On 2/18/21 7:15 AM, Martin Liška wrote:
We crash when target attribute get_function_versions_dispatcher is called for a function that is not registered in call graph. This fixes that by emitting a new error.Patch can bootstrap on x86_64-linux-gnu and survives regression tests. Ready to be installed? Thanks, Martin gcc/cp/ChangeLog: PR c++/99108 * call.c (get_function_version_dispatcher): Do not parse target attribute for a function with a missing declaration. gcc/testsuite/ChangeLog: PR c++/99108 * g++.target/i386/pr99108.C: New test. --- gcc/cp/call.c | 8 +++++++- gcc/testsuite/g++.target/i386/pr99108.C | 18 ++++++++++++++++++ 2 files changed, 25 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.target/i386/pr99108.C diff --git a/gcc/cp/call.c b/gcc/cp/call.c index 186feef6fe3..844853e504e 100644 --- a/gcc/cp/call.c +++ b/gcc/cp/call.c @@ -8386,8 +8386,14 @@ get_function_version_dispatcher (tree fn) && DECL_FUNCTION_VERSIONED (fn)); gcc_assert (targetm.get_function_versions_dispatcher); - dispatcher_decl = targetm.get_function_versions_dispatcher (fn); + if (cgraph_node::get (fn) == NULL) + { + error_at (DECL_SOURCE_LOCATION (fn), "missing declaration " + "for a multiversioned function");
This seems like the wrong message. The declaration isn't missing, you're using its source location for the error. Do you mean "definition"? But adding definitions earlier in the file doesn't help. And having file-scope declarations without definitions is fine.
The problem seems to be with the handling of local decls. If DECL_LOCAL_DECL_P, you need to look at DECL_LOCAL_DECL_ALIAS to find the namespace-scope decl. But then if there is no preceding namespace-scope declaration, the new decl created by push_local_extern_decl_alias doesn't have a cgraph node, either. I guess maybe_function_versions also needs to look through DECL_LOCAL_DECL_ALIAS.
+ return NULL; + } + dispatcher_decl = targetm.get_function_versions_dispatcher (fn); if (dispatcher_decl == NULL) { error_at (input_location, "use of multiversioned function "diff --git a/gcc/testsuite/g++.target/i386/pr99108.C b/gcc/testsuite/g++.target/i386/pr99108.Cnew file mode 100644 index 00000000000..b0c4ffa2688 --- /dev/null +++ b/gcc/testsuite/g++.target/i386/pr99108.C @@ -0,0 +1,18 @@ +/* PR c++/99108 */ +/* { dg-do compile { target c++20 } } */ +/* { dg-require-ifunc "" } */ + +struct A { + void foo(auto); +}; +void A::foo(auto) +{ + int f(void) __attribute__((target("default")));+ int f(void) __attribute__((target("arch=atom"))); /* { dg-error "missing declaration for a multiversioned function" } */+ int b = f(); +} +void bar(void) +{ + A c; + c.foo(7); +}
