Add if/else/elseif/while, including the final assembly

1 files changed, 110 insertions, 52 deletions

diff --git a/src/ssa/ssa.c b/src/ssa/ssa.c
index 940f636..5c625b2 100644
--- a/src/ssa/ssa.c
+++ b/src/ssa/ssa.c
@@ -69,6 +69,7 @@ int ssa_init(Ssa *self, Parser *parser) {
     self->reg_counter = 0;
     self->param_counter = 0;
     self->func_counter = 0;
+    self->label_counter = 0;
     self->parser = parser;
     return 0;
 }
@@ -80,6 +81,7 @@ static CHECK_RESULT int ssa_get_unique_reg(Ssa *self, SsaRegister *result) {
         amal_log_error("Ssa too many registers!");
         return -1;
     }
+    assert(self->reg_counter <= INT8_MAX && "TODO: Implement usage of reg higher than 128");
     *result = self->reg_counter++;
     return 0;
 }
@@ -331,24 +333,33 @@ static CHECK_RESULT int ssa_ins_call_extern(Ssa *self, SsaExternFuncIndex extern
     return buffer_append(&self->instructions, &ins_func_call_extern, sizeof(ins_func_call_extern));
 }
 
-static CHECK_RESULT int ssa_ins_jumpzero(Ssa *self, SsaRegister condition_reg, JumpOffset jump_offset) {
+static CHECK_RESULT int ssa_ins_jumpzero(Ssa *self, SsaRegister condition_reg, SsaLabelIndex target_label, usize *instruction_offset) {
     const u8 ins_type = SSA_JUMP_ZERO;
     SsaInsJumpZero ins_jump_zero;
     ins_jump_zero.condition_reg = condition_reg;
-    ins_jump_zero.jump_offset = jump_offset;
-    if(jump_offset == 0)
+    ins_jump_zero.target_label = target_label;
+    if(target_label == 0)
         amal_log_debug("JUMP_ZERO r%d, DUMMY", condition_reg);
     else
-        amal_log_debug("JUMP_ZERO r%d, %d", condition_reg, jump_offset);
+        amal_log_debug("JUMP_ZERO r%d, l%d", condition_reg, target_label);
+    *instruction_offset = self->instructions.size;
     return_if_error(buffer_append(&self->instructions, &ins_type, 1));
     return buffer_append(&self->instructions, &ins_jump_zero, sizeof(ins_jump_zero));
 }
 
-static CHECK_RESULT int ssa_ins_jump(Ssa *self, JumpOffset jump_offset) {
+static CHECK_RESULT int ssa_ins_jump(Ssa *self, SsaLabelIndex target_label, usize *instruction_offset) {
     const u8 ins_type = SSA_JUMP;
     SsaInsJump ins_jump;
-    ins_jump.jump_offset = jump_offset;
-    amal_log_debug("JUMP %d", jump_offset);
+    ins_jump.target_label = target_label;
+
+    if(target_label == 0)
+        amal_log_debug("JUMP DUMMY");
+    else
+        amal_log_debug("JUMP l%d", target_label);
+
+    if(instruction_offset)
+        *instruction_offset = self->instructions.size;
+
     return_if_error(buffer_append(&self->instructions, &ins_type, 1));
     return buffer_append(&self->instructions, &ins_jump, sizeof(ins_jump));
 }
@@ -359,21 +370,28 @@ static CHECK_RESULT int ssa_ins_return(Ssa *self, SsaRegister reg) {
     return buffer_append(&self->instructions, &reg, sizeof(reg));
 }
 
-static usize ssa_ins_get_index(Ssa *self) {
-    return self->instructions.size;
+static CHECK_RESULT int ssa_ins_label(Ssa *self, u16 *label_index) {
+    const u8 ins_type = SSA_LABEL;
+    /* Overflow */
+    if(self->label_counter + 1 <= self->label_counter) {
+        amal_log_error("Ssa too many labels!");
+        return -1;
+    }
+    *label_index = self->label_counter;
+    ++self->label_counter;
+    return buffer_append(&self->instructions, &ins_type, 1);
 }
 
-/* Set target of jump instruction to current location */
-static CHECK_RESULT int ssa_ins_jump_set_target(Ssa *self, usize jump_ins_index) {
+static CHECK_RESULT int ssa_set_jump_label(Ssa *self, usize jump_ins_index, SsaLabelIndex label) {
     switch(self->instructions.data[jump_ins_index]) {
         case SSA_JUMP_ZERO: {
-            isize jump_offset = (isize)ssa_ins_get_index(self) - (isize)jump_ins_index;
-            /* TODO: Should something be done about this? */
-            if(jump_offset < -0x7FFF || jump_offset > 0x7FFF) {
-                amal_log_error("Unexpected error. Jump offset has to be less than +-32767, was %d", jump_offset);
-                return -1;
-            }
-            am_memcpy(self->instructions.data + jump_ins_index + 1 + offsetof(SsaInsJumpZero, jump_offset), &jump_offset, sizeof(JumpOffset));
+            /* +1 to skip instruction opcode */
+            am_memcpy(self->instructions.data + jump_ins_index + 1 + offsetof(SsaInsJumpZero, target_label), &label, sizeof(SsaLabelIndex));
+            break;
+        }
+        case SSA_JUMP: {
+            /* +1 to skip instruction opcode */
+            am_memcpy(self->instructions.data + jump_ins_index + 1 + offsetof(SsaInsJump, target_label), &label, sizeof(SsaLabelIndex));
             break;
         }
         default:
@@ -386,6 +404,7 @@ static CHECK_RESULT int ssa_ins_jump_set_target(Ssa *self, usize jump_ins_index)
 static CHECK_RESULT SsaRegister ast_generate_ssa(Ast *self, SsaCompilerContext *context);
 static CHECK_RESULT SsaRegister scope_named_object_generate_ssa(ScopeNamedObject *self, SsaCompilerContext *context);
 
+#if 0
 static bool ast_resolved_type_is_decl(AstResolvedType *self) {
     /* TODO: Add more types as they are introduced */
     LhsExpr *lhs_expr;
@@ -406,6 +425,24 @@ static bool ast_resolved_type_is_decl(AstResolvedType *self) {
     assert(lhs_expr->rhs_expr);
     return lhs_expr->rhs_expr->type == AST_FUNCTION_DECL || lhs_expr->rhs_expr->type == AST_STRUCT_DECL;
 }
+#endif
+static bool lhs_expr_is_decl(LhsExpr *self) {
+    if(self->rhs_expr) {
+        return self->rhs_expr->type == AST_FUNCTION_DECL || self->rhs_expr->type == AST_STRUCT_DECL;
+    } else {
+        switch(self->type.type) {
+            case VARIABLE_TYPE_NONE:
+                assert(bool_false);
+                return 0;
+            case VARIABLE_TYPE_VARIABLE:
+                return bool_false;
+            case VARIABLE_TYPE_SIGNATURE:
+                /* TODO: This should return bool_false when it's possible to use signature in expressions */
+                return bool_true;
+        }
+        return 0;
+    }
+}
 
 static CHECK_RESULT SsaRegister number_generate_ssa(Number *self, SsaCompilerContext *context) {
     SsaRegister reg;
@@ -482,7 +519,7 @@ static CHECK_RESULT SsaRegister lhsexpr_generate_ssa(LhsExpr *self, AstResolveDa
             Import expression also has no meaning in SSA until it's used.
             TODO: Shouldn't lhsexpr that have struct/function declaration as rhs be different ast expression types?
         */
-        if(ast_resolved_type_is_decl(&resolve_data->type) || rhs_expr->type == AST_IMPORT) {
+        if(lhs_expr_is_decl(self) || rhs_expr->type == AST_IMPORT) {
             /*assert(bool_false);*/
             return 0;
         }
@@ -528,6 +565,7 @@ static CHECK_RESULT SsaRegister function_parameter_generate_ssa(FunctionParamete
         throw(-1);
     }
     reg = -1 - reg;
+    assert(reg >= INT8_MIN && "TODO: Implement more than 128 params");
     self->resolve_data.status = AST_SSA_RESOLVED;
     self->resolve_data.ssa_reg = reg;
     return reg;
@@ -555,10 +593,9 @@ static CHECK_RESULT SsaRegister funcdecl_generate_ssa(FunctionDecl *self, SsaCom
         that is reset after function end
     */
     usize func_metadata_index;
-    SsaRegister prev_reg_counter = context->ssa->reg_counter;
-    SsaRegister prev_param_counter = context->ssa->param_counter;
     u8 func_flags = 0;
     context->ssa->reg_counter = 0;
+    context->ssa->label_counter = 0;
 
     /* 
         Parameters need to have generated ssa so the first ssa registers belong to the function.
@@ -580,9 +617,6 @@ static CHECK_RESULT SsaRegister funcdecl_generate_ssa(FunctionDecl *self, SsaCom
 
     /* Add the number of registers used to the function metadata (FUNC_START) */
     am_memcpy(context->ssa->instructions.data + func_metadata_index, &context->ssa->reg_counter, sizeof(u16));
-
-    context->ssa->param_counter = prev_param_counter;
-    context->ssa->reg_counter = prev_reg_counter;
     return 0;
 }
 
@@ -684,47 +718,71 @@ static CHECK_RESULT SsaRegister binop_generate_ssa(Binop *self, SsaCompilerConte
     return reg;
 }
 
-static void else_if_statement_generate_ssa(ElseIfStatement *else_if_stmt, SsaCompilerContext *context) {
-    usize jump_ins_index = 0;
+static void else_if_statement_generate_ssa(ElseIfStatement *else_if_stmt, SsaCompilerContext *context, SsaLabelIndex *skip_other_else_statements_label) {
     if(else_if_stmt->condition) {
-        SsaRegister condition_reg;
-        condition_reg = ast_generate_ssa(else_if_stmt->condition, context);
-        jump_ins_index = ssa_ins_get_index(context->ssa);
-        throw_if_error(ssa_ins_jumpzero(context->ssa, condition_reg, 0));
+        usize jump_ins_index;
+        usize jump_skip_else_index;
+        SsaLabelIndex skip_body_label;
+        SsaRegister condition_reg =  ast_generate_ssa(else_if_stmt->condition, context);
+        throw_if_error(ssa_ins_jumpzero(context->ssa, condition_reg, 0, &jump_ins_index));
+        scope_generate_ssa(&else_if_stmt->body, context);
+        if(else_if_stmt->next_else_if_stmt)
+            throw_if_error(ssa_ins_jump(context->ssa, 0, &jump_skip_else_index));
+
+        throw_if_error(ssa_ins_label(context->ssa, &skip_body_label));
+        throw_if_error(ssa_set_jump_label(context->ssa, jump_ins_index, skip_body_label));
+        if(else_if_stmt->next_else_if_stmt) {
+            else_if_statement_generate_ssa(else_if_stmt->next_else_if_stmt, context, skip_other_else_statements_label);
+            /* Skip over all other else if statements, since else_if_statement_generate_ssa is recursive */
+            throw_if_error(ssa_set_jump_label(context->ssa, jump_skip_else_index, *skip_other_else_statements_label));
+            return;
+        }
+    } else {
+        assert(!else_if_stmt->next_else_if_stmt);
+        scope_generate_ssa(&else_if_stmt->body, context);
     }
-    scope_generate_ssa(&else_if_stmt->body, context);
-    if(else_if_stmt->condition)
-        throw_if_error(ssa_ins_jump_set_target(context->ssa, jump_ins_index));
-    if(else_if_stmt->next_else_if_stmt)
-        else_if_statement_generate_ssa(else_if_stmt->next_else_if_stmt, context);
+
+    /* Note: The last else if statement doesn't need a jump */
+    throw_if_error(ssa_ins_label(context->ssa, skip_other_else_statements_label));
 }
 
 static void if_statement_generate_ssa(IfStatement *if_stmt, SsaCompilerContext *context) {
+    usize jump_ins_index;
+    usize jump_skip_else_index;
+    SsaLabelIndex skip_body_label;
+    SsaLabelIndex skip_else_statements_label;
+
     SsaRegister condition_reg = ast_generate_ssa(if_stmt->condition, context);
-    usize jump_ins_index = ssa_ins_get_index(context->ssa);
-    throw_if_error(ssa_ins_jumpzero(context->ssa, condition_reg, 0));
+    throw_if_error(ssa_ins_jumpzero(context->ssa, condition_reg, 0, &jump_ins_index));
     scope_generate_ssa(&if_stmt->body, context);
-    throw_if_error(ssa_ins_jump_set_target(context->ssa, jump_ins_index));
     if(if_stmt->else_if_stmt)
-        else_if_statement_generate_ssa(if_stmt->else_if_stmt, context);
+        throw_if_error(ssa_ins_jump(context->ssa, 0, &jump_skip_else_index));
+
+    throw_if_error(ssa_ins_label(context->ssa, &skip_body_label));
+    throw_if_error(ssa_set_jump_label(context->ssa, jump_ins_index, skip_body_label));
+    if(if_stmt->else_if_stmt) {
+        else_if_statement_generate_ssa(if_stmt->else_if_stmt, context, &skip_else_statements_label);
+        /*
+            Skip over all else if statements, since else_if_statement_generate_ssa is recursive.
+            We want to jump since we want to skip the else if statements if we are inside the first if-statement
+        */
+        throw_if_error(ssa_set_jump_label(context->ssa, jump_skip_else_index, skip_else_statements_label));
+    }
 }
 
 static void while_statement_generate_ssa(WhileStatement *while_stmt, SsaCompilerContext *context) {
-    isize jump_offset;
-    usize jump_back_ins_index = ssa_ins_get_index(context->ssa);
+    SsaLabelIndex before_condition_label;
+    SsaLabelIndex skip_body_label;
+    usize jump_after_condition_index;
+
+    throw_if_error(ssa_ins_label(context->ssa, &before_condition_label));
     SsaRegister condition_reg = ast_generate_ssa(while_stmt->condition, context);
-    usize jump_condition_ins_index = ssa_ins_get_index(context->ssa);
-    throw_if_error(ssa_ins_jumpzero(context->ssa, condition_reg, 0));
+    throw_if_error(ssa_ins_jumpzero(context->ssa, condition_reg, 0, &jump_after_condition_index));
     scope_generate_ssa(&while_stmt->body, context);
-    /* Jump back and check condition again before running the content of the loop again */
-    jump_offset = (isize)jump_back_ins_index - (isize)ssa_ins_get_index(context->ssa);
-    /* TODO: Should something be done about this? */
-    if(jump_offset < -0x7FFF || jump_offset > 0x7FFF) {
-        amal_log_error("Unexpected error. Jump offset has to be less than +-32767, was %d", jump_offset);
-        throw(1);
-    }
-    throw_if_error(ssa_ins_jump(context->ssa, (JumpOffset)jump_offset));
-    throw_if_error(ssa_ins_jump_set_target(context->ssa, jump_condition_ins_index));
+
+    throw_if_error(ssa_ins_jump(context->ssa, before_condition_label, NULL));
+    throw_if_error(ssa_ins_label(context->ssa, &skip_body_label));
+    throw_if_error(ssa_set_jump_label(context->ssa, jump_after_condition_index, skip_body_label));
 }
 
 static void return_expr_generate_ssa(ReturnExpr *self, SsaCompilerContext *context) {