[gcc(refs/users/marxin/heads/marxin-gcc-benchmark-branch)] cgraph: Avoid creating multiple *.localalias aliases with the same name [PR93384]

[Martin Liska]

https://gcc.gnu.org/g:5fb07870fa4c86f529930bae76689ed5bdfcb192

commit 5fb07870fa4c86f529930bae76689ed5bdfcb192
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Jan 30 21:32:36 2020 +0100

    cgraph: Avoid creating multiple *.localalias aliases with the same name [PR93384]
    
    The following testcase FAILs on powerpc64le-linux with assembler errors, as we
    emit a call to bar.localalias, then .set bar.localalias, bar twice and then
    another call to bar.localalias.  The problem is that bar.localalias can be created
    at various stages and e.g. ipa-pure-const can slightly adjust the original decl,
    so that the existing bar.localalias isn't considered usable (different
    flags_from_decl_or_type).  In that case, we'd create another bar.localalias, which
    clashes with the existing name.
    
    Fixed by retrying with another name if it is already present.  The various localalias
    aliases shouldn't be that many, from different partitions they would be lto_priv
    suffixed and in most cases they would already have the same type/flags/attributes.
    
    2020-01-30  Jakub Jelinek  <jakub@redhat.com>
    
            PR lto/93384
            * symtab.c (symtab_node::noninterposable_alias): If localalias
            already exists, but is not usable, append numbers after it until
            a unique name is found.  Formatting fix.
    
            * gcc.dg/lto/pr93384_0.c: New test.
            * gcc.dg/lto/pr93384_1.c: New file.

Diff:
---
 gcc/ChangeLog                        |  5 +++++
 gcc/symtab.c                         | 14 ++++++++++++--
 gcc/testsuite/ChangeLog              |  4 ++++
 gcc/testsuite/gcc.dg/lto/pr93384_0.c | 12 ++++++++++++
 gcc/testsuite/gcc.dg/lto/pr93384_1.c |  2 ++
 5 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f2cc0276600..a45d0907e9d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,10 @@
 2020-01-30  Jakub Jelinek  <jakub@redhat.com>
 
+	PR lto/93384
+	* symtab.c (symtab_node::noninterposable_alias): If localalias
+	already exists, but is not usable, append numbers after it until
+	a unique name is found.  Formatting fix.
+
 	PR middle-end/93505
 	* combine.c (simplify_comparison) <case ROTATE>: Punt on out of range
 	rotate counts.
diff --git a/gcc/symtab.c b/gcc/symtab.c
index f141200a452..eae891ab211 100644
--- a/gcc/symtab.c
+++ b/gcc/symtab.c
@@ -1864,7 +1864,7 @@ symtab_node::noninterposable_alias (void)
   symtab_node *node = ultimate_alias_target ();
   gcc_assert (!node->alias && !node->weakref);
   node->call_for_symbol_and_aliases (symtab_node::noninterposable_alias,
-				   (void *)&new_node, true);
+				     (void *)&new_node, true);
   if (new_node)
     return new_node;
 
@@ -1875,7 +1875,17 @@ symtab_node::noninterposable_alias (void)
   /* Otherwise create a new one.  */
   new_decl = copy_node (node->decl);
   DECL_DLLIMPORT_P (new_decl) = 0;
-  DECL_NAME (new_decl) = clone_function_name (node->decl, "localalias");
+  tree name = clone_function_name (node->decl, "localalias");
+  if (!flag_wpa)
+    {
+      unsigned long num = 0;
+      /* In the rare case we already have a localalias, but the above
+	 node->call_for_symbol_and_aliases call didn't find any suitable,
+	 iterate until we find one not used yet.  */
+      while (symtab_node::get_for_asmname (name))
+	name = clone_function_name (node->decl, "localalias", num++);
+    }
+  DECL_NAME (new_decl) = name;
   if (TREE_CODE (new_decl) == FUNCTION_DECL)
     DECL_STRUCT_FUNCTION (new_decl) = NULL;
   DECL_INITIAL (new_decl) = NULL;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ce53e2c8bf8..4503016a73e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,9 @@
 2020-01-30  Jakub Jelinek  <jakub@redhat.com>
 
+	PR lto/93384
+	* gcc.dg/lto/pr93384_0.c: New test.
+	* gcc.dg/lto/pr93384_1.c: New file.
+
 	PR middle-end/93505
 	* gcc.c-torture/compile/pr93505.c: New test.
 
diff --git a/gcc/testsuite/gcc.dg/lto/pr93384_0.c b/gcc/testsuite/gcc.dg/lto/pr93384_0.c
new file mode 100644
index 00000000000..fdcb9a23fc6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr93384_0.c
@@ -0,0 +1,12 @@
+/* PR lto/93384 */
+/* { dg-lto-do link } */
+/* { dg-require-effective-target fpic } */
+/* { dg-require-effective-target shared } */
+/* { dg-lto-options { { -O2 -flto -ffat-lto-objects -fpic -fno-semantic-interposition } } } */
+/* { dg-extra-ld-options { -shared -flto-partition=none } } */
+
+void bar (void);
+__attribute__((noipa)) void quux (int x) { if (x == 5) bar (); }
+__attribute__((noipa, noreturn)) void foo (void) { while (1) ; }
+__attribute__((noinline)) void bar (void) { asm (""); quux (7); foo (); }
+void baz (int x) { if (x) bar (); }
diff --git a/gcc/testsuite/gcc.dg/lto/pr93384_1.c b/gcc/testsuite/gcc.dg/lto/pr93384_1.c
new file mode 100644
index 00000000000..1b9d6af310f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr93384_1.c
@@ -0,0 +1,2 @@
+extern void bar (void);
+void qux (int x) { if (!x) bar (); }