From 620bf162a048fdf29fdfcedc12abae79cffeedf4 Mon Sep 17 00:00:00 2001
From: gingerBill <gingerBill@users.noreply.github.com>
Date: Sat, 2 Aug 2025 12:32:18 +0100
Subject: Cache const `string16` in LLVM

---
 src/llvm_backend_general.cpp | 71 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 70 insertions(+), 1 deletion(-)

(limited to 'src/llvm_backend_general.cpp')

diff --git a/src/llvm_backend_general.cpp b/src/llvm_backend_general.cpp
index 9ef1c23c0..064d0ef39 100644
--- a/src/llvm_backend_general.cpp
+++ b/src/llvm_backend_general.cpp
@@ -85,6 +85,7 @@ gb_internal void lb_init_module(lbModule *m, Checker *c) {
 	string_map_init(&m->members);
 	string_map_init(&m->procedures);
 	string_map_init(&m->const_strings);
+	string16_map_init(&m->const_string16s);
 	map_init(&m->function_type_map);
 	string_map_init(&m->gen_procs);
 	if (USE_SEPARATE_MODULES) {
@@ -2716,7 +2717,18 @@ gb_internal LLVMValueRef lb_find_or_add_entity_string_ptr(lbModule *m, String co
 }
 
 gb_internal LLVMValueRef lb_find_or_add_entity_string16_ptr(lbModule *m, String16 const &str, bool custom_link_section) {
-	// TODO(bill): caching for UTF-16 strings
+	String16HashKey key = {};
+	LLVMValueRef *found = nullptr;
+
+	if (!custom_link_section) {
+		key = string_hash_string(str);
+		found = string16_map_get(&m->const_string16s, key);
+	}
+	if (found != nullptr) {
+		return *found;
+	}
+
+
 
 	LLVMValueRef indices[2] = {llvm_zero(m), llvm_zero(m)};
 
@@ -2749,6 +2761,9 @@ gb_internal LLVMValueRef lb_find_or_add_entity_string16_ptr(lbModule *m, String1
 	LLVMSetAlignment(global_data, 1);
 
 	LLVMValueRef ptr = LLVMConstInBoundsGEP2(type, global_data, indices, 2);
+	if (!custom_link_section) {
+		string16_map_set(&m->const_string16s, key, ptr);
+	}
 	return ptr;
 }
 
@@ -2812,6 +2827,60 @@ gb_internal lbValue lb_find_or_add_entity_string_byte_slice_with_type(lbModule *
 	return res;
 }
 
+gb_internal lbValue lb_find_or_add_entity_string16_slice_with_type(lbModule *m, String16 const &str, Type *slice_type) {
+	GB_ASSERT(is_type_slice(slice_type));
+	LLVMValueRef indices[2] = {llvm_zero(m), llvm_zero(m)};
+	LLVMValueRef data = nullptr;
+	{
+		LLVMTypeRef llvm_u16 = LLVMInt16TypeInContext(m->ctx);
+
+		TEMPORARY_ALLOCATOR_GUARD();
+
+		LLVMValueRef *values = gb_alloc_array(temporary_allocator(), LLVMValueRef, str.len+1);
+
+		for (isize i = 0; i < str.len; i++) {
+			values[i] = LLVMConstInt(llvm_u16, str.text[i], false);
+		}
+		values[str.len] = LLVMConstInt(llvm_u16, 0, false);
+
+		data = LLVMConstArray(llvm_u16, values, cast(unsigned)(str.len+1));
+	}
+
+	u32 id = m->global_array_index.fetch_add(1);
+	gbString name = gb_string_make(temporary_allocator(), "csba$");
+	name = gb_string_appendc(name, m->module_name);
+	name = gb_string_append_fmt(name, "$%x", id);
+
+	LLVMTypeRef type = LLVMTypeOf(data);
+	LLVMValueRef global_data = LLVMAddGlobal(m->mod, type, name);
+	LLVMSetInitializer(global_data, data);
+	lb_make_global_private_const(global_data);
+	LLVMSetAlignment(global_data, 1);
+
+	i64 data_len = str.len;
+	LLVMValueRef ptr = nullptr;
+	if (data_len != 0) {
+		ptr = LLVMConstInBoundsGEP2(type, global_data, indices, 2);
+	} else {
+		ptr = LLVMConstNull(lb_type(m, t_u8_ptr));
+	}
+	if (!is_type_u16_slice(slice_type)) {
+		Type *bt = base_type(slice_type);
+		Type *elem = bt->Slice.elem;
+		i64 sz = type_size_of(elem);
+		GB_ASSERT(sz > 0);
+		ptr = LLVMConstPointerCast(ptr, lb_type(m, alloc_type_pointer(elem)));
+		data_len /= sz;
+	}
+
+	LLVMValueRef len = LLVMConstInt(lb_type(m, t_int), data_len, true);
+	LLVMValueRef values[2] = {ptr, len};
+
+	lbValue res = {};
+	res.value = llvm_const_named_struct(m, slice_type, values, 2);
+	res.type = slice_type;
+	return res;
+}
 
 
 gb_internal lbValue lb_find_ident(lbProcedure *p, lbModule *m, Entity *e, Ast *expr) {
-- 
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