From eb77e3381fac5f5bba2254cf5a7369aaea930e4e Mon Sep 17 00:00:00 2001
From: Luuk de Gram <luuk@degram.dev>
Date: Thu, 27 Apr 2023 16:15:14 +0200
Subject: wasm: implement `@frameAddress`

---
 src/arch/wasm/CodeGen.zig | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/arch/wasm/CodeGen.zig b/src/arch/wasm/CodeGen.zig
index 11969d567a..3ae7f639fe 100644
--- a/src/arch/wasm/CodeGen.zig
+++ b/src/arch/wasm/CodeGen.zig
@@ -1242,7 +1242,7 @@ fn genFunc(func: *CodeGen) InnerError!void {
 
     // check if we have to initialize and allocate anything into the stack frame.
     // If so, create enough stack space and insert the instructions at the front of the list.
-    if (func.stack_size > 0) {
+    if (func.initial_stack_value != .none) {
         var prologue = std.ArrayList(Mir.Inst).init(func.gpa);
         defer prologue.deinit();
 
@@ -1963,11 +1963,11 @@ fn genInst(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
         .tag_name => func.airTagName(inst),
 
         .error_set_has_value => func.airErrorSetHasValue(inst),
+        .frame_addr => func.airFrameAddress(inst),
 
         .mul_sat,
         .mod,
         .assembly,
-        .frame_addr,
         .bit_reverse,
         .is_err_ptr,
         .is_non_err_ptr,
@@ -6969,3 +6969,12 @@ fn airAtomicStore(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
 
     return func.finishAir(inst, .none, &.{ bin_op.lhs, bin_op.rhs });
 }
+
+fn airFrameAddress(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
+    if (func.initial_stack_value == .none) {
+        try func.initializeStack();
+    }
+    try func.emitWValue(func.bottom_stack_value);
+    const result = try WValue.toLocal(.stack, func, Type.usize);
+    return func.finishAir(inst, result, &.{});
+}
-- 
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