[PATCH] AArch64: Fix PR103085

Wilco Dijkstra Wilco.Dijkstra@arm.com
Fri Nov 5 13:55:10 GMT 2021


The stack protector implementation hides symbols in a const unspec, which means
movdi/movsi patterns must always support const on symbol operands and explicitly
strip away the unspec. Do this for the recently added GOT alternatives. Add a
test to ensure stack-protector tests GOT accesses as well.

Passes bootstrap and regress. OK for commit?

2021-11-05  Wilco Dijkstra  <wdijkstr@arm.com>

        PR target/103085
        * config/aarch64/aarch64.c (aarch64_mov_operand_p): Strip the salt first.
        * config/aarch64/constraints.md: Support const in Usw.

        * gcc.target/aarch64/pr103085.c: New test
---

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 430ea036a7be4da842fd08998923a3462457dbfd..39de231d8ac6d10362cdd2b48eb9bd9de60c6703 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -20155,12 +20155,14 @@ aarch64_mov_operand_p (rtx x, machine_mode mode)
       return aarch64_simd_valid_immediate (x, NULL);
     }
 
+  /* Remove UNSPEC_SALT_ADDR before checking symbol reference.  */
+  x = strip_salt (x);
+
   /* GOT accesses are valid moves.  */
   if (SYMBOL_REF_P (x)
       && aarch64_classify_symbolic_expression (x) == SYMBOL_SMALL_GOT_4G)
     return true;
 
-  x = strip_salt (x);
   if (SYMBOL_REF_P (x) && mode == DImode && CONSTANT_ADDRESS_P (x))
     return true;
 
diff --git a/gcc/config/aarch64/constraints.md b/gcc/config/aarch64/constraints.md
index 70ca66070217d06f974b18f7690326bc329fed89..da5438e7ce254272eb10e9ac60d5367c46635e84 100644
--- a/gcc/config/aarch64/constraints.md
+++ b/gcc/config/aarch64/constraints.md
@@ -152,10 +152,11 @@ (define_constraint "Usa"
        (match_test "aarch64_symbolic_address_p (op)")
        (match_test "aarch64_mov_operand_p (op, GET_MODE (op))")))
 
+;; const is needed here to support UNSPEC_SALT_ADDR.
 (define_constraint "Usw"
   "@internal
    A constraint that matches a small GOT access."
-  (and (match_code "symbol_ref")
+  (and (match_code "const,symbol_ref")
        (match_test "aarch64_classify_symbolic_expression (op)
 		     == SYMBOL_SMALL_GOT_4G")))
 
diff --git a/gcc/testsuite/gcc.target/aarch64/pr103085.c b/gcc/testsuite/gcc.target/aarch64/pr103085.c
new file mode 100644
index 0000000000000000000000000000000000000000..dbc9c15b71f224b3c7dec0cca5655a31adc207f6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/pr103085.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fstack-protector-strong -fPIC" } */
+
+void g(int*);
+void
+f (int x)
+{
+  int arr[10];
+  g (arr);
+}
+


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