[PATCH olang v2 4/4] codegen: operate mov instructions based on the symbol's type

[Carlos Maniero <carlos@maniero.me>]

Signed-off-by: Carlos Maniero <carlos@maniero.me>
---
 src/codegen_linux_x86_64.c                    | 60 ++++++++++++++++---
 src/type.c                                    | 18 ++++++
 src/type.h                                    |  5 +-
 .../tests/0026_primitive_unsigneds.ol         | 27 +++++++++
 4 files changed, 100 insertions(+), 10 deletions(-)
 create mode 100644 tests/integration/tests/0026_primitive_unsigneds.ol

diff --git a/src/codegen_linux_x86_64.c b/src/codegen_linux_x86_64.c
index 1fa6c58..25cda2d 100644
--- a/src/codegen_linux_x86_64.c
+++ b/src/codegen_linux_x86_64.c
@@ -26,6 +26,10 @@
 #define SYS_exit (60)
 #define PTR_HEX_CSTR_SIZE (18 + 1)
 
+// The call instruction pushes EIP into stack so the first 8 bytes from stack
+// must be preserved else the ret instruction will jump to nowere.
+#define X86_CALL_EIP_STACK_OFFSET (8)
+
 // FIXME: move label_index to codegen_linux_x86_64_t structure
 size_t label_index;
 
@@ -35,6 +39,12 @@ codegen_linux_x86_64_emit_start_entrypoint(codegen_x86_64_t *codegen);
 static void
 codegen_linux_x86_64_emit_function(codegen_x86_64_t *codegen, ast_fn_definition_t *fn);
 
+static size_t
+type_to_bytes(type_t *type);
+
+static char *
+get_accumulator_reg_for(size_t bytes);
+
 void
 codegen_linux_x86_64_init(codegen_x86_64_t *codegen, arena_t *arena, FILE *out)
 {
@@ -105,7 +115,10 @@ codegen_linux_x86_64_emit_expression(codegen_x86_64_t *codegen, ast_node_t *expr
             size_t *offset = (size_t *)map_get(codegen->symbols_stack_offset, symbol_ptr);
             assert(offset);
 
-            fprintf(codegen->out, "    mov -%ld(%%rbp), %%rax\n", *offset);
+            fprintf(codegen->out,
+                    "    mov -%ld(%%rbp), %s\n",
+                    *offset,
+                    get_accumulator_reg_for(type_to_bytes(&symbol->type)));
             return;
         }
         case AST_NODE_BINARY_OP: {
@@ -366,12 +379,18 @@ codegen_linux_x86_64_emit_block(codegen_x86_64_t *codegen, ast_block_t *block)
                     codegen_linux_x86_64_emit_expression(codegen, var_def.value);
                 }
 
-                codegen->base_offset += 8;
                 size_t *offset = arena_alloc(codegen->arena, sizeof(size_t));
                 *offset = codegen->base_offset;
 
                 map_put(codegen->symbols_stack_offset, symbol_ptr, offset);
-                fprintf(codegen->out, "    mov %%rax, -%ld(%%rbp)\n", codegen->base_offset);
+
+                size_t type_size = type_to_bytes(&symbol->type);
+
+                fprintf(codegen->out,
+                        "    mov %s, -%ld(%%rbp)\n",
+                        get_accumulator_reg_for(type_size),
+                        codegen->base_offset);
+                codegen->base_offset += type_size;
 
                 break;
             }
@@ -419,6 +438,18 @@ codegen_linux_x86_64_emit_block(codegen_x86_64_t *codegen, ast_block_t *block)
     codegen->base_offset = block_offset;
 }
 
+static size_t
+type_to_bytes(type_t *type)
+{
+    switch (type->kind) {
+        case TYPE_PRIMITIVE: {
+            return type->as_primitive.size;
+        }
+    }
+
+    assert(0 && "unreachable");
+}
+
 static size_t
 calculate_fn_local_size(scope_t *scope)
 {
@@ -431,9 +462,8 @@ calculate_fn_local_size(scope_t *scope)
     map_get_kvs(scope->symbols, kvs);
 
     for (size_t i = 0; i < scope->symbols->size; ++i) {
-        // FIXME: symbols must have their types. Since we just have 8bytes
-        //        variables it is hard coded.
-        local_size += 8;
+        symbol_t *symbol = (symbol_t *)kvs[i]->value;
+        local_size += type_to_bytes(&symbol->type);
     }
 
     size_t max_child_local_size = 0;
@@ -456,7 +486,8 @@ calculate_fn_local_size(scope_t *scope)
 static void
 codegen_linux_x86_64_emit_function(codegen_x86_64_t *codegen, ast_fn_definition_t *fn)
 {
-    codegen->base_offset = 0;
+    codegen->base_offset = X86_CALL_EIP_STACK_OFFSET;
+
     ast_node_t *block_node = fn->block;
     fprintf(codegen->out, "" SV_FMT ":\n", SV_ARG(fn->identifier));
 
@@ -464,8 +495,6 @@ codegen_linux_x86_64_emit_function(codegen_x86_64_t *codegen, ast_fn_definition_
 
     size_t local_size = calculate_fn_local_size(fn->scope);
 
-    // TODO: get the local_size from function scope
-
     if (local_size != 0) {
         fprintf(codegen->out, "    sub $%ld, %%rsp\n", local_size);
     }
@@ -475,3 +504,16 @@ codegen_linux_x86_64_emit_function(codegen_x86_64_t *codegen, ast_fn_definition_
 
     codegen_linux_x86_64_emit_block(codegen, &block);
 }
+
+static char *
+get_accumulator_reg_for(size_t bytes)
+{
+    if (bytes <= 1) {
+        return "%ah";
+    } else if (bytes <= 2) {
+        return "%ax";
+    } else if (bytes <= 4) {
+        return "%eax";
+    }
+    return "%rax";
+}
diff --git a/src/type.c b/src/type.c
index cbdfbde..64147a2 100644
--- a/src/type.c
+++ b/src/type.c
@@ -21,12 +21,30 @@ type_t
 type_from_id(string_view_t id)
 {
     type_t type = { 0 };
+    if (string_view_eq_to_cstr(id, "u8")) {
+        type.kind = TYPE_PRIMITIVE;
+        type.as_primitive.size = 1;
+        type.as_primitive.kind = TYPE_U8;
+        return type;
+    }
+    if (string_view_eq_to_cstr(id, "u16")) {
+        type.kind = TYPE_PRIMITIVE;
+        type.as_primitive.size = 2;
+        type.as_primitive.kind = TYPE_U16;
+        return type;
+    }
     if (string_view_eq_to_cstr(id, "u32")) {
         type.kind = TYPE_PRIMITIVE;
         type.as_primitive.size = 4;
         type.as_primitive.kind = TYPE_U32;
         return type;
     }
+    if (string_view_eq_to_cstr(id, "u64")) {
+        type.kind = TYPE_PRIMITIVE;
+        type.as_primitive.size = 8;
+        type.as_primitive.kind = TYPE_U64;
+        return type;
+    }
 
     // FIXME: handle user defined types
     assert(0 && "unknown type");
diff --git a/src/type.h b/src/type.h
index b431171..1da3a11 100644
--- a/src/type.h
+++ b/src/type.h
@@ -24,7 +24,10 @@ typedef enum
 
 typedef enum
 {
-    TYPE_U32
+    TYPE_U8,
+    TYPE_U16,
+    TYPE_U32,
+    TYPE_U64
 } type_primitive_kind_t;
 
 typedef struct type_primitive
diff --git a/tests/integration/tests/0026_primitive_unsigneds.ol b/tests/integration/tests/0026_primitive_unsigneds.ol
new file mode 100644
index 0000000..25f0f7e
--- /dev/null
+++ b/tests/integration/tests/0026_primitive_unsigneds.ol
@@ -0,0 +1,27 @@
+# Copyright (C) 2024 olang mantainers
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+fn main(): u64 {
+  var a: u8 = 255
+  var b: u16 = 65535
+  var c: u32 = 4294967295
+  var d: u64 = 4294967296
+
+  return a + b + c + d - a - b - c - d
+}
+
+# TEST test_compile(exit_code=0)
+
+# TEST test_run_binary(exit_code=0)
-- 
2.34.1