tree-profile: Disable indirect call profiling for IFUNC resolvers

We can't profile indirect calls to IFUNC resolvers nor their callees as
it requires TLS which hasn't been set up yet when the dynamic linker is
resolving IFUNC symbols.

Add an IFUNC resolver caller marker to cgraph_node and set it if the
function is called by an IFUNC resolver.  Disable indirect call profiling
for IFUNC resolvers and their callees.

Tested with profiledbootstrap on Fedora 39/x86-64.

gcc/ChangeLog:

	PR tree-optimization/114115
	* cgraph.h (symtab_node): Add check_ifunc_callee_symtab_nodes.
	(cgraph_node): Add called_by_ifunc_resolver.
	* cgraphunit.c (symbol_table::compile): Call
	symtab_node::check_ifunc_callee_symtab_nodes.
	* symtab.c (check_ifunc_resolver): New.
	(ifunc_ref_map): Likewise.
	(is_caller_ifunc_resolver): Likewise.
	(symtab_node::check_ifunc_callee_symtab_nodes): Likewise.
	* tree-profile.c (gimple_gen_ic_func_profiler): Disable indirect
	call profiling for IFUNC resolvers and their callees.

gcc/testsuite/ChangeLog:

	PR tree-optimization/114115
	* gcc.dg/pr114115.c: New test.

(cherry picked from commit cab32bacaea268ec062b1fb4fc662d90c9d1cfce)

diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index 4a1f89920f56b685c1f33843fb86848b5847cbeb..8e6128bf25d47e2dabe5db2c0d22951b2e9d9516 100644 (file)
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -473,6 +473,9 @@ public:
      Return NULL if there's no such node.  */
   static symtab_node *get_for_asmname (const_tree asmname);
 
+  /* Check symbol table for callees of IFUNC resolvers.  */
+  static void check_ifunc_callee_symtab_nodes (void);
+
   /* Verify symbol table for internal consistency.  */
   static DEBUG_FUNCTION void verify_symtab_nodes (void);
 
@@ -883,7 +886,9 @@ struct GTY((tag ("SYMTAB_FUNCTION"))) cgraph_node : public symtab_node
       versionable (false), can_change_signature (false),
       redefined_extern_inline (false), tm_may_enter_irr (false),
       ipcp_clone (false), declare_variant_alt (false),
-      calls_declare_variant_alt (false), m_uid (uid), m_summary_id (-1)
+      calls_declare_variant_alt (false),
+      called_by_ifunc_resolver (false),
+      m_uid (uid), m_summary_id (-1)
   {}
 
   /* Remove the node from cgraph and all inline clones inlined into it.
@@ -1475,6 +1480,8 @@ struct GTY((tag ("SYMTAB_FUNCTION"))) cgraph_node : public symtab_node
   unsigned declare_variant_alt : 1;
   /* True if the function calls declare_variant_alt functions.  */
   unsigned calls_declare_variant_alt : 1;
+  /* Set if the function is called by an IFUNC resolver.  */
+  unsigned called_by_ifunc_resolver : 1;
 
 private:
   /* Unique id of the node.  */

diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index 802b01d3b977bcedfed74deb82d529f93c1a83fd..98c9a492e0030bb0c51707a69092395e16f77e6d 100644 (file)
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -2273,6 +2273,8 @@ symbol_table::compile (void)
 
   symtab_node::checking_verify_symtab_nodes ();
 
+  symtab_node::check_ifunc_callee_symtab_nodes ();
+
   timevar_push (TV_CGRAPHOPT);
   if (pre_ipa_mem_report)
     dump_memory_report ("Memory consumption before IPA");

diff --git a/gcc/symtab.c b/gcc/symtab.c
index 5530a124a9d42c8422cdfa7c939035d3824190e2..04b8283199cd7ba2c8750d72e298c67d1e8208ff 100644 (file)
--- a/gcc/symtab.c
+++ b/gcc/symtab.c
@@ -1363,6 +1363,95 @@ symtab_node::verify (void)
   timevar_pop (TV_CGRAPH_VERIFY);
 }
 
+/* Return true and set *DATA to true if NODE is an ifunc resolver.  */
+
+static bool
+check_ifunc_resolver (cgraph_node *node, void *data)
+{
+  if (node->ifunc_resolver)
+    {
+      bool *is_ifunc_resolver = (bool *) data;
+      *is_ifunc_resolver = true;
+      return true;
+    }
+  return false;
+}
+
+static auto_bitmap ifunc_ref_map;
+
+/* Return true if any caller of NODE is an ifunc resolver.  */
+
+static bool
+is_caller_ifunc_resolver (cgraph_node *node)
+{
+  bool is_ifunc_resolver = false;
+
+  for (cgraph_edge *e = node->callers; e; e = e->next_caller)
+    {
+      /* Return true if caller is known to be an IFUNC resolver.  */
+      if (e->caller->called_by_ifunc_resolver)
+       return true;
+
+      /* Check for recursive call.  */
+      if (e->caller == node)
+       continue;
+
+      /* Skip if it has been visited.  */
+      unsigned int uid = e->caller->get_uid ();
+      if (bitmap_bit_p (ifunc_ref_map, uid))
+       continue;
+      bitmap_set_bit (ifunc_ref_map, uid);
+
+      if (is_caller_ifunc_resolver (e->caller))
+       {
+         /* Return true if caller is an IFUNC resolver.  */
+         e->caller->called_by_ifunc_resolver = true;
+         return true;
+       }
+
+      /* Check if caller's alias is an IFUNC resolver.  */
+      e->caller->call_for_symbol_and_aliases (check_ifunc_resolver,
+                                             &is_ifunc_resolver,
+                                             true);
+      if (is_ifunc_resolver)
+       {
+         /* Return true if caller's alias is an IFUNC resolver.  */
+         e->caller->called_by_ifunc_resolver = true;
+         return true;
+       }
+    }
+
+  return false;
+}
+
+/* Check symbol table for callees of IFUNC resolvers.  */
+
+void
+symtab_node::check_ifunc_callee_symtab_nodes (void)
+{
+  symtab_node *node;
+
+  FOR_EACH_SYMBOL (node)
+    {
+      cgraph_node *cnode = dyn_cast <cgraph_node *> (node);
+      if (!cnode)
+       continue;
+
+      unsigned int uid = cnode->get_uid ();
+      if (bitmap_bit_p (ifunc_ref_map, uid))
+       continue;
+      bitmap_set_bit (ifunc_ref_map, uid);
+
+      bool is_ifunc_resolver = false;
+      cnode->call_for_symbol_and_aliases (check_ifunc_resolver,
+                                         &is_ifunc_resolver, true);
+      if (is_ifunc_resolver || is_caller_ifunc_resolver (cnode))
+       cnode->called_by_ifunc_resolver = true;
+    }
+
+  bitmap_clear (ifunc_ref_map);
+}
+
 /* Verify symbol table for internal consistency.  */
 
 DEBUG_FUNCTION void

diff --git a/gcc/testsuite/gcc.dg/pr114115.c b/gcc/testsuite/gcc.dg/pr114115.c
new file mode 100644 (file)
index 0000000..2629f59
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr114115.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-O0 -fprofile-generate -fdump-tree-optimized" } */
+/* { dg-require-profiling "-fprofile-generate" } */
+/* { dg-require-ifunc "" } */
+
+void *foo_ifunc2() __attribute__((ifunc("foo_resolver")));
+
+void bar(void)
+{
+}
+
+static int f3()
+{
+  bar ();
+  return 5;
+}
+
+void (*foo_resolver(void))(void)
+{
+  f3();
+  return bar;
+}
+
+/* { dg-final { scan-tree-dump-not "__gcov_indirect_call_profiler_v" "optimized" } } */

diff --git a/gcc/tree-profile.c b/gcc/tree-profile.c
index 5a74cc96e1323f4684e09b4c8b34076088cd0d30..64d25cf4d1781212a60bd118d7410ba6431bcb15 100644 (file)
--- a/gcc/tree-profile.c
+++ b/gcc/tree-profile.c
@@ -418,7 +418,13 @@ gimple_gen_ic_func_profiler (void)
   gcall *stmt1;
   tree tree_uid, cur_func, void0;
 
-  if (c_node->only_called_directly_p ())
+  /* Disable indirect call profiling for an IFUNC resolver and its
+     callees since it requires TLS which hasn't been set up yet when
+     the dynamic linker is resolving IFUNC symbols.  See
+     https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114115
+   */
+  if (c_node->only_called_directly_p ()
+      || c_node->called_by_ifunc_resolver)
     return;
 
   gimple_init_gcov_profiler ();