Add BASM generation for `if` expressions

3 files changed, 85 insertions, 37 deletions

diff --git a/src/ir.c b/src/ir.c
index f1b7eb9..86a1a9a 100644
--- a/src/ir.c
+++ b/src/ir.c
@@ -13,8 +13,8 @@ emit_arith(ProgramBASM *program, Node *node,  Operator op) {
     Operand reg_b;
     for (size_t i = 1; i < array_size(node->builtin.args); ++i) {
         Node *arg = node->builtin.args[i];
-        Operand reg_dst = NEW_REG();
         reg_b = emit_basm(program, arg);
+        Operand reg_dst = NEW_REG();
         EMIT_2(program, line, op, reg_dst, reg_a, reg_b);
         reg_a = reg_dst;
     }
@@ -90,14 +90,50 @@ emit_bool(ProgramBASM *program, Node *node) {
     return reg_dst;
 }
 
-// TODO: emit_if
+Operand
+emit_if(ProgramBASM *program, Node *node) {
+    LineInfo line = (LineInfo){.line = node->line, .col = node->col};
+    Operand label_false = NEW_LAB();
+    Operand label_end = NEW_LAB();
+
+    // If type of expression is `void`, there is nothing to return. Don't
+    // generate a new register or copy output.
+    Operand reg_out = (Operand){0};
+    if (node->expr_type != &default_types[TYPE_VOID]) {
+        reg_out = NEW_REG();
+    }
+
+    Operand cond = emit_basm(program, node->ifexpr.cond);
+    EMIT_1(program, line, OP_JMP_FALSE, label_false, cond);
+
+    Operand ret_true = emit_basm(program, node->ifexpr.expr_true);
+    if (node->ifexpr.expr_false != NULL) {
+        if (node->expr_type != &default_types[TYPE_VOID]) {
+            EMIT_1(program, line, OP_CP64, reg_out, ret_true); // TODO: depends on the type of output
+        }
+        EMIT_0(program, line, OP_JMP, label_end);
+        EMIT_0(program, line, OP_LABEL, label_false);
+        Operand ret_false = emit_basm(program, node->ifexpr.expr_false);
+        if (node->expr_type != &default_types[TYPE_VOID]) {
+            EMIT_1(program, line, OP_CP64, reg_out, ret_false); // TODO: depends on the type of output
+        }
+        EMIT_0(program, line, OP_LABEL, label_end);
+    } else {
+        EMIT_0(program, line, OP_LABEL, label_false);
+    }
+
+    return reg_out;
+}
+
 // TODO: emit_and
 // TODO: emit_or
 // TODO: emit_not
-// TODO: emit_global
-// TODO: emit_local
+// TODO: emit_block
 // TODO: emit_procedure
+// TODO: emit_local_vars
+// TODO: emit_param_vars
 // TODO: emit_proc_call
+// TODO: emit_global_vars
 
 Operand
 emit_basm(ProgramBASM *program, Node *node) {
@@ -105,6 +141,7 @@ emit_basm(ProgramBASM *program, Node *node) {
         case NODE_BOOL: { return emit_bool(program, node); } break;
         case NODE_NUMBER: { return emit_number(program, node); } break;
         case NODE_BUILTIN: { return emit_builtin(program, node); } break;
+        case NODE_IF: { return emit_if(program, node); } break;
         default: {
             push_error(ERR_TYPE_BASM, ERR_UNIMPLEMENTED, node->line, node->col);
             return (Operand){0};
diff --git a/src/ir.h b/src/ir.h
index d5b167e..c0ce22a 100644
--- a/src/ir.h
+++ b/src/ir.h
@@ -36,6 +36,8 @@ typedef enum Operator {
     // (Un)conditional jump operations.
     OP_LABEL,
     OP_JMP,
+    OP_JMP_TRUE,
+    OP_JMP_FALSE,
     OP_JMP_EQ,
     OP_JMP_NEQ,
     OP_JMP_GT,
diff --git a/src/viz.c b/src/viz.c
index 3d6a0f7..8e31387 100644
--- a/src/viz.c
+++ b/src/viz.c
@@ -237,39 +237,41 @@ viz_symtables(Scope **scopes) {
 }
 
 static const char* basm_op_str[] = {
-    [OP_ADD]     = "add   ",
-    [OP_SUB]     = "sub   ",
-    [OP_MUL]     = "mul   ",
-    [OP_DIV]     = "div   ",
-    [OP_MOD]     = "mod   ",
-    [OP_LD8]     = "ld8   ",
-    [OP_LD16]    = "ld16  ",
-    [OP_LD32]    = "ld32  ",
-    [OP_LD64]    = "ld64  ",
-    [OP_ST8]     = "st8   ",
-    [OP_ST16]    = "st16  ",
-    [OP_ST32]    = "st32  ",
-    [OP_ST64]    = "st64  ",
-    [OP_CP8]     = "cp8   ",
-    [OP_CP16]    = "cp16  ",
-    [OP_CP32]    = "cp32  ",
-    [OP_CP64]    = "cp64  ",
-    [OP_NOT]     = "not   ",
-    [OP_AND]     = "and   ",
-    [OP_OR]      = "or    ",
-    [OP_XOR]     = "xor   ",
-    [OP_LSHIFT]  = "lshift",
-    [OP_RSHIFT]  = "rshift",
-    [OP_LROT]    = "lrot  ",
-    [OP_RROT]    = "rrot  ",
-    [OP_LABEL]   = "lab   ",
-    [OP_JMP]     = "jmp   ",
-    [OP_JMP_EQ]  = "jeq   ",
-    [OP_JMP_NEQ] = "jne   ",
-    [OP_JMP_GT]  = "jgt   ",
-    [OP_JMP_LT]  = "jlt   ",
-    [OP_JMP_GE]  = "jge   ",
-    [OP_JMP_LE]  = "jle   ",
+    [OP_ADD]        = "add   ",
+    [OP_SUB]        = "sub   ",
+    [OP_MUL]        = "mul   ",
+    [OP_DIV]        = "div   ",
+    [OP_MOD]        = "mod   ",
+    [OP_LD8]        = "ld8   ",
+    [OP_LD16]       = "ld16  ",
+    [OP_LD32]       = "ld32  ",
+    [OP_LD64]       = "ld64  ",
+    [OP_ST8]        = "st8   ",
+    [OP_ST16]       = "st16  ",
+    [OP_ST32]       = "st32  ",
+    [OP_ST64]       = "st64  ",
+    [OP_CP8]        = "cp8   ",
+    [OP_CP16]       = "cp16  ",
+    [OP_CP32]       = "cp32  ",
+    [OP_CP64]       = "cp64  ",
+    [OP_NOT]        = "not   ",
+    [OP_AND]        = "and   ",
+    [OP_OR]         = "or    ",
+    [OP_XOR]        = "xor   ",
+    [OP_LSHIFT]     = "lshift",
+    [OP_RSHIFT]     = "rshift",
+    [OP_LROT]       = "lrot  ",
+    [OP_RROT]       = "rrot  ",
+    [OP_LABEL]      = "lab   ",
+    [OP_JMP]        = "jmp   ",
+    [OP_JMP_TRUE]   = "jt    ",
+    [OP_JMP_FALSE]  = "jf    ",
+    [OP_JMP_EQ]     = "jeq   ",
+    [OP_JMP_NEQ]    = "jne   ",
+    [OP_JMP_GT]     = "jgt   ",
+    [OP_JMP_LT]     = "jlt   ",
+    [OP_JMP_GE]     = "jge   ",
+    [OP_JMP_LE]     = "jle   ",
 };
 
 void
@@ -314,6 +316,13 @@ viz_instruction(Instruction *inst, LineInfo *line) {
             printf(" ");
             viz_operand(inst->dst);
         } break;
+        case OP_JMP_TRUE:
+        case OP_JMP_FALSE: {
+            printf(" ");
+            viz_operand(inst->dst);
+            printf(", ");
+            viz_operand(inst->src_a);
+        } break;
         default: {
             printf(" ");
             viz_operand(inst->dst);