From 1abedb6175e11a7353f98003c7c42ffed65e062c Mon Sep 17 00:00:00 2001
From: David Mak <chmakac@connect.ust.hk>
Date: Mon, 25 Nov 2024 15:26:28 +0800
Subject: [PATCH] [core] codegen: Add call_memcpy_generic_array

Replacement for Instance<Ptr>::copy_from from legacy ndstrides
implementation.
---
 nac3core/src/codegen/llvm_intrinsics.rs | 42 +++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/nac3core/src/codegen/llvm_intrinsics.rs b/nac3core/src/codegen/llvm_intrinsics.rs
index 9c11f88d..287d1c7e 100644
--- a/nac3core/src/codegen/llvm_intrinsics.rs
+++ b/nac3core/src/codegen/llvm_intrinsics.rs
@@ -201,6 +201,48 @@ pub fn call_memcpy_generic<'ctx>(
     call_memcpy(ctx, dest, src, len, is_volatile);
 }
 
+/// Invokes the `llvm.memcpy` intrinsic.
+///
+/// Unlike [`call_memcpy`], this function accepts any type of pointer value. If `dest` or `src` is
+/// not a pointer to an integer, the pointer(s) will be cast to `i8*` before invoking `memcpy`.
+/// Moreover, `len` now refers to the number of elements (rather than bytes) to copy.
+pub fn call_memcpy_generic_array<'ctx>(
+    ctx: &CodeGenContext<'ctx, '_>,
+    dest: PointerValue<'ctx>,
+    src: PointerValue<'ctx>,
+    len: IntValue<'ctx>,
+    is_volatile: IntValue<'ctx>,
+) {
+    let llvm_i8 = ctx.ctx.i8_type();
+    let llvm_p0i8 = llvm_i8.ptr_type(AddressSpace::default());
+    let llvm_sizeof_expr_t = llvm_i8.size_of().get_type();
+
+    let dest_elem_t = dest.get_type().get_element_type();
+    let src_elem_t = src.get_type().get_element_type();
+
+    let dest = if matches!(dest_elem_t, IntType(t) if t.get_bit_width() == 8) {
+        dest
+    } else {
+        ctx.builder
+            .build_bit_cast(dest, llvm_p0i8, "")
+            .map(BasicValueEnum::into_pointer_value)
+            .unwrap()
+    };
+    let src = if matches!(src_elem_t, IntType(t) if t.get_bit_width() == 8) {
+        src
+    } else {
+        ctx.builder
+            .build_bit_cast(src, llvm_p0i8, "")
+            .map(BasicValueEnum::into_pointer_value)
+            .unwrap()
+    };
+
+    let len = ctx.builder.build_int_cast(len, llvm_sizeof_expr_t, "").unwrap();
+    let len = ctx.builder.build_int_mul(len, src_elem_t.size_of().unwrap(), "").unwrap();
+
+    call_memcpy(ctx, dest, src, len, is_volatile);
+}
+
 /// Macro to find and generate build call for llvm intrinsic (body of llvm intrinsic function)
 ///
 /// Arguments: