Re: [PATCH] c++: section attribute on templates [PR70435, PR88061]

[Jason Merrill <jason@redhat.com>]

On 12/14/23 14:17, Patrick Palka wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> trunk?

OK.

> -- >8 --
> 
> The section attribute currently has no effect on templates because the
> call to set_decl_section_name only happens at parse time and not also at
> instantiation time.  This patch fixes this by propagating the section
> name from the template to the instantiation.
> 
> 	PR c++/70435
> 	PR c++/88061
> 
> gcc/cp/ChangeLog:
> 
> 	* pt.cc (tsubst_function_decl): Call set_decl_section_name.
> 	(tsubst_decl) <case VAR_DECL>: Likewise.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/ext/attr-section1.C: New test.
> 	* g++.dg/ext/attr-section1a.C: New test.
> 	* g++.dg/ext/attr-section2.C: New test.
> 	* g++.dg/ext/attr-section2a.C: New test.
> ---
>   gcc/cp/pt.cc                              |  4 ++++
>   gcc/testsuite/g++.dg/ext/attr-section1.C  |  9 +++++++++
>   gcc/testsuite/g++.dg/ext/attr-section1a.C | 11 +++++++++++
>   gcc/testsuite/g++.dg/ext/attr-section2.C  |  9 +++++++++
>   gcc/testsuite/g++.dg/ext/attr-section2a.C | 14 ++++++++++++++
>   5 files changed, 47 insertions(+)
>   create mode 100644 gcc/testsuite/g++.dg/ext/attr-section1.C
>   create mode 100644 gcc/testsuite/g++.dg/ext/attr-section1a.C
>   create mode 100644 gcc/testsuite/g++.dg/ext/attr-section2.C
>   create mode 100644 gcc/testsuite/g++.dg/ext/attr-section2a.C
> 
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index 50e6f062c85..8c4174fb902 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -14607,6 +14607,8 @@ tsubst_function_decl (tree t, tree args, tsubst_flags_t complain,
>   	= remove_attribute ("visibility", DECL_ATTRIBUTES (r));
>       }
>     determine_visibility (r);
> +  if (DECL_SECTION_NAME (t))
> +    set_decl_section_name (r, t);
>     if (DECL_DEFAULTED_OUTSIDE_CLASS_P (r)
>         && !processing_template_decl)
>       defaulted_late_check (r);
> @@ -15423,6 +15425,8 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain,
>   		  = remove_attribute ("visibility", DECL_ATTRIBUTES (r));
>   	      }
>   	    determine_visibility (r);
> +	    if (!local_p && DECL_SECTION_NAME (t))
> +	      set_decl_section_name (r, t);
>   	  }
>   
>   	if (!local_p)
> diff --git a/gcc/testsuite/g++.dg/ext/attr-section1.C b/gcc/testsuite/g++.dg/ext/attr-section1.C
> new file mode 100644
> index 00000000000..b8ac65baa93
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/attr-section1.C
> @@ -0,0 +1,9 @@
> +// PR c++/70435
> +// { dg-do compile { target { c++11 && named_sections } } }
> +
> +template<class T>
> +[[gnu::section(".foo")]] void fun() { }
> +
> +template void fun<int>();
> +
> +// { dg-final { scan-assembler {.section[ \t]+.foo} } }
> diff --git a/gcc/testsuite/g++.dg/ext/attr-section1a.C b/gcc/testsuite/g++.dg/ext/attr-section1a.C
> new file mode 100644
> index 00000000000..be24be2fc95
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/attr-section1a.C
> @@ -0,0 +1,11 @@
> +// PR c++/70435
> +// { dg-do compile { target { c++11 && named_sections } } }
> +
> +template<class T>
> +struct A {
> +  [[gnu::section(".foo")]] void fun() { }
> +};
> +
> +template struct A<int>;
> +
> +// { dg-final { scan-assembler {.section[ \t]+.foo} } }
> diff --git a/gcc/testsuite/g++.dg/ext/attr-section2.C b/gcc/testsuite/g++.dg/ext/attr-section2.C
> new file mode 100644
> index 00000000000..a76f43b346f
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/attr-section2.C
> @@ -0,0 +1,9 @@
> +// PR c++/88061
> +// { dg-do compile { target { c++14 && named_sections } } }
> +
> +template<class T>
> +[[gnu::section(".foo")]] int var = 42;
> +
> +template int var<int>;
> +
> +// { dg-final { scan-assembler {.section[ \t]+.foo} } }
> diff --git a/gcc/testsuite/g++.dg/ext/attr-section2a.C b/gcc/testsuite/g++.dg/ext/attr-section2a.C
> new file mode 100644
> index 00000000000..a0b01cd8d93
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/attr-section2a.C
> @@ -0,0 +1,14 @@
> +// PR c++/88061
> +// { dg-do compile { target { c++11 && named_sections } } }
> +
> +template<class T>
> +struct A {
> +  [[gnu::section(".foo")]] static int var;
> +};
> +
> +template<class T>
> +int A<T>::var = 42;
> +
> +template struct A<int>;
> +
> +// { dg-final { scan-assembler {.section[ \t]+.foo} } }