Merge branch 'master' into llvm-integration

5 files changed, 234 insertions, 10 deletions

diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index d44c4d681..ad3c27902 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -7763,6 +7763,99 @@ ExprKind check_expr_base_internal(CheckerContext *c, Operand *o, Ast *node, Type
 
 	case_end;
 
+	case_ast_node(te, TernaryIfExpr, node);
+		Operand cond = {Addressing_Invalid};
+		check_expr(c, &cond, te->cond);
+		node->viral_state_flags |= te->cond->viral_state_flags;
+
+		if (cond.mode != Addressing_Invalid && !is_type_boolean(cond.type)) {
+			error(te->cond, "Non-boolean condition in ternary if expression");
+		}
+
+		Operand x = {Addressing_Invalid};
+		Operand y = {Addressing_Invalid};
+		check_expr_or_type(c, &x, te->x, type_hint);
+		node->viral_state_flags |= te->x->viral_state_flags;
+
+		if (te->y != nullptr) {
+			check_expr_or_type(c, &y, te->y, type_hint);
+			node->viral_state_flags |= te->y->viral_state_flags;
+		} else {
+			error(node, "A ternary expression must have an else clause");
+			return kind;
+		}
+
+		if (x.type == nullptr || x.type == t_invalid ||
+		    y.type == nullptr || y.type == t_invalid) {
+			return kind;
+		}
+
+		convert_to_typed(c, &x, y.type);
+		if (x.mode == Addressing_Invalid) {
+			return kind;
+		}
+		convert_to_typed(c, &y, x.type);
+		if (y.mode == Addressing_Invalid) {
+			x.mode = Addressing_Invalid;
+			return kind;
+		}
+
+		if (!ternary_compare_types(x.type, y.type)) {
+			gbString its = type_to_string(x.type);
+			gbString ets = type_to_string(y.type);
+			error(node, "Mismatched types in ternary if expression, %s vs %s", its, ets);
+			gb_string_free(ets);
+			gb_string_free(its);
+			return kind;
+		}
+
+		Type *type = x.type;
+		if (is_type_untyped_nil(type) || is_type_untyped_undef(type)) {
+			type = y.type;
+		}
+
+		o->type = type;
+		o->mode = Addressing_Value;
+
+		// if (cond.mode == Addressing_Constant && is_type_boolean(cond.type) &&
+		//     x.mode == Addressing_Constant &&
+		//     y.mode == Addressing_Constant) {
+
+		// 	o->mode = Addressing_Constant;
+
+		// 	if (cond.value.value_bool) {
+		// 		o->value = x.value;
+		// 	} else {
+		// 		o->value = y.value;
+		// 	}
+		// }
+
+	case_end;
+
+	case_ast_node(te, TernaryWhenExpr, node);
+		Operand cond = {};
+		check_expr(c, &cond, te->cond);
+		node->viral_state_flags |= te->cond->viral_state_flags;
+
+		if (cond.mode != Addressing_Constant || !is_type_boolean(cond.type)) {
+			error(te->cond, "Expected a constant boolean condition in ternary when expression");
+			return kind;
+		}
+
+		if (cond.value.value_bool) {
+			check_expr_or_type(c, o, te->x, type_hint);
+			node->viral_state_flags |= te->x->viral_state_flags;
+		} else {
+			if (te->y != nullptr) {
+				check_expr_or_type(c, o, te->y, type_hint);
+				node->viral_state_flags |= te->y->viral_state_flags;
+			} else {
+				error(node, "A ternary when expression must have an else clause");
+				return kind;
+			}
+		}
+	case_end;
+
 	case_ast_node(cl, CompoundLit, node);
 		Type *type = type_hint;
 		bool is_to_be_determined_array_count = false;
@@ -9334,6 +9427,22 @@ gbString write_expr_to_string(gbString str, Ast *node) {
 		str = write_expr_to_string(str, te->y);
 	case_end;
 
+	case_ast_node(te, TernaryIfExpr, node);
+		str = write_expr_to_string(str, te->x);
+		str = gb_string_appendc(str, " if ");
+		str = write_expr_to_string(str, te->cond);
+		str = gb_string_appendc(str, " else ");
+		str = write_expr_to_string(str, te->y);
+	case_end;
+
+	case_ast_node(te, TernaryWhenExpr, node);
+		str = write_expr_to_string(str, te->x);
+		str = gb_string_appendc(str, " when ");
+		str = write_expr_to_string(str, te->cond);
+		str = gb_string_appendc(str, " else ");
+		str = write_expr_to_string(str, te->y);
+	case_end;
+
 
 	case_ast_node(pe, ParenExpr, node);
 		str = gb_string_append_rune(str, '(');
diff --git a/src/check_type.cpp b/src/check_type.cpp
index 6194951c9..010b31f03 100644
--- a/src/check_type.cpp
+++ b/src/check_type.cpp
@@ -3454,6 +3454,26 @@ bool check_type_internal(CheckerContext *ctx, Ast *e, Type **type, Type *named_t
 			return true;
 		}
 	case_end;
+
+	case_ast_node(te, TernaryIfExpr, e);
+		Operand o = {};
+		check_expr_or_type(ctx, &o, e);
+		if (o.mode == Addressing_Type) {
+			*type = o.type;
+			set_base_type(named_type, *type);
+			return true;
+		}
+	case_end;
+
+	case_ast_node(te, TernaryWhenExpr, e);
+		Operand o = {};
+		check_expr_or_type(ctx, &o, e);
+		if (o.mode == Addressing_Type) {
+			*type = o.type;
+			set_base_type(named_type, *type);
+			return true;
+		}
+	case_end;
 	}
 
 	*type = t_invalid;
diff --git a/src/ir.cpp b/src/ir.cpp
index 9cd1e2b51..5528ccee8 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -3103,11 +3103,6 @@ irValue *ir_find_or_generate_context_ptr(irProcedure *proc) {
 		return proc->context_stack[proc->context_stack.count-1].value;
 	}
 
-	irBlock *tmp_block = proc->curr_block;
-	proc->curr_block = proc->blocks[0];
-
-	defer (proc->curr_block = tmp_block);
-
 	irValue *c = ir_add_local_generated(proc, t_context, true);
 	ir_push_context_onto_stack(proc, c);
 	ir_emit_store(proc, c, ir_emit_load(proc, proc->module->global_default_context));
@@ -3301,9 +3296,11 @@ void ir_emit_defer_stmts(irProcedure *proc, irDeferExitKind kind, irBlock *block
 	isize i = count;
 	while (i --> 0) {
 		irDefer d = proc->defer_stmts[i];
-		if (proc->context_stack.count >= d.context_stack_count) {
-			proc->context_stack.count = d.context_stack_count;
-		}
+
+		// TODO(bill, 2020-03-05): Why was this added?
+		// if (proc->context_stack.count >= d.context_stack_count) {
+		// 	proc->context_stack.count = d.context_stack_count;
+		// }
 
 		if (kind == irDeferExit_Default) {
 			if (proc->scope_index == d.scope_index &&
@@ -7161,6 +7158,49 @@ irValue *ir_build_expr_internal(irProcedure *proc, Ast *expr) {
 		return ir_emit(proc, ir_instr_phi(proc, edges, type));
 	case_end;
 
+	case_ast_node(te, TernaryIfExpr, expr);
+		ir_emit_comment(proc, str_lit("TernaryIfExpr"));
+
+		auto edges = array_make<irValue *>(ir_allocator(), 0, 2);
+
+		GB_ASSERT(te->y != nullptr);
+		irBlock *then  = ir_new_block(proc, nullptr, "if.then");
+		irBlock *done  = ir_new_block(proc, nullptr, "if.done"); // NOTE(bill): Append later
+		irBlock *else_ = ir_new_block(proc, nullptr, "if.else");
+
+		irValue *cond = ir_build_cond(proc, te->cond, then, else_);
+		ir_start_block(proc, then);
+
+		Type *type = type_of_expr(expr);
+
+		ir_open_scope(proc);
+		array_add(&edges, ir_emit_conv(proc, ir_build_expr(proc, te->x), type));
+		ir_close_scope(proc, irDeferExit_Default, nullptr);
+
+		ir_emit_jump(proc, done);
+		ir_start_block(proc, else_);
+
+		ir_open_scope(proc);
+		array_add(&edges, ir_emit_conv(proc, ir_build_expr(proc, te->y), type));
+		ir_close_scope(proc, irDeferExit_Default, nullptr);
+
+		ir_emit_jump(proc, done);
+		ir_start_block(proc, done);
+
+		return ir_emit(proc, ir_instr_phi(proc, edges, type));
+	case_end;
+
+	case_ast_node(te, TernaryWhenExpr, expr);
+		TypeAndValue tav = type_and_value_of_expr(te->cond);
+		GB_ASSERT(tav.mode == Addressing_Constant);
+		GB_ASSERT(tav.value.kind == ExactValue_Bool);
+		if (tav.value.value_bool) {
+			return ir_build_expr(proc, te->x);
+		} else {
+			return ir_build_expr(proc, te->y);
+		}
+	case_end;
+
 	case_ast_node(ta, TypeAssertion, expr);
 		TokenPos pos = ast_token(expr).pos;
 		Type *type = tv.type;
diff --git a/src/parser.cpp b/src/parser.cpp
index f89b5676b..83ae9743f 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -35,6 +35,8 @@ Token ast_token(Ast *node) {
 	case Ast_FieldValue:         return node->FieldValue.eq;
 	case Ast_DerefExpr:          return node->DerefExpr.op;
 	case Ast_TernaryExpr:        return ast_token(node->TernaryExpr.cond);
+	case Ast_TernaryIfExpr:      return ast_token(node->TernaryIfExpr.x);
+	case Ast_TernaryWhenExpr:    return ast_token(node->TernaryWhenExpr.x);
 	case Ast_TypeAssertion:      return ast_token(node->TypeAssertion.expr);
 	case Ast_TypeCast:           return node->TypeCast.token;
 	case Ast_AutoCast:           return node->AutoCast.token;
@@ -198,6 +200,16 @@ Ast *clone_ast(Ast *node) {
 		n->TernaryExpr.x    = clone_ast(n->TernaryExpr.x);
 		n->TernaryExpr.y    = clone_ast(n->TernaryExpr.y);
 		break;
+	case Ast_TernaryIfExpr:
+		n->TernaryIfExpr.x    = clone_ast(n->TernaryIfExpr.x);
+		n->TernaryIfExpr.cond = clone_ast(n->TernaryIfExpr.cond);
+		n->TernaryIfExpr.y    = clone_ast(n->TernaryIfExpr.y);
+		break;
+	case Ast_TernaryWhenExpr:
+		n->TernaryWhenExpr.x    = clone_ast(n->TernaryWhenExpr.x);
+		n->TernaryWhenExpr.cond = clone_ast(n->TernaryWhenExpr.cond);
+		n->TernaryWhenExpr.y    = clone_ast(n->TernaryWhenExpr.y);
+		break;
 	case Ast_TypeAssertion:
 		n->TypeAssertion.expr = clone_ast(n->TypeAssertion.expr);
 		n->TypeAssertion.type = clone_ast(n->TypeAssertion.type);
@@ -638,6 +650,21 @@ Ast *ast_ternary_expr(AstFile *f, Ast *cond, Ast *x, Ast *y) {
 	result->TernaryExpr.y = y;
 	return result;
 }
+Ast *ast_ternary_if_expr(AstFile *f, Ast *x, Ast *cond, Ast *y) {
+	Ast *result = alloc_ast_node(f, Ast_TernaryIfExpr);
+	result->TernaryIfExpr.x = x;
+	result->TernaryIfExpr.cond = cond;
+	result->TernaryIfExpr.y = y;
+	return result;
+}
+Ast *ast_ternary_when_expr(AstFile *f, Ast *x, Ast *cond, Ast *y) {
+	Ast *result = alloc_ast_node(f, Ast_TernaryWhenExpr);
+	result->TernaryWhenExpr.x = x;
+	result->TernaryWhenExpr.cond = cond;
+	result->TernaryWhenExpr.y = y;
+	return result;
+}
+
 Ast *ast_type_assertion(AstFile *f, Ast *expr, Token dot, Ast *type) {
 	Ast *result = alloc_ast_node(f, Ast_TypeAssertion);
 	result->TypeAssertion.expr = expr;
@@ -1199,6 +1226,8 @@ Token expect_operator(AstFile *f) {
 	Token prev = f->curr_token;
 	if ((prev.kind == Token_in || prev.kind == Token_not_in) && (f->expr_level >= 0 || f->allow_in_expr)) {
 		// okay
+	} else if (prev.kind == Token_if || prev.kind == Token_when) {
+		// okay
 	} else if (!gb_is_between(prev.kind, Token__OperatorBegin+1, Token__OperatorEnd-1)) {
 		syntax_error(f->curr_token, "Expected an operator, got '%.*s'",
 		             LIT(token_strings[prev.kind]));
@@ -2512,6 +2541,8 @@ bool is_ast_range(Ast *expr) {
 i32 token_precedence(AstFile *f, TokenKind t) {
 	switch (t) {
 	case Token_Question:
+	case Token_if:
+	case Token_when:
 		return 1;
 	case Token_Ellipsis:
 	case Token_RangeHalf:
@@ -2565,6 +2596,14 @@ Ast *parse_binary_expr(AstFile *f, bool lhs, i32 prec_in) {
 				// NOTE(bill): This will also catch operators that are not valid "binary" operators
 				break;
 			}
+			if (op.kind == Token_if || op.kind == Token_when) {
+				Token prev = f->prev_token;
+				if (prev.pos.line < op.pos.line) {
+					// NOTE(bill): Check to see if the `if` or `when` is on the same line of the `lhs` condition
+					break;
+				}
+			}
+
 			expect_operator(f); // NOTE(bill): error checks too
 
 			if (op.kind == Token_Question) {
@@ -2574,6 +2613,20 @@ Ast *parse_binary_expr(AstFile *f, bool lhs, i32 prec_in) {
 				Token token_c = expect_token(f, Token_Colon);
 				Ast *y = parse_expr(f, lhs);
 				expr = ast_ternary_expr(f, cond, x, y);
+			} else if (op.kind == Token_if) {
+				Ast *x = expr;
+				// Token_if
+				Ast *cond = parse_expr(f, lhs);
+				Token tok_else = expect_token(f, Token_else);
+				Ast *y = parse_expr(f, lhs);
+				expr = ast_ternary_if_expr(f, x, cond, y);
+			} else if (op.kind == Token_when) {
+				Ast *x = expr;
+				// Token_when
+				Ast *cond = parse_expr(f, lhs);
+				Token tok_else = expect_token(f, Token_else);
+				Ast *y = parse_expr(f, lhs);
+				expr = ast_ternary_when_expr(f, x, cond, y);
 			} else {
 				Ast *right = parse_binary_expr(f, false, prec+1);
 				if (right == nullptr) {
diff --git a/src/parser.hpp b/src/parser.hpp
index decdd319a..129f1d41b 100644
--- a/src/parser.hpp
+++ b/src/parser.hpp
@@ -283,8 +283,10 @@ AST_KIND(_ExprBegin,  "",  bool) \
 		Token        ellipsis; \
 		ProcInlining inlining; \
 	}) \
-	AST_KIND(FieldValue,    "field value",         struct { Token eq; Ast *field, *value; }) \
-	AST_KIND(TernaryExpr,   "ternary expression",  struct { Ast *cond, *x, *y; }) \
+	AST_KIND(FieldValue,      "field value",              struct { Token eq; Ast *field, *value; }) \
+	AST_KIND(TernaryExpr,     "ternary expression",       struct { Ast *cond, *x, *y; }) \
+	AST_KIND(TernaryIfExpr,   "ternary if expression",    struct { Ast *x, *cond, *y; }) \
+	AST_KIND(TernaryWhenExpr, "ternary when expression",  struct { Ast *x, *cond, *y; }) \
 	AST_KIND(TypeAssertion, "type assertion",      struct { Ast *expr; Token dot; Ast *type; }) \
 	AST_KIND(TypeCast,      "type cast",           struct { Token token; Ast *type, *expr; }) \
 	AST_KIND(AutoCast,      "auto_cast",           struct { Token token; Ast *expr; }) \