * gdb.cp/non-trivial-retval.cc: Add a test case.
>         * gdb.cp/non-trivial-retval.exp: Add a test.

Ping.

Re: [PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[Doug Evans]

On Thu, Oct 23, 2014 at 12:09 PM, Siva Chandra <sivachandra@google.com> wrote:
> On Thu, Oct 16, 2014 at 12:01 PM, Siva Chandra <sivachandra@google.com> wrote:
>> The patch updated with a test case is attached.
>>
>> gdb/ChangeLog:
>>
>>         * gnu-v3-abi.c (gnuv3_pass_by_reference): Call TYPE_TARGET_TYPE
>>         on the arg type of a constructor only if it is of reference type.
>>
>> gdb/testsuite/ChangeLog:
>>
>>         * gdb.cp/non-trivial-retval.cc: Add a test case.
>>         * gdb.cp/non-trivial-retval.exp: Add a test.
>
> Ping.

LGTM with one nit.

+class B1
+{
+public:
+  B1 () {}
+  B1 (int i);  /* Put this decl before the copy-ctor decl.  */
+  B1 (const B1 &obj);
+
+  int b1;
+};

Can you elaborate on why "Put this decl before ..."?

Re: [PATCH] Guard a call to TYPE_TARGET_TYPE in gnuv3_pass_by_reference

[Siva Chandra]

On Thu, Oct 23, 2014 at 10:31 PM, Doug Evans <dje@google.com> wrote:
>>> gdb/ChangeLog:
>>>
>>>         * gnu-v3-abi.c (gnuv3_pass_by_reference): Call TYPE_TARGET_TYPE
>>>         on the arg type of a constructor only if it is of reference type.
>>>
>>> gdb/testsuite/ChangeLog:
>>>
>>>         * gdb.cp/non-trivial-retval.cc: Add a test case.
>>>         * gdb.cp/non-trivial-retval.exp: Add a test.
>
> LGTM with one nit.
>
> +class B1
> +{
> +public:
> +  B1 () {}
> +  B1 (int i);  /* Put this decl before the copy-ctor decl.  */
> +  B1 (const B1 &obj);
> +
> +  int b1;
> +};
>
> Can you elaborate on why "Put this decl before ..."?

Thank you. Pushed after adding a detailed comment:
3433cfa51f6397231ffe2b2c69298eff89179769