funcall generates args test case

test_framework/regalloc.py

@@ -302,7 +302,6 @@ class CoalesceTest(NamedTuple):
     "fourteen_pseudos_interfere.c": NoSpillTest(),
     "track_dbl_arg_registers.c": NoSpillTest(),
     "store_pointer_in_register.c": NoSpillTest(),
-    "funcall_generates_args.c": NoSpillTest(),
     "force_spill.c": SpillTest(
         max_spilled_instructions=3,
         max_spilled_pseudos=1,

test_properties.json

@@ -431,8 +431,9 @@
         "chapter_20/int_only/no_coalescing/division_uses_ax.c": [
             "chapter_20/libraries/util.c"
         ],
-        "chapter_20/int_only/with_coalescing/funcall_generates_args.c": [
-            "chapter_20/libraries/funcall_generates_args_lib.c"
+        "chapter_20/int_only/no_coalescing/funcall_generates_args.c": [
+            "chapter_20/libraries/funcall_generates_args_lib.c",
+            "chapter_20/libraries/util.c"
         ],
         "chapter_20/int_only/no_coalescing/force_spill.c": [
             "chapter_20/libraries/util.c"

tests/chapter_20/int_only/no_coalescing/funcall_generates_args.c

@@ -0,0 +1,39 @@
+/* Make sure we recognize that a function uses some parameter-passing registers,
+ * determined by its declaration. Don't inspect assembly, just validate behavior.
+ * NOTE: only works as intended after we've implemented register coalescing.
+ * */
+
+#include "util.h"
+
+// defined in funcall_generates_args_lib,
+// exits early with return code -1 if a and b don't have
+// the correc values
+int f(int a, int b);
+
+int glob = 10;
+int x = 0;
+int y = 0;
+int target(void) {
+    int a = glob + 1;
+    int b = glob + 2;
+    // We'll coalesce a and b with EDI/ESI because they're copied into those
+    // registers. If we don't recognize that EDI/ESI are live when we call f,
+    // we'll coalesce the temporaries that hold a * glob and b * glob
+    // with EDI/ESI too, since we'll generate the following assembly:
+    // movl  %a, %tmp
+    // imull %glob, %tmp
+    // movl  %tmp, %x
+    // and similar for y/b
+    x = a * glob;
+    y = b * glob;
+    // validate a and b
+    f(a, b);
+    // validate x and y
+    check_one_int(x, 110);
+    check_one_int(y, 120);
+    return 0;
+}
+
+int main(void) {
+    return target();
+}

tests/chapter_20/libraries/funcall_generates_args_lib.c

@@ -1,3 +1,19 @@
+// helper function for funcall_generates_args
+
+#include <stdio.h>
+#include <stdlib.h>
+
+// a and b should be 11 and 12
 int f(int a, int b) {
-    return a == 11 && b == 12;
+    if (a != 11) {
+        printf("Expected a to be 11 but found %d\n", a);
+        exit(-1);
+    }
+
+    if (b != 12) {
+        printf("Expected b to be 12 but found %d\n", b);
+        exit(-1);
+    }
+
+    return 0;
 }