public inbox for gcc-patches@gcc.gnu.org
 help / color / mirror / Atom feed
* [PATCH v2] tree-profile: Don't instrument an IFUNC resolver nor its callees
@ 2024-03-05 21:45 H.J. Lu
  2024-04-02 14:41 ` PING: " H.J. Lu
  0 siblings, 1 reply; 6+ messages in thread
From: H.J. Lu @ 2024-03-05 21:45 UTC (permalink / raw)
  To: gcc-patches; +Cc: hubicka

We can't instrument an IFUNC resolver nor its callees as it may require
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.  Update tree_profiling to skip
functions called by IFUNC resolver.

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.cc (symbol_table::compile): Call
	symtab_node::check_ifunc_callee_symtab_nodes.
	* symtab.cc (check_ifunc_resolver): New.
	(ifunc_ref_map): Likewise.
	(is_caller_ifunc_resolver): Likewise.
	(symtab_node::check_ifunc_callee_symtab_nodes): Likewise.
	* tree-profile.cc (tree_profiling): Do not instrument an IFUNC
	resolver nor its callees.

gcc/testsuite/ChangeLog:

	PR tree-optimization/114115
	* gcc.dg/pr114115.c: New test.
---
 gcc/cgraph.h                    |  6 +++
 gcc/cgraphunit.cc               |  2 +
 gcc/symtab.cc                   | 89 +++++++++++++++++++++++++++++++++
 gcc/testsuite/gcc.dg/pr114115.c | 24 +++++++++
 gcc/tree-profile.cc             |  4 ++
 5 files changed, 125 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/pr114115.c

diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index 47f35e8078d..a8c3224802c 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -479,6 +479,9 @@ 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);
 
@@ -896,6 +899,7 @@ struct GTY((tag ("SYMTAB_FUNCTION"))) cgraph_node : public symtab_node
       redefined_extern_inline (false), tm_may_enter_irr (false),
       ipcp_clone (false), declare_variant_alt (false),
       calls_declare_variant_alt (false), gc_candidate (false),
+      called_by_ifunc_resolver (false),
       m_uid (uid), m_summary_id (-1)
   {}
 
@@ -1495,6 +1499,8 @@ struct GTY((tag ("SYMTAB_FUNCTION"))) cgraph_node : public symtab_node
      is set for local SIMD clones when they are created and cleared if the
      vectorizer uses them.  */
   unsigned gc_candidate : 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.cc b/gcc/cgraphunit.cc
index d200166f7e9..2bd0289ffba 100644
--- a/gcc/cgraphunit.cc
+++ b/gcc/cgraphunit.cc
@@ -2317,6 +2317,8 @@ 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.cc b/gcc/symtab.cc
index 4c7e3c135ca..3256133891d 100644
--- a/gcc/symtab.cc
+++ b/gcc/symtab.cc
@@ -1369,6 +1369,95 @@ 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
index 00000000000..2629f591877
--- /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.cc b/gcc/tree-profile.cc
index aed13e2b1bc..2e55a5d8402 100644
--- a/gcc/tree-profile.cc
+++ b/gcc/tree-profile.cc
@@ -848,6 +848,10 @@ tree_profiling (void)
 	    }
 	}
 
+      /* Do not instrument an IFUNC resolver nor its callees.  */
+      if (node->called_by_ifunc_resolver)
+	continue;
+
       push_cfun (DECL_STRUCT_FUNCTION (node->decl));
 
       if (dump_file)
-- 
2.44.0


^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2024-04-03 12:42 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-03-05 21:45 [PATCH v2] tree-profile: Don't instrument an IFUNC resolver nor its callees H.J. Lu
2024-04-02 14:41 ` PING: " H.J. Lu
2024-04-02 14:50   ` Jan Hubicka
2024-04-02 15:57     ` H.J. Lu
2024-04-02 17:03       ` Jan Hubicka
2024-04-03 12:41         ` H.J. Lu

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).