RE: [PATCH 1/1] gdb: Use a typedef's scoped type name to identify local typefs

["Schimpe, Christina" <christina.schimpe@intel.com>]

Hi Bruno, 

Thanks for the review. 
I investigated again the change from types_equal to explicitly comparing names and agree.
The change from types_equal to explicitly comparing names is not required. I missed that.
I will send a v2 soon.

Best,
Christina

-----Original Message-----
From: Bruno Larsen <blarsen@redhat.com> 
Sent: Thursday, November 25, 2021 3:13 PM
To: Schimpe, Christina <christina.schimpe@intel.com>; gdb-patches@sourceware.org
Subject: Re: [PATCH 1/1] gdb: Use a typedef's scoped type name to identify local typefs


Thanks for looking at this. I only have one question, and a minor comment

On 11/25/21 08:16, Christina Schimpe via Gdb-patches wrote:
> GDB prints the wrong type for typedefs in case there is another 
> typedef available for the same raw type (gdb/16040).  The reason is 
> that the current hashmap based substitution mechanism always compares 
> the target type of a typedef and not its scoped name.
> 
> The original output of GDB for a program like
> 
> ~~~~
> namespace ns
> {
>    typedef double scoped_double;
> }
> 
> typedef double global_double;
> 
> class TypedefHolder
> {
> public:
>    double a;
>    ns::scoped_double b;
>    global_double c;
> 
> private:
>    typedef double class_double;
>    class_double d;
> 
>    double method1(ns::scoped_double) { return 24.0; }
>    double method2(global_double) { return 24.0; } };
> 
> int main()
> {
>    TypedefHolder th;
>    return 0;
> }
> ~~~~
> 
> is
> ~~~~
> 
> (gdb) b 27
> Breakpoint 1 at 0x1131: file TypedefHolder.cc, line 27.
> (gdb) r
> Starting program: /tmp/typedefholder
> 
> Breakpoint 1, main () at TypedefHolder.cc:27
> 27	  return 0;
> (gdb) ptype th
> type = class TypedefHolder {
>    public:
>      class_double a;
>      class_double b;
>      class_double c;
>    private:
>      class_double d;
> 
>      class_double method1(class_double);
>      class_double method2(class_double);
> 
>      typedef double class_double;
> }
> ~~~~
> 
> Basically all attributes of a class which have the raw type "double" 
> are substituted by "class_double".
> 
> With the patch the output is the following
> 
> ~~~~
> type = class TypedefHolder {
>    public:
>      double a;
>      ns::scoped_double b;
>      global_double c;
>    private:
>      class_double d;
> 
>      double method1(ns::scoped_double);
>      double method2(global_double);
> 
>      typedef double class_double;
> }
> ~~~~
> 
> Any feedback about this patch is appreciated.
> 
> gdb/ChangeLog:
> 2021-11-25  Christina Schimpe  <christina.schimpe@intel.com>
> 	* gdb/typeprint.c: Change typedef comparison value.
> 
> gdb/testsuite/ChangeLog:
> 2021-11-25  Christina Schimpe  <christina.schimpe@intel.com>
> 	* gdb.cp/ptype-flags.cc: New test class.
> 	* gdb.cp/ptype-flags.exp: New test.
We don't require changelogs anymore, only if the patch is going to gdb-11-branch.

> ---
>   gdb/testsuite/gdb.cp/ptype-flags.cc  | 23 ++++++++
>   gdb/testsuite/gdb.cp/ptype-flags.exp | 88 ++++++++++++++++++++++------
>   gdb/typeprint.c                      |  6 +-
>   3 files changed, 97 insertions(+), 20 deletions(-)
> 
> diff --git a/gdb/testsuite/gdb.cp/ptype-flags.cc 
> b/gdb/testsuite/gdb.cp/ptype-flags.cc
> index fc92d3950c..564d272e57 100644
> --- a/gdb/testsuite/gdb.cp/ptype-flags.cc
> +++ b/gdb/testsuite/gdb.cp/ptype-flags.cc
> @@ -38,7 +38,30 @@ public:
>     double method(void) { return 23.0; }
>   };
>   
> +namespace ns
> +{
> +  typedef double scoped_double;
> +}
> +
> +typedef double global_double;
> +
> +class TypedefHolder
> +{
> +public:
> +  double a;
> +  ns::scoped_double b;
> +  global_double c;
> +
> +private:
> +  typedef double class_double;
> +  class_double d;
> +
> +  double method1(ns::scoped_double) { return 24.0; }
> +  double method2(global_double) { return 24.0; } };
> +
>   Holder<int> value;
> +TypedefHolder value2;
>   
>   int main()
>   {
> diff --git a/gdb/testsuite/gdb.cp/ptype-flags.exp 
> b/gdb/testsuite/gdb.cp/ptype-flags.exp
> index c368415793..c41e8f8744 100644
> --- a/gdb/testsuite/gdb.cp/ptype-flags.exp
> +++ b/gdb/testsuite/gdb.cp/ptype-flags.exp
> @@ -33,7 +33,9 @@ if ![runto_main] then {
>   gdb_test_no_output "set language c++" ""
>   gdb_test_no_output "set width 0" ""
>   
> -proc do_check {name {flags ""} {show_typedefs 1} {show_methods 1} 
> {raw 0}} {
> +proc do_check_holder \
> +    {name {flags ""} {show_typedefs 1} {show_methods 1} {raw 0}} {
> +
>       set contents {
>   	{ base "public Base<T>" }
>   	{ field public "Simple<T> t;" }
> @@ -62,24 +64,76 @@ proc do_check {name {flags ""} {show_typedefs 1} {show_methods 1} {raw 0}} {
>   	"" {} $flags
>   }
>   
> -do_check "basic test"
> -do_check "no methods" "/m" 1 0
> -do_check "no typedefs" "/t" 0 1
> -do_check "no methods or typedefs" "/mt" 0 0
> +proc do_check_typedef_holder \
> +    {name {flags ""} {show_typedefs 1} {show_methods 1} {raw 0}} {
> +
> +    set contents {
> +	{ field public "double a;" }
> +	{ field public "ns::scoped_double b;" }
> +	{ field public "global_double c;" }
> +    }
> +
> +    if {$show_typedefs} {
> +	lappend contents { typedef private "typedef double class_double;" }
> +    }
> +
> +    if {$show_methods} {
> +	lappend contents { method private "double method1(ns::scoped_double);" }
> +	lappend contents { method private "double method2(global_double);" }
> +    }
> +
> +    if {$raw} {
> +	lappend contents { field private "TypedefHolder::class_double d;" }
> +    } else {
> +	lappend contents { field private "class_double d;" }
> +    }
> +
> +    cp_test_ptype_class value2 $name "class" "TypedefHolder" $contents \
> +	"" {} $flags
> +}
>   
> -do_check "raw" "/r" 1 1 1
> -do_check "raw no methods" "/rm" 1 0 1 -do_check "raw no typedefs" 
> "/rt" 0 1 1 -do_check "raw no methods or typedefs" "/rmt" 0 0 1
> +do_check_holder "basic test"
> +do_check_holder "no methods" "/m" 1 0 do_check_holder "no typedefs" 
> +"/t" 0 1 do_check_holder "no methods or typedefs" "/mt" 0 0 
> +do_check_typedef_holder "typdefs class: basic test"
> +do_check_typedef_holder "typdefs class: no methods" "/m" 1 0 
> +do_check_typedef_holder "typdefs class: no typedefs" "/t" 0 1 0 
> +do_check_typedef_holder "typdefs class:no methods or typedefs" "/mt" 
> +0 0
> +
> +do_check_holder "raw" "/r" 1 1 1
> +do_check_holder "raw no methods" "/rm" 1 0 1 do_check_holder "raw no 
> +typedefs" "/rt" 0 1 1 do_check_holder "raw no methods or typedefs" 
> +"/rmt" 0 0 1 do_check_typedef_holder "typedef class: raw" "/r" 1 1 1 
> +do_check_typedef_holder "typedef class: raw no methods" "/rm" 1 0 1 
> +do_check_typedef_holder "typedef class: raw no typedefs" "/rt" 0 1 1 
> +do_check_typedef_holder "typedef class: raw no methods or typedefs" 
> +"/rmt" 0 0 1
>   
>   gdb_test_no_output "set print type methods off"
> -do_check "basic test, default methods off" "" 1 0 -do_check "methods, 
> default methods off" "/M" 1 1 -do_check "no typedefs, default methods 
> off" "/t" 0 0 -do_check "methods, no typedefs, default methods off" 
> "/Mt" 0 1
> +do_check_holder "basic test, default methods off" "" 1 0 
> +do_check_holder "methods, default methods off" "/M" 1 1 
> +do_check_holder "no typedefs, default methods off" "/t" 0 0 
> +do_check_holder "methods, no typedefs, default methods off" "/Mt" 0 1 
> +do_check_typedef_holder \
> +    "typedef class: basic test, default methods off" "" 1 0 
> +do_check_typedef_holder \
> +    "typedef class: methods, default methods off" "/M" 1 1 
> +do_check_typedef_holder \
> +    "typedef class: no typedefs, default methods off" "/t" 0 0 
> +do_check_typedef_holder \
> +    "typedef class: methods, no typedefs, default methods off" "/Mt" 
> +0 1
>   
>   gdb_test_no_output "set print type typedefs off"
> -do_check "basic test, default methods+typedefs off" "" 0 0 -do_check 
> "methods, default methods+typedefs off" "/M" 0 1 -do_check "typedefs, 
> default methods+typedefs off" "/T" 1 0 -do_check "methods typedefs, 
> default methods+typedefs off" "/MT" 1 1
> +do_check_holder "basic test, default methods+typedefs off" "" 0 0 
> +do_check_holder "methods, default methods+typedefs off" "/M" 0 1 
> +do_check_holder "typedefs, default methods+typedefs off" "/T" 1 0 
> +do_check_holder "methods typedefs, default methods+typedefs off" 
> +"/MT" 1 1 do_check_typedef_holder \
> +    "typedef class: basic test, default methods+typedefs off" "" 0 0 
> +do_check_typedef_holder \
> +    "typedef class: methods, default methods+typedefs off" "/M" 0 1 
> +do_check_typedef_holder \
> +    "typedef class: typedefs, default methods+typedefs off" "/T" 1 0 
> +do_check_typedef_holder \
> +    "typedef class: methods typedefs, default methods+typedefs off" 
> +"/MT" 1 1
> diff --git a/gdb/typeprint.c b/gdb/typeprint.c index 
> 1312111b60..f1b0ce0a71 100644
> --- a/gdb/typeprint.c
> +++ b/gdb/typeprint.c
> @@ -201,9 +201,8 @@ static hashval_t
>   hash_typedef_field (const void *p)
>   {
>     const struct decl_field *tf = (const struct decl_field *) p;
> -  struct type *t = check_typedef (tf->type);
>   
> -  return htab_hash_string (TYPE_SAFE_NAME (t));
> +  return htab_hash_string (TYPE_SAFE_NAME (tf->type));
>   }
>   
>   /* An equality function for a typedef field.  */ @@ -214,7 +213,8 @@ 
> eq_typedef_field (const void *a, const void *b)
>     const struct decl_field *tfa = (const struct decl_field *) a;
>     const struct decl_field *tfb = (const struct decl_field *) b;
>   
> -  return types_equal (tfa->type, tfb->type);
> +  return (tfa->type->name () && tfb->type->name ()
> +    && (strcmp (tfa->type->name (), tfb->type->name ()) == 0));
>   }

Why did you change from types_equal to explicitly comparing names? Types_equal already makes this comparison, and if I put it back in the code, your testcase still passes. Am I mising something?

>   
>   /* See typeprint.h.  */
> 


--
Cheers!
Bruno Larsen

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