From fc4e8cb350c19cd0ffa3a08a5b634e4c2cdd96cd Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Tue, 1 Oct 2024 14:13:16 +0900
Subject: [PATCH] [qfcc] Switch to deferred expressions for glsl

I plan to do this eventually for Ruamoko, but I need it to keep working
for now; it's rather nice having multiple languages. I expect this will
open up a lot of options for inlining, generic/template function
instantiation, etc. Right now, it's helping with specialization
constants in glsl.
---
 tools/qfcc/include/expr.h            |  19 +++++
 tools/qfcc/include/expr_names.h      |   2 +
 tools/qfcc/source/Makemodule.am      |   1 +
 tools/qfcc/source/expr.c             |  40 ++++++++++
 tools/qfcc/source/expr_assign.c      |   4 +
 tools/qfcc/source/expr_dag.c         |   8 ++
 tools/qfcc/source/expr_process.c     | 115 +++++++++++++++++++++++++++
 tools/qfcc/source/glsl-declaration.c |   3 +
 tools/qfcc/source/glsl-parse.y       |  43 +++++-----
 9 files changed, 214 insertions(+), 21 deletions(-)
 create mode 100644 tools/qfcc/source/expr_process.c

diff --git a/tools/qfcc/include/expr.h b/tools/qfcc/include/expr.h
index c299253b4..c5c1cb960 100644
--- a/tools/qfcc/include/expr.h
+++ b/tools/qfcc/include/expr.h
@@ -321,6 +321,18 @@ typedef struct {
 	const symbol_t *sym;
 } ex_type_t;
 
+typedef struct {
+	int         op;
+	bool        postop;
+	const expr_t *expr;
+} ex_incop_t;
+
+typedef struct {
+	const expr_t *test;
+	const expr_t *true_expr;
+	const expr_t *false_expr;
+} ex_cond_t;
+
 #define POINTER_VAL(p) (((p).def ? (p).def->offset : 0) + (p).val)
 
 typedef struct expr_s {
@@ -364,6 +376,8 @@ typedef struct expr_s {
 		ex_extend_t extend;				///< vector extend operation
 		ex_multivec_t multivec;			///< geometric algebra multivector
 		ex_type_t typ;					///< type expression
+		ex_incop_t incop;				///< incop expression
+		ex_cond_t cond;					///< ?: conditional expression
 	};
 } expr_t;
 
@@ -872,6 +886,9 @@ expr_t *new_assign_expr (const expr_t *dst, const expr_t *src);
 expr_t *new_return_expr (const expr_t *ret_val);
 expr_t *new_adjstk_expr (int mode, int offset);
 expr_t *new_with_expr (int mode, int reg, const expr_t *val);
+expr_t *new_incop_expr (int op, const expr_t *e, bool postop);
+expr_t *new_cond_expr (const expr_t *test, const expr_t *true_expr,
+					   const expr_t *false_expr);
 
 /**	Create an expression of the correct type that references the specified
 	parameter slot.
@@ -1003,6 +1020,8 @@ void scatter_factors (const expr_t *prod, const expr_t **factors);
 const expr_t *gather_factors (const type_t *type, int op,
 							  const expr_t **factors, int count);
 
+const expr_t *expr_process (const expr_t *expr);
+
 ///@}
 
 #endif//__expr_h
diff --git a/tools/qfcc/include/expr_names.h b/tools/qfcc/include/expr_names.h
index 6061104fa..23492aa00 100644
--- a/tools/qfcc/include/expr_names.h
+++ b/tools/qfcc/include/expr_names.h
@@ -69,6 +69,8 @@ EX_EXPR(extend)		///< vector extend operation (::ex_extend_t)
 EX_EXPR(multivec)	///< geometric algebra multivector (::ex_multivec_t)
 EX_EXPR(list)		///< non-invasive list of expressions (::ex_list_t)
 EX_EXPR(type)		///< type expression for generics
+EX_EXPR(incop)		///< pre or post increment/decrement (::ex_incop_t)
+EX_EXPR(cond)		///< ?: conditional expression (::ex_cond_t)
 
 #undef EX_EXPR
 
diff --git a/tools/qfcc/source/Makemodule.am b/tools/qfcc/source/Makemodule.am
index e83365d02..7fa3eb954 100644
--- a/tools/qfcc/source/Makemodule.am
+++ b/tools/qfcc/source/Makemodule.am
@@ -36,6 +36,7 @@ qfcc_SOURCES = \
 	tools/qfcc/source/expr_dag.c \
 	tools/qfcc/source/expr_obj.c \
 	tools/qfcc/source/expr_optimize.c \
+	tools/qfcc/source/expr_process.c \
 	tools/qfcc/source/expr_type.c \
 	tools/qfcc/source/expr_unary.c \
 	tools/qfcc/source/expr_vector.c \
diff --git a/tools/qfcc/source/expr.c b/tools/qfcc/source/expr.c
index 0e30a7d59..03cdc6087 100644
--- a/tools/qfcc/source/expr.c
+++ b/tools/qfcc/source/expr.c
@@ -206,6 +206,12 @@ get_type (const expr_t *e)
 			return 0;
 		case ex_type:
 			return nullptr;
+		case ex_incop:
+			return get_type (e->incop.expr);
+		case ex_cond:
+			//FIXME true_expr and false_expr need to have the same type,
+			//unless one is nil
+			return get_type (e->cond.true_expr);
 		case ex_count:
 			internal_error (e, "invalid expression");
 	}
@@ -1934,6 +1940,12 @@ has_function_call (const expr_t *e)
 				}
 			}
 			return 0;
+		case ex_incop:
+			return has_function_call (e->incop.expr);
+		case ex_cond:
+			return (has_function_call (e->cond.test)
+					|| has_function_call (e->cond.true_expr)
+					|| has_function_call (e->cond.false_expr));
 		case ex_count:
 			break;
 	}
@@ -2463,6 +2475,34 @@ conditional_expr (const expr_t *cond, const expr_t *e1, const expr_t *e2)
 	return block;
 }
 
+expr_t *
+new_incop_expr (int op, const expr_t *e, bool postop)
+{
+	auto incop = new_expr ();
+	incop->type = ex_incop;
+	incop->incop = (ex_incop_t) {
+		.op = op,
+		.postop = postop,
+		.expr = e,
+	};
+	return incop;
+}
+
+expr_t *
+new_cond_expr (const expr_t *test, const expr_t *true_expr,
+			   const expr_t *false_expr)
+{
+	auto cond = new_expr ();
+	cond->type = ex_cond;
+	cond->cond = (ex_cond_t) {
+		.test = test,
+		.true_expr = true_expr,
+		.false_expr = false_expr,
+	};
+	return cond;
+}
+
+
 const expr_t *
 incop_expr (int op, const expr_t *e, int postop)
 {
diff --git a/tools/qfcc/source/expr_assign.c b/tools/qfcc/source/expr_assign.c
index f62da1b1c..9e96525dd 100644
--- a/tools/qfcc/source/expr_assign.c
+++ b/tools/qfcc/source/expr_assign.c
@@ -131,7 +131,11 @@ is_lvalue (const expr_t *expr)
 		case ex_multivec:
 		case ex_list:
 		case ex_type:
+		case ex_incop:
 			break;
+		case ex_cond:
+			return (is_lvalue (expr->cond.true_expr)
+					&& is_lvalue (expr->cond.false_expr));
 		case ex_count:
 			internal_error (expr, "invalid expression");
 	}
diff --git a/tools/qfcc/source/expr_dag.c b/tools/qfcc/source/expr_dag.c
index 52132ec88..b46b17583 100644
--- a/tools/qfcc/source/expr_dag.c
+++ b/tools/qfcc/source/expr_dag.c
@@ -78,6 +78,7 @@ edag_add_expr (const expr_t *expr)
 			case ex_with:
 			case ex_args:
 			case ex_type:
+			case ex_incop:
 				// these are never put in the dag
 				return expr;
 			case ex_list:
@@ -181,6 +182,13 @@ edag_add_expr (const expr_t *expr)
 				break;
 			case ex_multivec:
 				return expr;	//FIXME ?
+			case ex_cond:
+				if (e->cond.test == expr->cond.test
+					&& e->cond.true_expr == expr->cond.true_expr
+					&& e->cond.false_expr == expr->cond.false_expr) {
+					return e;
+				}
+				break;
 		}
 	}
 	DARRAY_APPEND (&expr_dag, expr);
diff --git a/tools/qfcc/source/expr_process.c b/tools/qfcc/source/expr_process.c
new file mode 100644
index 000000000..eb3e0b43d
--- /dev/null
+++ b/tools/qfcc/source/expr_process.c
@@ -0,0 +1,115 @@
+/*
+	expr_process.c
+
+	expression processing
+
+	Copyright (C) 2024 Bill Currie <bill@taniwha.org>
+
+	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 2
+	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, write to:
+
+		Free Software Foundation, Inc.
+		59 Temple Place - Suite 330
+		Boston, MA  02111-1307, USA
+
+*/
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+#include <string.h>
+
+#include "QF/fbsearch.h"
+#include "QF/heapsort.h"
+#include "QF/math/bitop.h"
+
+#include "tools/qfcc/include/algebra.h"
+#include "tools/qfcc/include/diagnostic.h"
+#include "tools/qfcc/include/expr.h"
+#include "tools/qfcc/include/rua-lang.h"
+#include "tools/qfcc/include/symtab.h"
+#include "tools/qfcc/include/type.h"
+#include "tools/qfcc/include/value.h"
+
+typedef const expr_t *(*process_f) (const expr_t *expr);
+
+static const expr_t *
+proc_expr (const expr_t *expr)
+{
+	auto e1 = expr_process (expr->expr.e1);
+	auto e2 = expr_process (expr->expr.e2);
+	if (is_error (e1)) {
+		return e1;
+	}
+	if (is_error (e2)) {
+		return e2;
+	}
+
+	return binary_expr (expr->expr.op, e1, e2);
+}
+
+static const expr_t *
+proc_uexpr (const expr_t *expr)
+{
+	auto e1 = expr_process (expr->expr.e1);
+	if (is_error (e1)) {
+		return e1;
+	}
+
+	return unary_expr (expr->expr.op, e1);
+}
+
+static const expr_t *
+proc_symbol (const expr_t *expr)
+{
+	return expr;
+}
+
+static const expr_t *
+proc_value (const expr_t *expr)
+{
+	return expr;
+}
+
+static const expr_t *
+proc_compound (const expr_t *expr)
+{
+	auto comp = new_compound_init ();
+	for (auto ele = expr->compound.head; ele; ele = ele->next) {
+		append_element (comp, new_element (expr_process (ele->expr),
+										   ele->designator));
+	}
+	return comp;
+}
+
+const expr_t *
+expr_process (const expr_t *expr)
+{
+	static process_f funcs[ex_count] = {
+		[ex_expr] = proc_expr,
+		[ex_uexpr] = proc_uexpr,
+		[ex_value] = proc_value,
+		[ex_compound] = proc_compound,
+		[ex_symbol] = proc_symbol,
+	};
+
+	if (expr->type >= ex_count) {
+		internal_error (expr, "bad sub-expression type: %d", expr->type);
+	}
+	if (!funcs[expr->type]) {
+		internal_error (expr, "unexpected sub-expression type: %s",
+						expr_names[expr->type]);
+	}
+
+	return funcs[expr->type] (expr);
+}
diff --git a/tools/qfcc/source/glsl-declaration.c b/tools/qfcc/source/glsl-declaration.c
index a22d85162..5351eea13 100644
--- a/tools/qfcc/source/glsl-declaration.c
+++ b/tools/qfcc/source/glsl-declaration.c
@@ -52,6 +52,9 @@ glsl_parse_declaration (specifier_t spec, symbol_t *sym, const type_t *array,
 		spec.type = append_type (array, spec.type);
 		spec.type = find_type (spec.type);
 	}
+	if (init) {
+		init = expr_process (init);
+	}
 	auto attributes = glsl_optimize_attributes (spec.attributes);
 	if (sym && sym->sy_type == sy_expr) {
 		auto id_list = sym->expr;
diff --git a/tools/qfcc/source/glsl-parse.y b/tools/qfcc/source/glsl-parse.y
index 26132d869..fedffde28 100644
--- a/tools/qfcc/source/glsl-parse.y
+++ b/tools/qfcc/source/glsl-parse.y
@@ -403,7 +403,7 @@ function_identifier
 unary_expression
 	: postfix_expression
 	| INCOP unary_expression			{ $$ = incop_expr ($1, $2, 0); }
-	| unary_operator unary_expression	{ $$ = unary_expr ($1, $2); }
+	| unary_operator unary_expression	{ $$ = new_unary_expr ($1, $2); }
 	;
 
 unary_operator
@@ -417,15 +417,15 @@ multiplicative_expression
 	: unary_expression
 	| multiplicative_expression '*' unary_expression
 		{
-			$$ = binary_expr ('*', $1, $3);
+			$$ = new_binary_expr ('*', $1, $3);
 		}
 	| multiplicative_expression '/' unary_expression
 		{
-			$$ = binary_expr ('/', $1, $3);
+			$$ = new_binary_expr ('/', $1, $3);
 		}
 	| multiplicative_expression '%' unary_expression
 		{
-			$$ = binary_expr ('%', $1, $3);
+			$$ = new_binary_expr ('%', $1, $3);
 		}
 	;
 
@@ -433,11 +433,11 @@ additive_expression
 	: multiplicative_expression
 	| additive_expression '+' multiplicative_expression
 		{
-			$$ = binary_expr ('+', $1, $3);
+			$$ = new_binary_expr ('+', $1, $3);
 		}
 	| additive_expression '-' multiplicative_expression
 		{
-			$$ = binary_expr ('-', $1, $3);
+			$$ = new_binary_expr ('-', $1, $3);
 		}
 	;
 
@@ -445,11 +445,11 @@ shift_expression
 	: additive_expression
 	| shift_expression SHL additive_expression
 		{
-			$$ = binary_expr (QC_SHL, $1, $3);
+			$$ = new_binary_expr (QC_SHL, $1, $3);
 		}
 	| shift_expression SHR additive_expression
 		{
-			$$ = binary_expr (QC_SHR, $1, $3);
+			$$ = new_binary_expr (QC_SHR, $1, $3);
 		}
 	;
 
@@ -457,19 +457,19 @@ relational_expression
 	: shift_expression
 	| relational_expression LT shift_expression
 		{
-			$$ = binary_expr (QC_LT, $1, $3);
+			$$ = new_binary_expr (QC_LT, $1, $3);
 		}
 	| relational_expression GT shift_expression
 		{
-			$$ = binary_expr (QC_GT, $1, $3);
+			$$ = new_binary_expr (QC_GT, $1, $3);
 		}
 	| relational_expression LE shift_expression
 		{
-			$$ = binary_expr (QC_LE, $1, $3);
+			$$ = new_binary_expr (QC_LE, $1, $3);
 		}
 	| relational_expression GE shift_expression
 		{
-			$$ = binary_expr (QC_GE, $1, $3);
+			$$ = new_binary_expr (QC_GE, $1, $3);
 		}
 	;
 
@@ -477,11 +477,11 @@ equality_expression
 	: relational_expression
 	| equality_expression EQ relational_expression
 		{
-			$$ = binary_expr (QC_EQ, $1, $3);
+			$$ = new_binary_expr (QC_EQ, $1, $3);
 		}
 	| relational_expression NE relational_expression
 		{
-			$$ = binary_expr (QC_NE, $1, $3);
+			$$ = new_binary_expr (QC_NE, $1, $3);
 		}
 	;
 
@@ -489,7 +489,7 @@ and_expression
 	: equality_expression
 	| and_expression '&' equality_expression
 		{
-			$$ = binary_expr ('&', $1, $3);
+			$$ = new_binary_expr ('&', $1, $3);
 		}
 	;
 
@@ -497,7 +497,7 @@ exclusive_or_expression
 	: and_expression
 	| exclusive_or_expression '^' and_expression
 		{
-			$$ = binary_expr ('^', $1, $3);
+			$$ = new_binary_expr ('^', $1, $3);
 		}
 	;
 
@@ -505,7 +505,7 @@ inclusive_or_expression
 	: exclusive_or_expression
 	| inclusive_or_expression '|' exclusive_or_expression
 		{
-			$$ = binary_expr ('|', $1, $3);
+			$$ = new_binary_expr ('|', $1, $3);
 		}
 	;
 
@@ -545,11 +545,12 @@ assignment_expression
 	: conditional_expression
 	| unary_expression assignment_operator assignment_expression
 		{
-			if ($2 == '=') {
-				$$ = assign_expr ($1, $3);
-			} else {
-				$$ = asx_expr ($2, $1, $3);
+			auto expr = $3;
+			if ($2 != '=') {
+				expr = paren_expr (expr);
+				expr = new_binary_expr ($2, $1, expr);
 			}
+			$$ = new_assign_expr ($1, expr);
 		}
 	;