x86-64: Fix call saved register restore

Loads of VT_LLOCAL values (which effectively represent saved
addresses of lvalues) were done in VT_INT type, loosing the upper
32 bits.  Needs to be done in VT_PTR type.

2 files changed, 22 insertions, 2 deletions

diff --git a/tests/tcctest.c b/tests/tcctest.c
index 9f88c51..1b04c1f 100644
--- a/tests/tcctest.c
+++ b/tests/tcctest.c
@@ -88,6 +88,7 @@ void weak_test(void);
 void global_data_test(void);
 void cmp_comparison_test(void);
 void math_cmp_test(void);
+void callsave_test(void);
 
 int fib(int n);
 void num(int n);
@@ -596,6 +597,7 @@ int main(int argc, char **argv)
     global_data_test();
     cmp_comparison_test();
     math_cmp_test();
+    callsave_test();
     return 0; 
 }
 
@@ -2658,3 +2660,21 @@ void math_cmp_test(void)
   FCMP(nan, nan, >, !=, 4);
   FCMP(nan, nan, <=, !=, 5);
 }
+
+double get100 () { return 100.0; }
+
+void callsave_test(void)
+{
+  int i, s; double *d; double t;
+  s = sizeof (double);
+  printf ("callsavetest: %d\n", s);
+  d = alloca (sizeof(double));
+  d[0] = 10.0;
+  /* x86-64 had a bug were the next call to get100 would evict
+     the lvalue &d[0] as VT_LLOCAL, and the reload would be done
+     in int type, not pointer type.  When alloca returns a pointer
+     with the high 32 bit set (which is likely on x86-64) the access
+     generates a segfault.  */
+  i = d[0] > get100 ();
+  printf ("%d\n", i);
+}
diff --git a/x86_64-gen.c b/x86_64-gen.c
index 6dfe1e4..1fa8dd5 100644
--- a/x86_64-gen.c
+++ b/x86_64-gen.c
@@ -1460,7 +1460,7 @@ void gen_opf(int op)
             if ((r & VT_VALMASK) == VT_LLOCAL) {
                 SValue v1;
                 r = get_reg(RC_INT);
-                v1.type.t = VT_INT;
+                v1.type.t = VT_PTR;
                 v1.r = VT_LOCAL | VT_LVAL;
                 v1.c.ul = fc;
                 load(r, &v1);
@@ -1531,7 +1531,7 @@ void gen_opf(int op)
                 if ((r & VT_VALMASK) == VT_LLOCAL) {
                     SValue v1;
                     r = get_reg(RC_INT);
-                    v1.type.t = VT_INT;
+                    v1.type.t = VT_PTR;
                     v1.r = VT_LOCAL | VT_LVAL;
                     v1.c.ul = fc;
                     load(r, &v1);