From b006b9833466933660e1c052454239e4ca3e3f4d Mon Sep 17 00:00:00 2001
From: Ziyao <ziyao@disroot.org>
Date: Sun, 9 Apr 2023 06:06:10 +0800
Subject: [PATCH] Fix passing of large function arguments on riscv64

- Correct stack adjustment in gfunc_call()
- Add a regression test (130_large_argument)
---
 riscv64-gen.c                          | 19 ++++++++----
 tests/tests2/130_large_argument.c      | 41 ++++++++++++++++++++++++++
 tests/tests2/130_large_argument.expect |  3 ++
 3 files changed, 57 insertions(+), 6 deletions(-)
 create mode 100644 tests/tests2/130_large_argument.c
 create mode 100644 tests/tests2/130_large_argument.expect

diff --git a/riscv64-gen.c b/riscv64-gen.c
index 490eca79..8a17b701 100644
--- a/riscv64-gen.c
+++ b/riscv64-gen.c
@@ -627,10 +627,14 @@ ST_FUNC void gfunc_call(int nb_args)
     if ((vtop->r & VT_VALMASK) == VT_CMP)
       gv(RC_INT);
 
+
     if (stack_add) {
-        if (stack_add >= 0x1000) {
-            o(0x37 | (5 << 7) | (-stack_add & 0xfffff000)); //lui t0, upper(v)
-            EI(0x13, 0, 5, 5, -stack_add << 20 >> 20); // addi t0, t0, lo(v)
+        if (stack_add >= 0x800) {
+            unsigned int bit11 = (((unsigned int)-stack_add) >> 11) & 1;
+            o(0x37 | (5 << 7) |
+              ((-stack_add + (bit11 << 12)) & 0xfffff000)); //lui t0, upper(v)
+            EI(0x13, 0, 5, 5, ((-stack_add & 0xfff) - bit11 * (1 << 12)));
+                                                         // addi t0, t0, lo(v)
             ER(0x33, 0, 2, 2, 5, 0); // add sp, sp, t0
         }
         else
@@ -757,9 +761,12 @@ done:
     gcall_or_jmp(1);
     vtop -= nb_args + 1;
     if (stack_add) {
-        if (stack_add >= 0x1000) {
-            o(0x37 | (5 << 7) | (stack_add & 0xfffff000)); //lui t0, upper(v)
-            EI(0x13, 0, 5, 5, stack_add << 20 >> 20); // addi t0, t0, lo(v)
+        if (stack_add >= 0x800) {
+            unsigned int bit11 = ((unsigned int)stack_add >> 11) & 1;
+            o(0x37 | (5 << 7) |
+              ((stack_add + (bit11 << 12)) & 0xfffff000)); //lui t0, upper(v)
+            EI(0x13, 0, 5, 5, (stack_add & 0xfff) - bit11 * (1 << 12));
+                                                           // addi t0, t0, lo(v)
             ER(0x33, 0, 2, 2, 5, 0); // add sp, sp, t0
         }
         else
diff --git a/tests/tests2/130_large_argument.c b/tests/tests2/130_large_argument.c
new file mode 100644
index 00000000..8415c85e
--- /dev/null
+++ b/tests/tests2/130_large_argument.c
@@ -0,0 +1,41 @@
+#include<stdio.h>
+
+struct large1 {
+    int a[768];
+};
+
+struct large2 {
+    int a[1920];
+};
+
+void pass_large_struct1(struct large1 in)
+{
+    printf("%d %d\n", in.a[200], in.a[767]);
+    return;
+}
+
+void pass_large_struct2(struct large2 in)
+{
+    printf("%d %d %d\n", in.a[200], in.a[1023], in.a[1919]);
+    return;
+}
+
+void pass_many_args(int a, int b, int c, int d, int e, int f, int g, int h, int i,
+                    int j, int k, int l, int m)
+{
+    printf("%d %d %d %d %d %d %d %d %d %d %d %d %d\n", a, b, c, d, e, f, g, h, i,
+           j, k, l, m);
+    return;
+}
+
+struct large1 l1 = { .a = { [200] = 1, [767] = 2 } };
+struct large2 l2 = { .a = { [200] = 3, [1023] = 4, [1919] = 5} };
+
+int main(void)
+{
+    pass_large_struct1(l1);
+    pass_large_struct2(l2);
+    pass_many_args(13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1);
+
+    return 0;
+}
diff --git a/tests/tests2/130_large_argument.expect b/tests/tests2/130_large_argument.expect
new file mode 100644
index 00000000..8c5d9cd7
--- /dev/null
+++ b/tests/tests2/130_large_argument.expect
@@ -0,0 +1,3 @@
+1 2
+3 4 5
+13 12 11 10 9 8 7 6 5 4 3 2 1