diff mbox series

[2/3] c++/modules: Prevent maybe_clone_decl being called multiple times [PR115007]

Message ID 66c5296d.170a0220.3bae0d.0cdc@mx.google.com
State New
Headers show
Series [1/3] c++: Handle ABI for non-polymorphic dynamic classes | expand

Commit Message

Nathaniel Shead Aug. 20, 2024, 11:40 p.m. UTC 
Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?

-- >8 --

The ICE in the linked PR is caused because maybe_clone_decl is not
prepared to be called on a declaration that has already had clones
created; what happens otherwise is that start_preparsed_function early
exits and never sets up cfun, causing a segfault later on.

To fix this we ensure that post_load_processing only calls
maybe_clone_decl if TREE_ASM_WRITTEN has not been marked on the
declaration yet, and (if maybe_clone_decls succeeds) marks this flag on
the decl so that it doesn't get called again later when finalising
deferred vague linkage declarations in c_parse_final_cleanups.

As a bonus this now allows us to only keep the DECL_SAVED_TREE around in
expand_or_defer_fn_1 for modules which have CMIs, which will have
benefits for LTO performance in non-interface TUs.

For clarity we also update the streaming code to do post_load_decls for
maybe in-charge cdtors rather than any DECL_ABSTRACT_P declaration, as
this is more accurate to the decls affected by maybe_clone_body.

	PR c++/115007

gcc/cp/ChangeLog:

	* module.cc (module_state::read_cluster): Replace
	DECL_ABSTRACT_P with DECL_MAYBE_IN_CHARGE_CDTOR_P.
	(post_load_processing): Check and mark TREE_ASM_WRITTEN.
	* semantics.cc (expand_or_defer_fn_1): Use the more specific
	module_maybe_has_cmi_p instead of modules_p.

gcc/testsuite/ChangeLog:

	* g++.dg/modules/virt-6_a.C: New test.
	* g++.dg/modules/virt-6_b.C: New test.

Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
---
 gcc/cp/module.cc                        |  7 ++++---
 gcc/cp/semantics.cc                     |  2 +-
 gcc/testsuite/g++.dg/modules/virt-6_a.C | 13 +++++++++++++
 gcc/testsuite/g++.dg/modules/virt-6_b.C |  6 ++++++
 4 files changed, 24 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/modules/virt-6_a.C
 create mode 100644 gcc/testsuite/g++.dg/modules/virt-6_b.C

Comments

Nathaniel Shead Sept. 2, 2024, 11:45 a.m. UTC | #1 
Ping.

On Wed, Aug 21, 2024 at 09:40:25AM +1000, Nathaniel Shead wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?
> 
> -- >8 --
> 
> The ICE in the linked PR is caused because maybe_clone_decl is not
> prepared to be called on a declaration that has already had clones
> created; what happens otherwise is that start_preparsed_function early
> exits and never sets up cfun, causing a segfault later on.
> 
> To fix this we ensure that post_load_processing only calls
> maybe_clone_decl if TREE_ASM_WRITTEN has not been marked on the
> declaration yet, and (if maybe_clone_decls succeeds) marks this flag on
> the decl so that it doesn't get called again later when finalising
> deferred vague linkage declarations in c_parse_final_cleanups.
> 
> As a bonus this now allows us to only keep the DECL_SAVED_TREE around in
> expand_or_defer_fn_1 for modules which have CMIs, which will have
> benefits for LTO performance in non-interface TUs.
> 
> For clarity we also update the streaming code to do post_load_decls for
> maybe in-charge cdtors rather than any DECL_ABSTRACT_P declaration, as
> this is more accurate to the decls affected by maybe_clone_body.
> 
> 	PR c++/115007
> 
> gcc/cp/ChangeLog:
> 
> 	* module.cc (module_state::read_cluster): Replace
> 	DECL_ABSTRACT_P with DECL_MAYBE_IN_CHARGE_CDTOR_P.
> 	(post_load_processing): Check and mark TREE_ASM_WRITTEN.
> 	* semantics.cc (expand_or_defer_fn_1): Use the more specific
> 	module_maybe_has_cmi_p instead of modules_p.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/modules/virt-6_a.C: New test.
> 	* g++.dg/modules/virt-6_b.C: New test.
> 
> Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
> ---
>  gcc/cp/module.cc                        |  7 ++++---
>  gcc/cp/semantics.cc                     |  2 +-
>  gcc/testsuite/g++.dg/modules/virt-6_a.C | 13 +++++++++++++
>  gcc/testsuite/g++.dg/modules/virt-6_b.C |  6 ++++++
>  4 files changed, 24 insertions(+), 4 deletions(-)
>  create mode 100644 gcc/testsuite/g++.dg/modules/virt-6_a.C
>  create mode 100644 gcc/testsuite/g++.dg/modules/virt-6_b.C
> 
> diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
> index 7c42aea05ee..5cd4f313933 100644
> --- a/gcc/cp/module.cc
> +++ b/gcc/cp/module.cc
> @@ -15525,7 +15525,7 @@ module_state::read_cluster (unsigned snum)
>  
>        if (abstract)
>  	;
> -      else if (DECL_ABSTRACT_P (decl))
> +      else if (DECL_MAYBE_IN_CHARGE_CDTOR_P (decl))
>  	vec_safe_push (post_load_decls, decl);
>        else
>  	{
> @@ -17947,10 +17947,11 @@ post_load_processing ()
>  
>        dump () && dump ("Post-load processing of %N", decl);
>  
> -      gcc_checking_assert (DECL_ABSTRACT_P (decl));
> +      gcc_checking_assert (DECL_MAYBE_IN_CHARGE_CDTOR_P (decl));
>        /* Cloning can cause loading -- specifically operator delete for
>  	 the deleting dtor.  */
> -      maybe_clone_body (decl);
> +      if (!TREE_ASM_WRITTEN (decl) && maybe_clone_body (decl))
> +	TREE_ASM_WRITTEN (decl) = 1;
>      }
>  
>    cfun = old_cfun;
> diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> index 5ab2076b673..f7ae8e68dcf 100644
> --- a/gcc/cp/semantics.cc
> +++ b/gcc/cp/semantics.cc
> @@ -5122,7 +5122,7 @@ expand_or_defer_fn_1 (tree fn)
>  	 demand, so we also need to keep the body.  Otherwise we don't
>  	 need it anymore.  */
>        if (!DECL_DECLARED_CONSTEXPR_P (fn)
> -	  && !(modules_p () && vague_linkage_p (fn)))
> +	  && !(module_maybe_has_cmi_p () && vague_linkage_p (fn)))
>  	DECL_SAVED_TREE (fn) = NULL_TREE;
>        return false;
>      }
> diff --git a/gcc/testsuite/g++.dg/modules/virt-6_a.C b/gcc/testsuite/g++.dg/modules/virt-6_a.C
> new file mode 100644
> index 00000000000..68e466ace3f
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/virt-6_a.C
> @@ -0,0 +1,13 @@
> +// PR c++/115007
> +// { dg-additional-options "-fmodules-ts -Wno-global-module" }
> +// { dg-module-cmi M:a }
> +
> +module;
> +struct S {
> +  virtual ~S() = default;
> +  virtual void f() = 0;
> +};
> +module M:a;
> +extern S* p;
> +template <typename T> void format(T) { p->~S(); }
> +template void format(int);
> diff --git a/gcc/testsuite/g++.dg/modules/virt-6_b.C b/gcc/testsuite/g++.dg/modules/virt-6_b.C
> new file mode 100644
> index 00000000000..c53f5fac742
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/virt-6_b.C
> @@ -0,0 +1,6 @@
> +// PR c++/115007
> +// { dg-additional-options "-fmodules-ts" }
> +// { dg-module-cmi M }
> +
> +export module M;
> +import :a;
> -- 
> 2.43.2
>
Nathaniel Shead Oct. 4, 2024, 12:04 p.m. UTC | #2 
Ping for https://gcc.gnu.org/pipermail/gcc-patches/2024-August/660957.html

On Wed, Aug 21, 2024 at 09:40:25AM +1000, Nathaniel Shead wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?
> 
> -- >8 --
> 
> The ICE in the linked PR is caused because maybe_clone_decl is not
> prepared to be called on a declaration that has already had clones
> created; what happens otherwise is that start_preparsed_function early
> exits and never sets up cfun, causing a segfault later on.
> 
> To fix this we ensure that post_load_processing only calls
> maybe_clone_decl if TREE_ASM_WRITTEN has not been marked on the
> declaration yet, and (if maybe_clone_decls succeeds) marks this flag on
> the decl so that it doesn't get called again later when finalising
> deferred vague linkage declarations in c_parse_final_cleanups.
> 
> As a bonus this now allows us to only keep the DECL_SAVED_TREE around in
> expand_or_defer_fn_1 for modules which have CMIs, which will have
> benefits for LTO performance in non-interface TUs.
> 
> For clarity we also update the streaming code to do post_load_decls for
> maybe in-charge cdtors rather than any DECL_ABSTRACT_P declaration, as
> this is more accurate to the decls affected by maybe_clone_body.
> 
> 	PR c++/115007
> 
> gcc/cp/ChangeLog:
> 
> 	* module.cc (module_state::read_cluster): Replace
> 	DECL_ABSTRACT_P with DECL_MAYBE_IN_CHARGE_CDTOR_P.
> 	(post_load_processing): Check and mark TREE_ASM_WRITTEN.
> 	* semantics.cc (expand_or_defer_fn_1): Use the more specific
> 	module_maybe_has_cmi_p instead of modules_p.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/modules/virt-6_a.C: New test.
> 	* g++.dg/modules/virt-6_b.C: New test.
> 
> Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
> ---
>  gcc/cp/module.cc                        |  7 ++++---
>  gcc/cp/semantics.cc                     |  2 +-
>  gcc/testsuite/g++.dg/modules/virt-6_a.C | 13 +++++++++++++
>  gcc/testsuite/g++.dg/modules/virt-6_b.C |  6 ++++++
>  4 files changed, 24 insertions(+), 4 deletions(-)
>  create mode 100644 gcc/testsuite/g++.dg/modules/virt-6_a.C
>  create mode 100644 gcc/testsuite/g++.dg/modules/virt-6_b.C
> 
> diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
> index 7c42aea05ee..5cd4f313933 100644
> --- a/gcc/cp/module.cc
> +++ b/gcc/cp/module.cc
> @@ -15525,7 +15525,7 @@ module_state::read_cluster (unsigned snum)
>  
>        if (abstract)
>  	;
> -      else if (DECL_ABSTRACT_P (decl))
> +      else if (DECL_MAYBE_IN_CHARGE_CDTOR_P (decl))
>  	vec_safe_push (post_load_decls, decl);
>        else
>  	{
> @@ -17947,10 +17947,11 @@ post_load_processing ()
>  
>        dump () && dump ("Post-load processing of %N", decl);
>  
> -      gcc_checking_assert (DECL_ABSTRACT_P (decl));
> +      gcc_checking_assert (DECL_MAYBE_IN_CHARGE_CDTOR_P (decl));
>        /* Cloning can cause loading -- specifically operator delete for
>  	 the deleting dtor.  */
> -      maybe_clone_body (decl);
> +      if (!TREE_ASM_WRITTEN (decl) && maybe_clone_body (decl))
> +	TREE_ASM_WRITTEN (decl) = 1;
>      }
>  
>    cfun = old_cfun;
> diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> index 5ab2076b673..f7ae8e68dcf 100644
> --- a/gcc/cp/semantics.cc
> +++ b/gcc/cp/semantics.cc
> @@ -5122,7 +5122,7 @@ expand_or_defer_fn_1 (tree fn)
>  	 demand, so we also need to keep the body.  Otherwise we don't
>  	 need it anymore.  */
>        if (!DECL_DECLARED_CONSTEXPR_P (fn)
> -	  && !(modules_p () && vague_linkage_p (fn)))
> +	  && !(module_maybe_has_cmi_p () && vague_linkage_p (fn)))
>  	DECL_SAVED_TREE (fn) = NULL_TREE;
>        return false;
>      }
> diff --git a/gcc/testsuite/g++.dg/modules/virt-6_a.C b/gcc/testsuite/g++.dg/modules/virt-6_a.C
> new file mode 100644
> index 00000000000..68e466ace3f
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/virt-6_a.C
> @@ -0,0 +1,13 @@
> +// PR c++/115007
> +// { dg-additional-options "-fmodules-ts -Wno-global-module" }
> +// { dg-module-cmi M:a }
> +
> +module;
> +struct S {
> +  virtual ~S() = default;
> +  virtual void f() = 0;
> +};
> +module M:a;
> +extern S* p;
> +template <typename T> void format(T) { p->~S(); }
> +template void format(int);
> diff --git a/gcc/testsuite/g++.dg/modules/virt-6_b.C b/gcc/testsuite/g++.dg/modules/virt-6_b.C
> new file mode 100644
> index 00000000000..c53f5fac742
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/virt-6_b.C
> @@ -0,0 +1,6 @@
> +// PR c++/115007
> +// { dg-additional-options "-fmodules-ts" }
> +// { dg-module-cmi M }
> +
> +export module M;
> +import :a;
> -- 
> 2.43.2
>
Jason Merrill Oct. 24, 2024, 4:11 p.m. UTC | #3 
On 8/20/24 7:40 PM, Nathaniel Shead wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?

OK.

> -- >8 --
> 
> The ICE in the linked PR is caused because maybe_clone_decl is not
> prepared to be called on a declaration that has already had clones
> created; what happens otherwise is that start_preparsed_function early
> exits and never sets up cfun, causing a segfault later on.
> 
> To fix this we ensure that post_load_processing only calls
> maybe_clone_decl if TREE_ASM_WRITTEN has not been marked on the
> declaration yet, and (if maybe_clone_decls succeeds) marks this flag on
> the decl so that it doesn't get called again later when finalising
> deferred vague linkage declarations in c_parse_final_cleanups.
> 
> As a bonus this now allows us to only keep the DECL_SAVED_TREE around in
> expand_or_defer_fn_1 for modules which have CMIs, which will have
> benefits for LTO performance in non-interface TUs.
> 
> For clarity we also update the streaming code to do post_load_decls for
> maybe in-charge cdtors rather than any DECL_ABSTRACT_P declaration, as
> this is more accurate to the decls affected by maybe_clone_body.
> 
> 	PR c++/115007
> 
> gcc/cp/ChangeLog:
> 
> 	* module.cc (module_state::read_cluster): Replace
> 	DECL_ABSTRACT_P with DECL_MAYBE_IN_CHARGE_CDTOR_P.
> 	(post_load_processing): Check and mark TREE_ASM_WRITTEN.
> 	* semantics.cc (expand_or_defer_fn_1): Use the more specific
> 	module_maybe_has_cmi_p instead of modules_p.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/modules/virt-6_a.C: New test.
> 	* g++.dg/modules/virt-6_b.C: New test.
> 
> Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
> ---
>   gcc/cp/module.cc                        |  7 ++++---
>   gcc/cp/semantics.cc                     |  2 +-
>   gcc/testsuite/g++.dg/modules/virt-6_a.C | 13 +++++++++++++
>   gcc/testsuite/g++.dg/modules/virt-6_b.C |  6 ++++++
>   4 files changed, 24 insertions(+), 4 deletions(-)
>   create mode 100644 gcc/testsuite/g++.dg/modules/virt-6_a.C
>   create mode 100644 gcc/testsuite/g++.dg/modules/virt-6_b.C
> 
> diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
> index 7c42aea05ee..5cd4f313933 100644
> --- a/gcc/cp/module.cc
> +++ b/gcc/cp/module.cc
> @@ -15525,7 +15525,7 @@ module_state::read_cluster (unsigned snum)
>   
>         if (abstract)
>   	;
> -      else if (DECL_ABSTRACT_P (decl))
> +      else if (DECL_MAYBE_IN_CHARGE_CDTOR_P (decl))
>   	vec_safe_push (post_load_decls, decl);
>         else
>   	{
> @@ -17947,10 +17947,11 @@ post_load_processing ()
>   
>         dump () && dump ("Post-load processing of %N", decl);
>   
> -      gcc_checking_assert (DECL_ABSTRACT_P (decl));
> +      gcc_checking_assert (DECL_MAYBE_IN_CHARGE_CDTOR_P (decl));
>         /* Cloning can cause loading -- specifically operator delete for
>   	 the deleting dtor.  */
> -      maybe_clone_body (decl);
> +      if (!TREE_ASM_WRITTEN (decl) && maybe_clone_body (decl))
> +	TREE_ASM_WRITTEN (decl) = 1;
>       }
>   
>     cfun = old_cfun;
> diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> index 5ab2076b673..f7ae8e68dcf 100644
> --- a/gcc/cp/semantics.cc
> +++ b/gcc/cp/semantics.cc
> @@ -5122,7 +5122,7 @@ expand_or_defer_fn_1 (tree fn)
>   	 demand, so we also need to keep the body.  Otherwise we don't
>   	 need it anymore.  */
>         if (!DECL_DECLARED_CONSTEXPR_P (fn)
> -	  && !(modules_p () && vague_linkage_p (fn)))
> +	  && !(module_maybe_has_cmi_p () && vague_linkage_p (fn)))
>   	DECL_SAVED_TREE (fn) = NULL_TREE;
>         return false;
>       }
> diff --git a/gcc/testsuite/g++.dg/modules/virt-6_a.C b/gcc/testsuite/g++.dg/modules/virt-6_a.C
> new file mode 100644
> index 00000000000..68e466ace3f
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/virt-6_a.C
> @@ -0,0 +1,13 @@
> +// PR c++/115007
> +// { dg-additional-options "-fmodules-ts -Wno-global-module" }
> +// { dg-module-cmi M:a }
> +
> +module;
> +struct S {
> +  virtual ~S() = default;
> +  virtual void f() = 0;
> +};
> +module M:a;
> +extern S* p;
> +template <typename T> void format(T) { p->~S(); }
> +template void format(int);
> diff --git a/gcc/testsuite/g++.dg/modules/virt-6_b.C b/gcc/testsuite/g++.dg/modules/virt-6_b.C
> new file mode 100644
> index 00000000000..c53f5fac742
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/virt-6_b.C
> @@ -0,0 +1,6 @@
> +// PR c++/115007
> +// { dg-additional-options "-fmodules-ts" }
> +// { dg-module-cmi M }
> +
> +export module M;
> +import :a;
diff mbox series

Patch

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 7c42aea05ee..5cd4f313933 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -15525,7 +15525,7 @@  module_state::read_cluster (unsigned snum)
 
       if (abstract)
 	;
-      else if (DECL_ABSTRACT_P (decl))
+      else if (DECL_MAYBE_IN_CHARGE_CDTOR_P (decl))
 	vec_safe_push (post_load_decls, decl);
       else
 	{
@@ -17947,10 +17947,11 @@  post_load_processing ()
 
       dump () && dump ("Post-load processing of %N", decl);
 
-      gcc_checking_assert (DECL_ABSTRACT_P (decl));
+      gcc_checking_assert (DECL_MAYBE_IN_CHARGE_CDTOR_P (decl));
       /* Cloning can cause loading -- specifically operator delete for
 	 the deleting dtor.  */
-      maybe_clone_body (decl);
+      if (!TREE_ASM_WRITTEN (decl) && maybe_clone_body (decl))
+	TREE_ASM_WRITTEN (decl) = 1;
     }
 
   cfun = old_cfun;
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 5ab2076b673..f7ae8e68dcf 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -5122,7 +5122,7 @@  expand_or_defer_fn_1 (tree fn)
 	 demand, so we also need to keep the body.  Otherwise we don't
 	 need it anymore.  */
       if (!DECL_DECLARED_CONSTEXPR_P (fn)
-	  && !(modules_p () && vague_linkage_p (fn)))
+	  && !(module_maybe_has_cmi_p () && vague_linkage_p (fn)))
 	DECL_SAVED_TREE (fn) = NULL_TREE;
       return false;
     }
diff --git a/gcc/testsuite/g++.dg/modules/virt-6_a.C b/gcc/testsuite/g++.dg/modules/virt-6_a.C
new file mode 100644
index 00000000000..68e466ace3f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/virt-6_a.C
@@ -0,0 +1,13 @@ 
+// PR c++/115007
+// { dg-additional-options "-fmodules-ts -Wno-global-module" }
+// { dg-module-cmi M:a }
+
+module;
+struct S {
+  virtual ~S() = default;
+  virtual void f() = 0;
+};
+module M:a;
+extern S* p;
+template <typename T> void format(T) { p->~S(); }
+template void format(int);
diff --git a/gcc/testsuite/g++.dg/modules/virt-6_b.C b/gcc/testsuite/g++.dg/modules/virt-6_b.C
new file mode 100644
index 00000000000..c53f5fac742
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/virt-6_b.C
@@ -0,0 +1,6 @@ 
+// PR c++/115007
+// { dg-additional-options "-fmodules-ts" }
+// { dg-module-cmi M }
+
+export module M;
+import :a;