From: Richard Biener <rguenther@suse.de>
Date: Fri, 28 Feb 2025 13:09:29 +0000 (+0100)
Subject: lto/91299 - weak definition inlined with LTO
X-Git-Tag: basepoints/gcc-16~1799
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bc34db5b12e008f6ec4fdf4ebd22263c8617e5e3;p=thirdparty%2Fgcc.git

lto/91299 - weak definition inlined with LTO

The following fixes a thinko in the handling of interposed weak
definitions which confused the interposition check in
get_availability by setting DECL_EXTERNAL too early.

	PR lto/91299
gcc/lto/
	* lto-symtab.cc (lto_symtab_merge_symbols): Set DECL_EXTERNAL
	only after calling get_availability.

gcc/testsuite/
	* gcc.dg/lto/pr91299_0.c: New testcase.
	* gcc.dg/lto/pr91299_1.c: Likewise.
---

diff --git a/gcc/lto/lto-symtab.cc b/gcc/lto/lto-symtab.cc
index bc3c144e444..66674a4415f 100644
--- a/gcc/lto/lto-symtab.cc
+++ b/gcc/lto/lto-symtab.cc
@@ -1016,7 +1016,6 @@ lto_symtab_merge_symbols (void)
 		  || node->resolution == LDPR_RESOLVED_EXEC
 		  || node->resolution == LDPR_RESOLVED_DYN))
 	    {
-	      DECL_EXTERNAL (node->decl) = 1;
 	      /* If alias to local symbol was preempted by external definition,
 		 we know it is not pointing to the local symbol.  Remove it.  */
 	      if (node->alias
@@ -1042,6 +1041,7 @@ lto_symtab_merge_symbols (void)
 		      node->remove_all_references ();
 		    }
 		}
+	      DECL_EXTERNAL (node->decl) = 1;
 	    }
 
 	  if (!(cnode = dyn_cast <cgraph_node *> (node))
diff --git a/gcc/testsuite/gcc.dg/lto/pr91299_0.c b/gcc/testsuite/gcc.dg/lto/pr91299_0.c
new file mode 100644
index 00000000000..d9a8b21d6b8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr91299_0.c
@@ -0,0 +1,16 @@
+/* { dg-lto-do run } */
+/* { dg-lto-options { { -O2 -flto } } } */
+
+__attribute__((weak)) int get_t(void)
+{
+  return 0;
+}
+
+int a;
+int main(void)
+{
+  a = get_t();
+  if (a != 1)
+    __builtin_abort ();
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/lto/pr91299_1.c b/gcc/testsuite/gcc.dg/lto/pr91299_1.c
new file mode 100644
index 00000000000..29a28520f7b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr91299_1.c
@@ -0,0 +1,6 @@
+/* { dg-options "-fno-lto" } */
+
+int get_t(void)
+{
+    return 1;
+}