* [PATCH] c++: Fix value-init crash in template [PR93676] @ 2020-02-11 19:55 Marek Polacek 2020-02-13 23:24 ` Jason Merrill 0 siblings, 1 reply; 11+ messages in thread From: Marek Polacek @ 2020-02-11 19:55 UTC (permalink / raw) To: Jason Merrill, GCC Patches Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we attempt to value-initialize in build_vec_init even when there's no initializer but the type has a constexpr default constructor. But build_value_init doesn't work in templates, so I think let's avoid this scenario; we'll go to the normal build_aggr_init path then. Bootstrapped/regtested on x86_64-linux, ok for trunk and branches? PR c++/93676 - value-init crash in template. * init.c (build_vec_init): Don't perform value-init in a template. * g++.dg/cpp0x/nsdmi-template19.C: New test. --- gcc/cp/init.c | 2 +- gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ 2 files changed, 14 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C diff --git a/gcc/cp/init.c b/gcc/cp/init.c index d480660445e..c9c0f03c58b 100644 --- a/gcc/cp/init.c +++ b/gcc/cp/init.c @@ -4520,7 +4520,7 @@ build_vec_init (tree base, tree maxindex, tree init, We do need to keep going if we're copying an array. */ - if (try_const && !init) + if (try_const && !init && !processing_template_decl) /* With a constexpr default constructor, which we checked for when setting try_const above, default-initialization is equivalent to value-initialization, and build_value_init gives us something more diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C new file mode 100644 index 00000000000..f3e2cb87fd6 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C @@ -0,0 +1,13 @@ +// PR c++/93676 - value-init crash in template. +// { dg-do compile { target c++11 } } + +struct P { + int x = 0; +}; + +template<class T> +struct S { + S() { new P[2][2]; } +}; + +S<int> s; base-commit: 7a775242ea296849a34ce27de179eaaec411e880 -- Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] c++: Fix value-init crash in template [PR93676] 2020-02-11 19:55 [PATCH] c++: Fix value-init crash in template [PR93676] Marek Polacek @ 2020-02-13 23:24 ` Jason Merrill 2020-02-19 21:15 ` [PATCH v2] " Marek Polacek 0 siblings, 1 reply; 11+ messages in thread From: Jason Merrill @ 2020-02-13 23:24 UTC (permalink / raw) To: Marek Polacek, GCC Patches On 2/11/20 8:54 PM, Marek Polacek wrote: > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > attempt to value-initialize in build_vec_init even when there's no > initializer but the type has a constexpr default constructor. But > build_value_init doesn't work in templates, so I think let's avoid > this scenario; we'll go to the normal build_aggr_init path then. > > Bootstrapped/regtested on x86_64-linux, ok for trunk and branches? > > PR c++/93676 - value-init crash in template. > * init.c (build_vec_init): Don't perform value-init in a template. Hmm, we really shouldn't even be calling build_vec_init in a template, that builds up a lot of garbage that we'll throw away at the end of build_new. Jason ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2] c++: Fix value-init crash in template [PR93676] 2020-02-13 23:24 ` Jason Merrill @ 2020-02-19 21:15 ` Marek Polacek 2020-02-20 0:13 ` Jason Merrill 0 siblings, 1 reply; 11+ messages in thread From: Marek Polacek @ 2020-02-19 21:15 UTC (permalink / raw) To: Jason Merrill; +Cc: GCC Patches On Fri, Feb 14, 2020 at 12:24:30AM +0100, Jason Merrill wrote: > On 2/11/20 8:54 PM, Marek Polacek wrote: > > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > > attempt to value-initialize in build_vec_init even when there's no > > initializer but the type has a constexpr default constructor. But > > build_value_init doesn't work in templates, so I think let's avoid > > this scenario; we'll go to the normal build_aggr_init path then. > > > > Bootstrapped/regtested on x86_64-linux, ok for trunk and branches? > > > > PR c++/93676 - value-init crash in template. > > * init.c (build_vec_init): Don't perform value-init in a template. > > Hmm, we really shouldn't even be calling build_vec_init in a template, that > builds up a lot of garbage that we'll throw away at the end of build_new. Ah, it's true that build_new will just creates a NEW_EXPR in a template and doesn't use the result of build_new_1. Unfortunately I can't just call build_special_member_call like we do in build_new_1 since that crashes for array types. Maybe just return NULL_TREE then? I was afraid we would miss diagnostics but it seems to work. Bootstrapped/regtested on x86_64-linux, ok for trunk? -- >8 -- Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we attempt to value-initialize in build_vec_init even when there's no initializer but the type has a constexpr default constructor. But build_value_init doesn't work in templates, and build_vec_init creates a lot of garbage that would not be used anyway, so don't call it in a template. PR c++/93676 - value-init crash in template. * init.c (build_new_1): Don't call build_vec_init in a template. * g++.dg/cpp0x/nsdmi-template19.C: New test. --- gcc/cp/init.c | 6 ++++++ gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ 2 files changed, 19 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C diff --git a/gcc/cp/init.c b/gcc/cp/init.c index d480660445e..332a9b04679 100644 --- a/gcc/cp/init.c +++ b/gcc/cp/init.c @@ -3554,6 +3554,12 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, error ("parenthesized initializer in array new"); return error_mark_node; } + /* We shouldn't call build_vec_init in a template: it could call + build_value_init which doesn't work in templates, and it would + create a lot of garbage that would not be used anyway, so return + a null tree and let build_new create a NEW_EXPR instead. */ + if (processing_template_decl) + return NULL_TREE; init_expr = build_vec_init (data_addr, cp_build_binary_op (input_location, diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C new file mode 100644 index 00000000000..f3e2cb87fd6 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C @@ -0,0 +1,13 @@ +// PR c++/93676 - value-init crash in template. +// { dg-do compile { target c++11 } } + +struct P { + int x = 0; +}; + +template<class T> +struct S { + S() { new P[2][2]; } +}; + +S<int> s; base-commit: 58f2e59ad36ca05444cb0a57ad1f13cc58e52755 -- Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2] c++: Fix value-init crash in template [PR93676] 2020-02-19 21:15 ` [PATCH v2] " Marek Polacek @ 2020-02-20 0:13 ` Jason Merrill 2020-02-20 16:52 ` [PATCH v3] " Marek Polacek 0 siblings, 1 reply; 11+ messages in thread From: Jason Merrill @ 2020-02-20 0:13 UTC (permalink / raw) To: Marek Polacek; +Cc: GCC Patches On 2/19/20 10:15 PM, Marek Polacek wrote: > On Fri, Feb 14, 2020 at 12:24:30AM +0100, Jason Merrill wrote: >> On 2/11/20 8:54 PM, Marek Polacek wrote: >>> Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we >>> attempt to value-initialize in build_vec_init even when there's no >>> initializer but the type has a constexpr default constructor. But >>> build_value_init doesn't work in templates, so I think let's avoid >>> this scenario; we'll go to the normal build_aggr_init path then. >>> >>> Bootstrapped/regtested on x86_64-linux, ok for trunk and branches? >>> >>> PR c++/93676 - value-init crash in template. >>> * init.c (build_vec_init): Don't perform value-init in a template. >> >> Hmm, we really shouldn't even be calling build_vec_init in a template, that >> builds up a lot of garbage that we'll throw away at the end of build_new. > > Ah, it's true that build_new will just creates a NEW_EXPR in a template and > doesn't use the result of build_new_1. Unfortunately I can't just call > build_special_member_call like we do in build_new_1 since that crashes for > array types. We should call it for strip_array_types (type). Jason ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v3] c++: Fix value-init crash in template [PR93676] 2020-02-20 0:13 ` Jason Merrill @ 2020-02-20 16:52 ` Marek Polacek 2020-02-24 22:16 ` Jason Merrill 0 siblings, 1 reply; 11+ messages in thread From: Marek Polacek @ 2020-02-20 16:52 UTC (permalink / raw) To: Jason Merrill; +Cc: GCC Patches On Thu, Feb 20, 2020 at 12:13:07AM +0000, Jason Merrill wrote: > On 2/19/20 10:15 PM, Marek Polacek wrote: > > On Fri, Feb 14, 2020 at 12:24:30AM +0100, Jason Merrill wrote: > > > On 2/11/20 8:54 PM, Marek Polacek wrote: > > > > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > > > > attempt to value-initialize in build_vec_init even when there's no > > > > initializer but the type has a constexpr default constructor. But > > > > build_value_init doesn't work in templates, so I think let's avoid > > > > this scenario; we'll go to the normal build_aggr_init path then. > > > > > > > > Bootstrapped/regtested on x86_64-linux, ok for trunk and branches? > > > > > > > > PR c++/93676 - value-init crash in template. > > > > * init.c (build_vec_init): Don't perform value-init in a template. > > > > > > Hmm, we really shouldn't even be calling build_vec_init in a template, that > > > builds up a lot of garbage that we'll throw away at the end of build_new. > > > > Ah, it's true that build_new will just creates a NEW_EXPR in a template and > > doesn't use the result of build_new_1. Unfortunately I can't just call > > build_special_member_call like we do in build_new_1 since that crashes for > > array types. > > We should call it for strip_array_types (type). Since build_special_member_call takes an expression we'd have to modify its type which I think is not pretty, but it works. Is this along the lines you had in mind? I think I still like the v1 patch best but if you're fine with the following, then am I. -- >8 -- Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we attempt to value-initialize in build_vec_init even when there's no initializer but the type has a constexpr default constructor. But build_value_init doesn't work in templates, and build_vec_init creates a lot of garbage that would not be used anyway, so don't call it in a template. PR c++/93676 - value-init crash in template. * init.c (build_new_1): Don't call build_vec_init in a template. * g++.dg/cpp0x/nsdmi-template19.C: New test. --- gcc/cp/init.c | 6 +++++- gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ 2 files changed, 18 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C diff --git a/gcc/cp/init.c b/gcc/cp/init.c index d480660445e..c60f332313a 100644 --- a/gcc/cp/init.c +++ b/gcc/cp/init.c @@ -3511,13 +3511,17 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, explicit_value_init_p = true; } - if (processing_template_decl && explicit_value_init_p) + if (processing_template_decl) { /* build_value_init doesn't work in templates, and we don't need the initializer anyway since we're going to throw it away and rebuild it at instantiation time, so just build up a single constructor call to get any appropriate diagnostics. */ init_expr = cp_build_fold_indirect_ref (data_addr); + /* Avoid an ICE when converting to a base in build_simple_base_path. + We'll throw this all away anyway, and build_new will create + a NEW_EXPR. */ + TREE_TYPE (init_expr) = strip_array_types (TREE_TYPE (init_expr)); if (type_build_ctor_call (elt_type)) init_expr = build_special_member_call (init_expr, complete_ctor_identifier, diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C new file mode 100644 index 00000000000..f3e2cb87fd6 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C @@ -0,0 +1,13 @@ +// PR c++/93676 - value-init crash in template. +// { dg-do compile { target c++11 } } + +struct P { + int x = 0; +}; + +template<class T> +struct S { + S() { new P[2][2]; } +}; + +S<int> s; base-commit: 4be779f59b04947324889b7e1488fb9a68c81d53 -- Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v3] c++: Fix value-init crash in template [PR93676] 2020-02-20 16:52 ` [PATCH v3] " Marek Polacek @ 2020-02-24 22:16 ` Jason Merrill 2020-02-25 17:53 ` [PATCH v4] " Marek Polacek 0 siblings, 1 reply; 11+ messages in thread From: Jason Merrill @ 2020-02-24 22:16 UTC (permalink / raw) To: Marek Polacek; +Cc: GCC Patches On 2/20/20 11:52 AM, Marek Polacek wrote: > On Thu, Feb 20, 2020 at 12:13:07AM +0000, Jason Merrill wrote: >> On 2/19/20 10:15 PM, Marek Polacek wrote: >>> On Fri, Feb 14, 2020 at 12:24:30AM +0100, Jason Merrill wrote: >>>> On 2/11/20 8:54 PM, Marek Polacek wrote: >>>>> Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we >>>>> attempt to value-initialize in build_vec_init even when there's no >>>>> initializer but the type has a constexpr default constructor. But >>>>> build_value_init doesn't work in templates, so I think let's avoid >>>>> this scenario; we'll go to the normal build_aggr_init path then. >>>>> >>>>> Bootstrapped/regtested on x86_64-linux, ok for trunk and branches? >>>>> >>>>> PR c++/93676 - value-init crash in template. >>>>> * init.c (build_vec_init): Don't perform value-init in a template. >>>> >>>> Hmm, we really shouldn't even be calling build_vec_init in a template, that >>>> builds up a lot of garbage that we'll throw away at the end of build_new. >>> >>> Ah, it's true that build_new will just creates a NEW_EXPR in a template and >>> doesn't use the result of build_new_1. Unfortunately I can't just call >>> build_special_member_call like we do in build_new_1 since that crashes for >>> array types. >> >> We should call it for strip_array_types (type). > > Since build_special_member_call takes an expression we'd have to modify > its type which I think is not pretty, but it works. Is this along the > lines you had in mind? > I think I still like the v1 patch best but if you're fine with the > following, then am I. > > -- >8 -- > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > attempt to value-initialize in build_vec_init even when there's no > initializer but the type has a constexpr default constructor. But > build_value_init doesn't work in templates, and build_vec_init > creates a lot of garbage that would not be used anyway, so don't > call it in a template. > > PR c++/93676 - value-init crash in template. > * init.c (build_new_1): Don't call build_vec_init in a template. > > * g++.dg/cpp0x/nsdmi-template19.C: New test. > --- > gcc/cp/init.c | 6 +++++- > gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ > 2 files changed, 18 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > > diff --git a/gcc/cp/init.c b/gcc/cp/init.c > index d480660445e..c60f332313a 100644 > --- a/gcc/cp/init.c > +++ b/gcc/cp/init.c > @@ -3511,13 +3511,17 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, > explicit_value_init_p = true; > } > > - if (processing_template_decl && explicit_value_init_p) > + if (processing_template_decl) > { > /* build_value_init doesn't work in templates, and we don't need > the initializer anyway since we're going to throw it away and > rebuild it at instantiation time, so just build up a single > constructor call to get any appropriate diagnostics. */ > init_expr = cp_build_fold_indirect_ref (data_addr); > + /* Avoid an ICE when converting to a base in build_simple_base_path. > + We'll throw this all away anyway, and build_new will create > + a NEW_EXPR. */ > + TREE_TYPE (init_expr) = strip_array_types (TREE_TYPE (init_expr)); instead of this, how about casting data_addr to elt_type* before cp_build_fold_indirect_ref? Jason ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v4] c++: Fix value-init crash in template [PR93676] 2020-02-24 22:16 ` Jason Merrill @ 2020-02-25 17:53 ` Marek Polacek 2020-02-25 18:27 ` Jason Merrill 0 siblings, 1 reply; 11+ messages in thread From: Marek Polacek @ 2020-02-25 17:53 UTC (permalink / raw) To: Jason Merrill; +Cc: GCC Patches On Mon, Feb 24, 2020 at 05:15:45PM -0500, Jason Merrill wrote: > On 2/20/20 11:52 AM, Marek Polacek wrote: > > On Thu, Feb 20, 2020 at 12:13:07AM +0000, Jason Merrill wrote: > > > On 2/19/20 10:15 PM, Marek Polacek wrote: > > > > On Fri, Feb 14, 2020 at 12:24:30AM +0100, Jason Merrill wrote: > > > > > On 2/11/20 8:54 PM, Marek Polacek wrote: > > > > > > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > > > > > > attempt to value-initialize in build_vec_init even when there's no > > > > > > initializer but the type has a constexpr default constructor. But > > > > > > build_value_init doesn't work in templates, so I think let's avoid > > > > > > this scenario; we'll go to the normal build_aggr_init path then. > > > > > > > > > > > > Bootstrapped/regtested on x86_64-linux, ok for trunk and branches? > > > > > > > > > > > > PR c++/93676 - value-init crash in template. > > > > > > * init.c (build_vec_init): Don't perform value-init in a template. > > > > > > > > > > Hmm, we really shouldn't even be calling build_vec_init in a template, that > > > > > builds up a lot of garbage that we'll throw away at the end of build_new. > > > > > > > > Ah, it's true that build_new will just creates a NEW_EXPR in a template and > > > > doesn't use the result of build_new_1. Unfortunately I can't just call > > > > build_special_member_call like we do in build_new_1 since that crashes for > > > > array types. > > > > > > We should call it for strip_array_types (type). > > > > Since build_special_member_call takes an expression we'd have to modify > > its type which I think is not pretty, but it works. Is this along the > > lines you had in mind? > > > > > I think I still like the v1 patch best but if you're fine with the > > following, then am I. > > > > -- >8 -- > > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > > attempt to value-initialize in build_vec_init even when there's no > > initializer but the type has a constexpr default constructor. But > > build_value_init doesn't work in templates, and build_vec_init > > creates a lot of garbage that would not be used anyway, so don't > > call it in a template. > > > > PR c++/93676 - value-init crash in template. > > * init.c (build_new_1): Don't call build_vec_init in a template. > > > > * g++.dg/cpp0x/nsdmi-template19.C: New test. > > --- > > gcc/cp/init.c | 6 +++++- > > gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ > > 2 files changed, 18 insertions(+), 1 deletion(-) > > create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > > > > diff --git a/gcc/cp/init.c b/gcc/cp/init.c > > index d480660445e..c60f332313a 100644 > > --- a/gcc/cp/init.c > > +++ b/gcc/cp/init.c > > @@ -3511,13 +3511,17 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, > > explicit_value_init_p = true; > > } > > - if (processing_template_decl && explicit_value_init_p) > > + if (processing_template_decl) > > { > > /* build_value_init doesn't work in templates, and we don't need > > the initializer anyway since we're going to throw it away and > > rebuild it at instantiation time, so just build up a single > > constructor call to get any appropriate diagnostics. */ > > init_expr = cp_build_fold_indirect_ref (data_addr); > > + /* Avoid an ICE when converting to a base in build_simple_base_path. > > + We'll throw this all away anyway, and build_new will create > > + a NEW_EXPR. */ > > + TREE_TYPE (init_expr) = strip_array_types (TREE_TYPE (init_expr)); > > instead of this, how about casting data_addr to elt_type* before > cp_build_fold_indirect_ref? That seems to work, thanks! Bootstrapped/regtested on x86_64-linux, ok for trunk? -- >8 -- Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we attempt to value-initialize in build_vec_init even when there's no initializer but the type has a constexpr default constructor. But build_value_init doesn't work in templates, and build_vec_init creates a lot of garbage that would not be used anyway, so don't call it in a template. PR c++/93676 - value-init crash in template. * init.c (build_new_1): Don't call build_vec_init in a template. * g++.dg/cpp0x/nsdmi-template19.C: New test. --- gcc/cp/init.c | 6 +++++- gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ 2 files changed, 18 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C diff --git a/gcc/cp/init.c b/gcc/cp/init.c index d480660445e..31a130422af 100644 --- a/gcc/cp/init.c +++ b/gcc/cp/init.c @@ -3511,8 +3511,12 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, explicit_value_init_p = true; } - if (processing_template_decl && explicit_value_init_p) + if (processing_template_decl) { + /* Avoid an ICE when converting to a base in build_simple_base_path. + We'll throw this all away anyway, and build_new will create + a NEW_EXPR. */ + data_addr = build_nop (build_pointer_type (elt_type), data_addr); /* build_value_init doesn't work in templates, and we don't need the initializer anyway since we're going to throw it away and rebuild it at instantiation time, so just build up a single diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C new file mode 100644 index 00000000000..f3e2cb87fd6 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C @@ -0,0 +1,13 @@ +// PR c++/93676 - value-init crash in template. +// { dg-do compile { target c++11 } } + +struct P { + int x = 0; +}; + +template<class T> +struct S { + S() { new P[2][2]; } +}; + +S<int> s; base-commit: a71f2193d0df71a86c4743aab22891bb0003112e -- Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v4] c++: Fix value-init crash in template [PR93676] 2020-02-25 17:53 ` [PATCH v4] " Marek Polacek @ 2020-02-25 18:27 ` Jason Merrill 2020-02-25 18:55 ` [PATCH v5] " Marek Polacek 0 siblings, 1 reply; 11+ messages in thread From: Jason Merrill @ 2020-02-25 18:27 UTC (permalink / raw) To: Marek Polacek; +Cc: GCC Patches On 2/25/20 12:52 PM, Marek Polacek wrote: > On Mon, Feb 24, 2020 at 05:15:45PM -0500, Jason Merrill wrote: >> On 2/20/20 11:52 AM, Marek Polacek wrote: >>> On Thu, Feb 20, 2020 at 12:13:07AM +0000, Jason Merrill wrote: >>>> On 2/19/20 10:15 PM, Marek Polacek wrote: >>>>> On Fri, Feb 14, 2020 at 12:24:30AM +0100, Jason Merrill wrote: >>>>>> On 2/11/20 8:54 PM, Marek Polacek wrote: >>>>>>> Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we >>>>>>> attempt to value-initialize in build_vec_init even when there's no >>>>>>> initializer but the type has a constexpr default constructor. But >>>>>>> build_value_init doesn't work in templates, so I think let's avoid >>>>>>> this scenario; we'll go to the normal build_aggr_init path then. >>>>>>> >>>>>>> Bootstrapped/regtested on x86_64-linux, ok for trunk and branches? >>>>>>> >>>>>>> PR c++/93676 - value-init crash in template. >>>>>>> * init.c (build_vec_init): Don't perform value-init in a template. >>>>>> >>>>>> Hmm, we really shouldn't even be calling build_vec_init in a template, that >>>>>> builds up a lot of garbage that we'll throw away at the end of build_new. >>>>> >>>>> Ah, it's true that build_new will just creates a NEW_EXPR in a template and >>>>> doesn't use the result of build_new_1. Unfortunately I can't just call >>>>> build_special_member_call like we do in build_new_1 since that crashes for >>>>> array types. >>>> >>>> We should call it for strip_array_types (type). >>> >>> Since build_special_member_call takes an expression we'd have to modify >>> its type which I think is not pretty, but it works. Is this along the >>> lines you had in mind? >> >> >> >>> I think I still like the v1 patch best but if you're fine with the >>> following, then am I. >>> >>> -- >8 -- >>> Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we >>> attempt to value-initialize in build_vec_init even when there's no >>> initializer but the type has a constexpr default constructor. But >>> build_value_init doesn't work in templates, and build_vec_init >>> creates a lot of garbage that would not be used anyway, so don't >>> call it in a template. >>> >>> PR c++/93676 - value-init crash in template. >>> * init.c (build_new_1): Don't call build_vec_init in a template. >>> >>> * g++.dg/cpp0x/nsdmi-template19.C: New test. >>> --- >>> gcc/cp/init.c | 6 +++++- >>> gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ >>> 2 files changed, 18 insertions(+), 1 deletion(-) >>> create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C >>> >>> diff --git a/gcc/cp/init.c b/gcc/cp/init.c >>> index d480660445e..c60f332313a 100644 >>> --- a/gcc/cp/init.c >>> +++ b/gcc/cp/init.c >>> @@ -3511,13 +3511,17 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, >>> explicit_value_init_p = true; >>> } >>> - if (processing_template_decl && explicit_value_init_p) >>> + if (processing_template_decl) >>> { >>> /* build_value_init doesn't work in templates, and we don't need >>> the initializer anyway since we're going to throw it away and >>> rebuild it at instantiation time, so just build up a single >>> constructor call to get any appropriate diagnostics. */ >>> init_expr = cp_build_fold_indirect_ref (data_addr); >>> + /* Avoid an ICE when converting to a base in build_simple_base_path. >>> + We'll throw this all away anyway, and build_new will create >>> + a NEW_EXPR. */ >>> + TREE_TYPE (init_expr) = strip_array_types (TREE_TYPE (init_expr)); >> >> instead of this, how about casting data_addr to elt_type* before >> cp_build_fold_indirect_ref? > > That seems to work, thanks! > > Bootstrapped/regtested on x86_64-linux, ok for trunk? > > -- >8 -- > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > attempt to value-initialize in build_vec_init even when there's no > initializer but the type has a constexpr default constructor. But > build_value_init doesn't work in templates, and build_vec_init > creates a lot of garbage that would not be used anyway, so don't > call it in a template. > > PR c++/93676 - value-init crash in template. > * init.c (build_new_1): Don't call build_vec_init in a template. > > * g++.dg/cpp0x/nsdmi-template19.C: New test. > --- > gcc/cp/init.c | 6 +++++- > gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ > 2 files changed, 18 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > > diff --git a/gcc/cp/init.c b/gcc/cp/init.c > index d480660445e..31a130422af 100644 > --- a/gcc/cp/init.c > +++ b/gcc/cp/init.c > @@ -3511,8 +3511,12 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, > explicit_value_init_p = true; > } > > - if (processing_template_decl && explicit_value_init_p) > + if (processing_template_decl) > { > + /* Avoid an ICE when converting to a base in build_simple_base_path. > + We'll throw this all away anyway, and build_new will create > + a NEW_EXPR. */ > + data_addr = build_nop (build_pointer_type (elt_type), data_addr); Let's use a new local variable instead of changing data_addr, which following code expects to still have its old type. And as a minor tweak, data_addr might already have the right type, so let's use fold_convert like other places in the function. > /* build_value_init doesn't work in templates, and we don't need > the initializer anyway since we're going to throw it away and > rebuild it at instantiation time, so just build up a single > diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > new file mode 100644 > index 00000000000..f3e2cb87fd6 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > @@ -0,0 +1,13 @@ > +// PR c++/93676 - value-init crash in template. > +// { dg-do compile { target c++11 } } > + > +struct P { > + int x = 0; > +}; > + > +template<class T> > +struct S { > + S() { new P[2][2]; } > +}; > + > +S<int> s; > > base-commit: a71f2193d0df71a86c4743aab22891bb0003112e > ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v5] c++: Fix value-init crash in template [PR93676] 2020-02-25 18:27 ` Jason Merrill @ 2020-02-25 18:55 ` Marek Polacek 2020-02-25 19:34 ` Marek Polacek 2020-02-26 4:26 ` Jason Merrill 0 siblings, 2 replies; 11+ messages in thread From: Marek Polacek @ 2020-02-25 18:55 UTC (permalink / raw) To: Jason Merrill; +Cc: GCC Patches On Tue, Feb 25, 2020 at 01:27:12PM -0500, Jason Merrill wrote: > On 2/25/20 12:52 PM, Marek Polacek wrote: > > On Mon, Feb 24, 2020 at 05:15:45PM -0500, Jason Merrill wrote: > > > On 2/20/20 11:52 AM, Marek Polacek wrote: > > > > On Thu, Feb 20, 2020 at 12:13:07AM +0000, Jason Merrill wrote: > > > > > On 2/19/20 10:15 PM, Marek Polacek wrote: > > > > > > On Fri, Feb 14, 2020 at 12:24:30AM +0100, Jason Merrill wrote: > > > > > > > On 2/11/20 8:54 PM, Marek Polacek wrote: > > > > > > > > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > > > > > > > > attempt to value-initialize in build_vec_init even when there's no > > > > > > > > initializer but the type has a constexpr default constructor. But > > > > > > > > build_value_init doesn't work in templates, so I think let's avoid > > > > > > > > this scenario; we'll go to the normal build_aggr_init path then. > > > > > > > > > > > > > > > > Bootstrapped/regtested on x86_64-linux, ok for trunk and branches? > > > > > > > > > > > > > > > > PR c++/93676 - value-init crash in template. > > > > > > > > * init.c (build_vec_init): Don't perform value-init in a template. > > > > > > > > > > > > > > Hmm, we really shouldn't even be calling build_vec_init in a template, that > > > > > > > builds up a lot of garbage that we'll throw away at the end of build_new. > > > > > > > > > > > > Ah, it's true that build_new will just creates a NEW_EXPR in a template and > > > > > > doesn't use the result of build_new_1. Unfortunately I can't just call > > > > > > build_special_member_call like we do in build_new_1 since that crashes for > > > > > > array types. > > > > > > > > > > We should call it for strip_array_types (type). > > > > > > > > Since build_special_member_call takes an expression we'd have to modify > > > > its type which I think is not pretty, but it works. Is this along the > > > > lines you had in mind? > > > > > > > > > > > > > I think I still like the v1 patch best but if you're fine with the > > > > following, then am I. > > > > > > > > -- >8 -- > > > > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > > > > attempt to value-initialize in build_vec_init even when there's no > > > > initializer but the type has a constexpr default constructor. But > > > > build_value_init doesn't work in templates, and build_vec_init > > > > creates a lot of garbage that would not be used anyway, so don't > > > > call it in a template. > > > > > > > > PR c++/93676 - value-init crash in template. > > > > * init.c (build_new_1): Don't call build_vec_init in a template. > > > > > > > > * g++.dg/cpp0x/nsdmi-template19.C: New test. > > > > --- > > > > gcc/cp/init.c | 6 +++++- > > > > gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ > > > > 2 files changed, 18 insertions(+), 1 deletion(-) > > > > create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > > > > > > > > diff --git a/gcc/cp/init.c b/gcc/cp/init.c > > > > index d480660445e..c60f332313a 100644 > > > > --- a/gcc/cp/init.c > > > > +++ b/gcc/cp/init.c > > > > @@ -3511,13 +3511,17 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, > > > > explicit_value_init_p = true; > > > > } > > > > - if (processing_template_decl && explicit_value_init_p) > > > > + if (processing_template_decl) > > > > { > > > > /* build_value_init doesn't work in templates, and we don't need > > > > the initializer anyway since we're going to throw it away and > > > > rebuild it at instantiation time, so just build up a single > > > > constructor call to get any appropriate diagnostics. */ > > > > init_expr = cp_build_fold_indirect_ref (data_addr); > > > > + /* Avoid an ICE when converting to a base in build_simple_base_path. > > > > + We'll throw this all away anyway, and build_new will create > > > > + a NEW_EXPR. */ > > > > + TREE_TYPE (init_expr) = strip_array_types (TREE_TYPE (init_expr)); > > > > > > instead of this, how about casting data_addr to elt_type* before > > > cp_build_fold_indirect_ref? Gotcha. I'm testing the following, OK for 8/9/10 if it passes? -- >8 -- Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we attempt to value-initialize in build_vec_init even when there's no initializer but the type has a constexpr default constructor. But build_value_init doesn't work in templates, and build_vec_init creates a lot of garbage that would not be used anyway, so don't call it in a template. PR c++/93676 - value-init crash in template. * init.c (build_new_1): Don't call build_vec_init in a template. * g++.dg/cpp0x/nsdmi-template19.C: New test. --- gcc/cp/init.c | 8 ++++++-- gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ 2 files changed, 19 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C diff --git a/gcc/cp/init.c b/gcc/cp/init.c index d480660445e..61ed3aa7e93 100644 --- a/gcc/cp/init.c +++ b/gcc/cp/init.c @@ -3511,13 +3511,17 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, explicit_value_init_p = true; } - if (processing_template_decl && explicit_value_init_p) + if (processing_template_decl) { + /* Avoid an ICE when converting to a base in build_simple_base_path. + We'll throw this all away anyway, and build_new will create + a NEW_EXPR. */ + tree t = fold_convert (build_pointer_type (elt_type), data_addr); /* build_value_init doesn't work in templates, and we don't need the initializer anyway since we're going to throw it away and rebuild it at instantiation time, so just build up a single constructor call to get any appropriate diagnostics. */ - init_expr = cp_build_fold_indirect_ref (data_addr); + init_expr = cp_build_fold_indirect_ref (t); if (type_build_ctor_call (elt_type)) init_expr = build_special_member_call (init_expr, complete_ctor_identifier, diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C new file mode 100644 index 00000000000..f3e2cb87fd6 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C @@ -0,0 +1,13 @@ +// PR c++/93676 - value-init crash in template. +// { dg-do compile { target c++11 } } + +struct P { + int x = 0; +}; + +template<class T> +struct S { + S() { new P[2][2]; } +}; + +S<int> s; base-commit: a71f2193d0df71a86c4743aab22891bb0003112e -- Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v5] c++: Fix value-init crash in template [PR93676] 2020-02-25 18:55 ` [PATCH v5] " Marek Polacek @ 2020-02-25 19:34 ` Marek Polacek 2020-02-26 4:26 ` Jason Merrill 1 sibling, 0 replies; 11+ messages in thread From: Marek Polacek @ 2020-02-25 19:34 UTC (permalink / raw) To: Jason Merrill; +Cc: GCC Patches On Tue, Feb 25, 2020 at 01:55:24PM -0500, Marek Polacek wrote: > On Tue, Feb 25, 2020 at 01:27:12PM -0500, Jason Merrill wrote: > > On 2/25/20 12:52 PM, Marek Polacek wrote: > > > On Mon, Feb 24, 2020 at 05:15:45PM -0500, Jason Merrill wrote: > > > > On 2/20/20 11:52 AM, Marek Polacek wrote: > > > > > On Thu, Feb 20, 2020 at 12:13:07AM +0000, Jason Merrill wrote: > > > > > > On 2/19/20 10:15 PM, Marek Polacek wrote: > > > > > > > On Fri, Feb 14, 2020 at 12:24:30AM +0100, Jason Merrill wrote: > > > > > > > > On 2/11/20 8:54 PM, Marek Polacek wrote: > > > > > > > > > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > > > > > > > > > attempt to value-initialize in build_vec_init even when there's no > > > > > > > > > initializer but the type has a constexpr default constructor. But > > > > > > > > > build_value_init doesn't work in templates, so I think let's avoid > > > > > > > > > this scenario; we'll go to the normal build_aggr_init path then. > > > > > > > > > > > > > > > > > > Bootstrapped/regtested on x86_64-linux, ok for trunk and branches? > > > > > > > > > > > > > > > > > > PR c++/93676 - value-init crash in template. > > > > > > > > > * init.c (build_vec_init): Don't perform value-init in a template. > > > > > > > > > > > > > > > > Hmm, we really shouldn't even be calling build_vec_init in a template, that > > > > > > > > builds up a lot of garbage that we'll throw away at the end of build_new. > > > > > > > > > > > > > > Ah, it's true that build_new will just creates a NEW_EXPR in a template and > > > > > > > doesn't use the result of build_new_1. Unfortunately I can't just call > > > > > > > build_special_member_call like we do in build_new_1 since that crashes for > > > > > > > array types. > > > > > > > > > > > > We should call it for strip_array_types (type). > > > > > > > > > > Since build_special_member_call takes an expression we'd have to modify > > > > > its type which I think is not pretty, but it works. Is this along the > > > > > lines you had in mind? > > > > > > > > > > > > > > > > > I think I still like the v1 patch best but if you're fine with the > > > > > following, then am I. > > > > > > > > > > -- >8 -- > > > > > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > > > > > attempt to value-initialize in build_vec_init even when there's no > > > > > initializer but the type has a constexpr default constructor. But > > > > > build_value_init doesn't work in templates, and build_vec_init > > > > > creates a lot of garbage that would not be used anyway, so don't > > > > > call it in a template. > > > > > > > > > > PR c++/93676 - value-init crash in template. > > > > > * init.c (build_new_1): Don't call build_vec_init in a template. > > > > > > > > > > * g++.dg/cpp0x/nsdmi-template19.C: New test. > > > > > --- > > > > > gcc/cp/init.c | 6 +++++- > > > > > gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ > > > > > 2 files changed, 18 insertions(+), 1 deletion(-) > > > > > create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > > > > > > > > > > diff --git a/gcc/cp/init.c b/gcc/cp/init.c > > > > > index d480660445e..c60f332313a 100644 > > > > > --- a/gcc/cp/init.c > > > > > +++ b/gcc/cp/init.c > > > > > @@ -3511,13 +3511,17 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, > > > > > explicit_value_init_p = true; > > > > > } > > > > > - if (processing_template_decl && explicit_value_init_p) > > > > > + if (processing_template_decl) > > > > > { > > > > > /* build_value_init doesn't work in templates, and we don't need > > > > > the initializer anyway since we're going to throw it away and > > > > > rebuild it at instantiation time, so just build up a single > > > > > constructor call to get any appropriate diagnostics. */ > > > > > init_expr = cp_build_fold_indirect_ref (data_addr); > > > > > + /* Avoid an ICE when converting to a base in build_simple_base_path. > > > > > + We'll throw this all away anyway, and build_new will create > > > > > + a NEW_EXPR. */ > > > > > + TREE_TYPE (init_expr) = strip_array_types (TREE_TYPE (init_expr)); > > > > > > > > instead of this, how about casting data_addr to elt_type* before > > > > cp_build_fold_indirect_ref? > > Gotcha. I'm testing the following, OK for 8/9/10 if it passes? Which it did. > -- >8 -- > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > attempt to value-initialize in build_vec_init even when there's no > initializer but the type has a constexpr default constructor. But > build_value_init doesn't work in templates, and build_vec_init > creates a lot of garbage that would not be used anyway, so don't > call it in a template. > > PR c++/93676 - value-init crash in template. > * init.c (build_new_1): Don't call build_vec_init in a template. > > * g++.dg/cpp0x/nsdmi-template19.C: New test. > --- > gcc/cp/init.c | 8 ++++++-- > gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ > 2 files changed, 19 insertions(+), 2 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > > diff --git a/gcc/cp/init.c b/gcc/cp/init.c > index d480660445e..61ed3aa7e93 100644 > --- a/gcc/cp/init.c > +++ b/gcc/cp/init.c > @@ -3511,13 +3511,17 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, > explicit_value_init_p = true; > } > > - if (processing_template_decl && explicit_value_init_p) > + if (processing_template_decl) > { > + /* Avoid an ICE when converting to a base in build_simple_base_path. > + We'll throw this all away anyway, and build_new will create > + a NEW_EXPR. */ > + tree t = fold_convert (build_pointer_type (elt_type), data_addr); > /* build_value_init doesn't work in templates, and we don't need > the initializer anyway since we're going to throw it away and > rebuild it at instantiation time, so just build up a single > constructor call to get any appropriate diagnostics. */ > - init_expr = cp_build_fold_indirect_ref (data_addr); > + init_expr = cp_build_fold_indirect_ref (t); > if (type_build_ctor_call (elt_type)) > init_expr = build_special_member_call (init_expr, > complete_ctor_identifier, > diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > new file mode 100644 > index 00000000000..f3e2cb87fd6 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > @@ -0,0 +1,13 @@ > +// PR c++/93676 - value-init crash in template. > +// { dg-do compile { target c++11 } } > + > +struct P { > + int x = 0; > +}; > + > +template<class T> > +struct S { > + S() { new P[2][2]; } > +}; > + > +S<int> s; > > base-commit: a71f2193d0df71a86c4743aab22891bb0003112e > -- > Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA > Marek ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v5] c++: Fix value-init crash in template [PR93676] 2020-02-25 18:55 ` [PATCH v5] " Marek Polacek 2020-02-25 19:34 ` Marek Polacek @ 2020-02-26 4:26 ` Jason Merrill 1 sibling, 0 replies; 11+ messages in thread From: Jason Merrill @ 2020-02-26 4:26 UTC (permalink / raw) To: Marek Polacek; +Cc: GCC Patches On 2/25/20 1:55 PM, Marek Polacek wrote: > On Tue, Feb 25, 2020 at 01:27:12PM -0500, Jason Merrill wrote: >> On 2/25/20 12:52 PM, Marek Polacek wrote: >>> On Mon, Feb 24, 2020 at 05:15:45PM -0500, Jason Merrill wrote: >>>> On 2/20/20 11:52 AM, Marek Polacek wrote: >>>>> On Thu, Feb 20, 2020 at 12:13:07AM +0000, Jason Merrill wrote: >>>>>> On 2/19/20 10:15 PM, Marek Polacek wrote: >>>>>>> On Fri, Feb 14, 2020 at 12:24:30AM +0100, Jason Merrill wrote: >>>>>>>> On 2/11/20 8:54 PM, Marek Polacek wrote: >>>>>>>>> Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we >>>>>>>>> attempt to value-initialize in build_vec_init even when there's no >>>>>>>>> initializer but the type has a constexpr default constructor. But >>>>>>>>> build_value_init doesn't work in templates, so I think let's avoid >>>>>>>>> this scenario; we'll go to the normal build_aggr_init path then. >>>>>>>>> >>>>>>>>> Bootstrapped/regtested on x86_64-linux, ok for trunk and branches? >>>>>>>>> >>>>>>>>> PR c++/93676 - value-init crash in template. >>>>>>>>> * init.c (build_vec_init): Don't perform value-init in a template. >>>>>>>> >>>>>>>> Hmm, we really shouldn't even be calling build_vec_init in a template, that >>>>>>>> builds up a lot of garbage that we'll throw away at the end of build_new. >>>>>>> >>>>>>> Ah, it's true that build_new will just creates a NEW_EXPR in a template and >>>>>>> doesn't use the result of build_new_1. Unfortunately I can't just call >>>>>>> build_special_member_call like we do in build_new_1 since that crashes for >>>>>>> array types. >>>>>> >>>>>> We should call it for strip_array_types (type). >>>>> >>>>> Since build_special_member_call takes an expression we'd have to modify >>>>> its type which I think is not pretty, but it works. Is this along the >>>>> lines you had in mind? >>>> >>>> >>>> >>>>> I think I still like the v1 patch best but if you're fine with the >>>>> following, then am I. >>>>> >>>>> -- >8 -- >>>>> Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we >>>>> attempt to value-initialize in build_vec_init even when there's no >>>>> initializer but the type has a constexpr default constructor. But >>>>> build_value_init doesn't work in templates, and build_vec_init >>>>> creates a lot of garbage that would not be used anyway, so don't >>>>> call it in a template. >>>>> >>>>> PR c++/93676 - value-init crash in template. >>>>> * init.c (build_new_1): Don't call build_vec_init in a template. >>>>> >>>>> * g++.dg/cpp0x/nsdmi-template19.C: New test. >>>>> --- >>>>> gcc/cp/init.c | 6 +++++- >>>>> gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ >>>>> 2 files changed, 18 insertions(+), 1 deletion(-) >>>>> create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C >>>>> >>>>> diff --git a/gcc/cp/init.c b/gcc/cp/init.c >>>>> index d480660445e..c60f332313a 100644 >>>>> --- a/gcc/cp/init.c >>>>> +++ b/gcc/cp/init.c >>>>> @@ -3511,13 +3511,17 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, >>>>> explicit_value_init_p = true; >>>>> } >>>>> - if (processing_template_decl && explicit_value_init_p) >>>>> + if (processing_template_decl) >>>>> { >>>>> /* build_value_init doesn't work in templates, and we don't need >>>>> the initializer anyway since we're going to throw it away and >>>>> rebuild it at instantiation time, so just build up a single >>>>> constructor call to get any appropriate diagnostics. */ >>>>> init_expr = cp_build_fold_indirect_ref (data_addr); >>>>> + /* Avoid an ICE when converting to a base in build_simple_base_path. >>>>> + We'll throw this all away anyway, and build_new will create >>>>> + a NEW_EXPR. */ >>>>> + TREE_TYPE (init_expr) = strip_array_types (TREE_TYPE (init_expr)); >>>> >>>> instead of this, how about casting data_addr to elt_type* before >>>> cp_build_fold_indirect_ref? > > Gotcha. I'm testing the following, OK for 8/9/10 if it passes? OK. > > -- >8 -- > Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we > attempt to value-initialize in build_vec_init even when there's no > initializer but the type has a constexpr default constructor. But > build_value_init doesn't work in templates, and build_vec_init > creates a lot of garbage that would not be used anyway, so don't > call it in a template. > > PR c++/93676 - value-init crash in template. > * init.c (build_new_1): Don't call build_vec_init in a template. > > * g++.dg/cpp0x/nsdmi-template19.C: New test. > --- > gcc/cp/init.c | 8 ++++++-- > gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++ > 2 files changed, 19 insertions(+), 2 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > > diff --git a/gcc/cp/init.c b/gcc/cp/init.c > index d480660445e..61ed3aa7e93 100644 > --- a/gcc/cp/init.c > +++ b/gcc/cp/init.c > @@ -3511,13 +3511,17 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts, > explicit_value_init_p = true; > } > > - if (processing_template_decl && explicit_value_init_p) > + if (processing_template_decl) > { > + /* Avoid an ICE when converting to a base in build_simple_base_path. > + We'll throw this all away anyway, and build_new will create > + a NEW_EXPR. */ > + tree t = fold_convert (build_pointer_type (elt_type), data_addr); > /* build_value_init doesn't work in templates, and we don't need > the initializer anyway since we're going to throw it away and > rebuild it at instantiation time, so just build up a single > constructor call to get any appropriate diagnostics. */ > - init_expr = cp_build_fold_indirect_ref (data_addr); > + init_expr = cp_build_fold_indirect_ref (t); > if (type_build_ctor_call (elt_type)) > init_expr = build_special_member_call (init_expr, > complete_ctor_identifier, > diff --git a/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > new file mode 100644 > index 00000000000..f3e2cb87fd6 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C > @@ -0,0 +1,13 @@ > +// PR c++/93676 - value-init crash in template. > +// { dg-do compile { target c++11 } } > + > +struct P { > + int x = 0; > +}; > + > +template<class T> > +struct S { > + S() { new P[2][2]; } > +}; > + > +S<int> s; > > base-commit: a71f2193d0df71a86c4743aab22891bb0003112e > ^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2020-02-26 4:26 UTC | newest] Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-02-11 19:55 [PATCH] c++: Fix value-init crash in template [PR93676] Marek Polacek 2020-02-13 23:24 ` Jason Merrill 2020-02-19 21:15 ` [PATCH v2] " Marek Polacek 2020-02-20 0:13 ` Jason Merrill 2020-02-20 16:52 ` [PATCH v3] " Marek Polacek 2020-02-24 22:16 ` Jason Merrill 2020-02-25 17:53 ` [PATCH v4] " Marek Polacek 2020-02-25 18:27 ` Jason Merrill 2020-02-25 18:55 ` [PATCH v5] " Marek Polacek 2020-02-25 19:34 ` Marek Polacek 2020-02-26 4:26 ` Jason Merrill
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