Re: [PATCH] c++: Avoid narrowing in make_char_string_pack

2022-01-03 Thread Marek Polacek via Gcc-patches 
On Sat, Dec 18, 2021 at 07:43:55PM -0500, Eric Gallager wrote:
> On Fri, Dec 17, 2021 at 5:59 PM Marek Polacek via Gcc-patches
>  wrote:
> >
> > This fixes
> >
> > gcc/cp/parser.c:4618:41: warning: narrowing conversion of '(char)(*(str + 
> > ((sizetype)i)))' from 'char' to 'unsigned char' [-Wnarrowing]
> >  4618 |   unsigned char s[3] = { '\'', str[i], '\'' };
> >   |~^
> >
> > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> >
> 
> Hi, I thought that GCC was built with -Wno-narrowing; has that changed
> since I last checked? 

No, I noticed that warning when compiling parser.i manually.

Here's a thread I found which led to -Wno-narrowing:
.

> I'd support a move to officially switch from
> disabling -Wnarrowing to enabling it instead if that's possible and
> hasn't been done yet. 

I don't know if the issues above have been fixed.  Maybe they have; it's
been a while...

> Also the '(char)(*(str + ((sizetype)i)))' looks
> like some implementation details leaking; is there a bug against
> -Wnarrowing (or the diagnostics system in general) open about that?

Dunno.
 
> > gcc/cp/ChangeLog:
> >
> > * parser.c (make_char_string_pack): Add a cast to const unsigned
> > char *.
> > ---
> >  gcc/cp/parser.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
> > index 44eed7ea638..56232ab029f 100644
> > --- a/gcc/cp/parser.c
> > +++ b/gcc/cp/parser.c
> > @@ -4607,7 +4607,8 @@ make_char_string_pack (tree value)
> >  {
> >tree charvec;
> >tree argpack = make_node (NONTYPE_ARGUMENT_PACK);
> > -  const char *str = TREE_STRING_POINTER (value);
> > +  const unsigned char *str
> > += (const unsigned char *) TREE_STRING_POINTER (value);
> >int i, len = TREE_STRING_LENGTH (value) - 1;
> >tree argvec = make_tree_vec (1);
> >
> >
> > base-commit: d7ca2a79b82c6500ead6ab983d14c609e2124eee
> > --
> > 2.33.1
> >
> 

Marek

Re: [PATCH] c++: Avoid narrowing in make_char_string_pack

2021-12-20 Thread Jason Merrill via Gcc-patches 

On 12/17/21 17:58, Marek Polacek wrote:

This fixes

gcc/cp/parser.c:4618:41: warning: narrowing conversion of '(char)(*(str + 
((sizetype)i)))' from 'char' to 'unsigned char' [-Wnarrowing]
  4618 |   unsigned char s[3] = { '\'', str[i], '\'' };
   |~^

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?


Hmm, odd that STRING_CST and cpp_string differ in the use of unsigned 
char.  The patch is OK>



gcc/cp/ChangeLog:

* parser.c (make_char_string_pack): Add a cast to const unsigned
char *.
---
  gcc/cp/parser.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 44eed7ea638..56232ab029f 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -4607,7 +4607,8 @@ make_char_string_pack (tree value)
  {
tree charvec;
tree argpack = make_node (NONTYPE_ARGUMENT_PACK);
-  const char *str = TREE_STRING_POINTER (value);
+  const unsigned char *str
+= (const unsigned char *) TREE_STRING_POINTER (value);
int i, len = TREE_STRING_LENGTH (value) - 1;
tree argvec = make_tree_vec (1);
  


base-commit: d7ca2a79b82c6500ead6ab983d14c609e2124eee

Re: [PATCH] c++: Avoid narrowing in make_char_string_pack

2021-12-18 Thread Eric Gallager via Gcc-patches 
On Fri, Dec 17, 2021 at 5:59 PM Marek Polacek via Gcc-patches
 wrote:
>
> This fixes
>
> gcc/cp/parser.c:4618:41: warning: narrowing conversion of '(char)(*(str + 
> ((sizetype)i)))' from 'char' to 'unsigned char' [-Wnarrowing]
>  4618 |   unsigned char s[3] = { '\'', str[i], '\'' };
>   |~^
>
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
>

Hi, I thought that GCC was built with -Wno-narrowing; has that changed
since I last checked? I'd support a move to officially switch from
disabling -Wnarrowing to enabling it instead if that's possible and
hasn't been done yet. Also the '(char)(*(str + ((sizetype)i)))' looks
like some implementation details leaking; is there a bug against
-Wnarrowing (or the diagnostics system in general) open about that?

> gcc/cp/ChangeLog:
>
> * parser.c (make_char_string_pack): Add a cast to const unsigned
> char *.
> ---
>  gcc/cp/parser.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
> index 44eed7ea638..56232ab029f 100644
> --- a/gcc/cp/parser.c
> +++ b/gcc/cp/parser.c
> @@ -4607,7 +4607,8 @@ make_char_string_pack (tree value)
>  {
>tree charvec;
>tree argpack = make_node (NONTYPE_ARGUMENT_PACK);
> -  const char *str = TREE_STRING_POINTER (value);
> +  const unsigned char *str
> += (const unsigned char *) TREE_STRING_POINTER (value);
>int i, len = TREE_STRING_LENGTH (value) - 1;
>tree argvec = make_tree_vec (1);
>
>
> base-commit: d7ca2a79b82c6500ead6ab983d14c609e2124eee
> --
> 2.33.1
>

[PATCH] c++: Avoid narrowing in make_char_string_pack

2021-12-17 Thread Marek Polacek via Gcc-patches 
This fixes

gcc/cp/parser.c:4618:41: warning: narrowing conversion of '(char)(*(str + 
((sizetype)i)))' from 'char' to 'unsigned char' [-Wnarrowing]
 4618 |   unsigned char s[3] = { '\'', str[i], '\'' };
  |~^

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

gcc/cp/ChangeLog:

* parser.c (make_char_string_pack): Add a cast to const unsigned
char *.
---
 gcc/cp/parser.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 44eed7ea638..56232ab029f 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -4607,7 +4607,8 @@ make_char_string_pack (tree value)
 {
   tree charvec;
   tree argpack = make_node (NONTYPE_ARGUMENT_PACK);
-  const char *str = TREE_STRING_POINTER (value);
+  const unsigned char *str
+= (const unsigned char *) TREE_STRING_POINTER (value);
   int i, len = TREE_STRING_LENGTH (value) - 1;
   tree argvec = make_tree_vec (1);
 

base-commit: d7ca2a79b82c6500ead6ab983d14c609e2124eee
-- 
2.33.1