From bf55e73560fae478c7440fab858c48884938b9fa Mon Sep 17 00:00:00 2001
From: Thomas Voss <mail@thomasvoss.com>
Date: Mon, 8 Jul 2024 21:13:59 +0200
Subject: Actually make unary plus an AST node

---
 src/analyzer.c | 20 ++++++++++----------
 src/codegen.c  |  2 ++
 src/parser.c   | 16 ++++++++++------
 src/parser.h   |  4 ++++
 4 files changed, 26 insertions(+), 16 deletions(-)

(limited to 'src')

diff --git a/src/analyzer.c b/src/analyzer.c
index b1c18e2..1bbb43c 100644
--- a/src/analyzer.c
+++ b/src/analyzer.c
@@ -21,15 +21,12 @@
 #include "types.h"
 
 #define LOG2_10       (3.321928)
-#define MP_BITCNT_MAX ((mp_bitcnt_t)-1)
-
-/* In debug builds we want to actually alloc a new mpq_t so that it’s
-   easier to free memory without doing a double free */
-#if DEBUG
-#	define MPQCPY(x, y) do { mpq_init(x); mpq_set(x, y); } while (false)
-#else
-#	define MPQCPY(x, y) (*(x) = *(y))
-#endif
+#define MP_BITCNT_MAX ((mp_bitcnt_t) - 1)
+#define MPQCPY(x, y)                                                           \
+	do {                                                                       \
+		mpq_init(x);                                                           \
+		mpq_set(x, y);                                                         \
+	} while (false)
 
 typedef struct {
 	scope_t *buf;
@@ -409,6 +406,7 @@ analyzeexpr(struct azctx *ctx, idx_t i)
 
 		err("analyzer: Unknown symbol ‘%.*s’", SV_PRI_ARGS(sv));
 	}
+	case ASTUNPLUS:
 	case ASTUNCMPL:
 	case ASTUNNEG: {
 		idx_t ni, rhs;
@@ -708,12 +706,14 @@ out:
 			err("analyzer: Cannot perform bitwise complement of constant");
 		break;
 	}
+	case ASTUNPLUS:
 	case ASTUNNEG: {
 		idx_t rhs = ctx->ast.kids[i].rhs;
 		ni = constfoldexpr(ctx, ctx->types[i], rhs);
 		if (TESTBIT(ctx->cnst, rhs)) {
 			MPQCPY(ctx->folds[i].q, ctx->folds[rhs].q);
-			mpq_neg(ctx->folds[i].q, ctx->folds[i].q);
+			if (ctx->ast.kinds[i] == ASTUNNEG)
+				mpq_neg(ctx->folds[i].q, ctx->folds[i].q);
 		}
 		break;
 	}
diff --git a/src/codegen.c b/src/codegen.c
index 27f5277..35e19f9 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -211,6 +211,8 @@ codegentypedexpr(struct cgctx ctx, idx_t i, type_t *T, LLVMValueRef *outv)
 		*outv = LLVMBuildLoad2(ctx.bob, t, ptrval, "load");
 		return fwdnode(ctx.ast, i);
 	}
+	case ASTUNPLUS:
+		return codegentypedexpr(ctx, ctx.ast.kids[i].rhs, T, outv);
 	case ASTUNCMPL: {
 		LLVMValueRef v, minus_one;
 		minus_one = LLVMConstInt(type2llvm(ctx, ctx.types[i]), -1, false);
diff --git a/src/parser.c b/src/parser.c
index 0a5f632..e602271 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -83,6 +83,7 @@ fwdnode(ast_t ast, idx_t i)
 		case ASTFN:
 		case ASTUNCMPL:
 		case ASTUNNEG:
+		case ASTUNPLUS:
 			i = ast.kids[i].rhs;
 			break;
 		case ASTCALLSTMT:
@@ -259,12 +260,6 @@ parseexpratom(ast_t *ast, lexemes_t toks)
 
 	idx_t i = astalloc(ast);
 
-	/* Unary plus is kind of a fake syntactic construct.  We just pretend
-	   like it doesn’t exist, but allow it in the syntax to be consistent
-	   with unary negation. */
-	while (toks.kinds[toksidx] == LEXPLUS)
-		toksidx++;
-
 	ast->lexemes[i] = toksidx;
 
 	switch (toks.kinds[toksidx++]) {
@@ -274,6 +269,15 @@ parseexpratom(ast_t *ast, lexemes_t toks)
 	case LEXIDENT:
 		ast->kinds[i] = ASTIDENT;
 		break;
+	case LEXPLUS:
+		/* Unary plus is kind of a fake syntactic construct.  We would
+		   ideally just pretend like it doesn’t exist, but allow it in
+		   the syntax to be consistent with unary negation.  We can’t
+		   just ignoring it in parsing though, because we need to
+		   disallow the statements ‘x := 0; +x = 1;’ */
+		ast->kinds[i] = ASTUNPLUS;
+		ast->kids[i].rhs = parseexpratom(ast, toks);
+		break;
 	case LEXMINUS:
 		ast->kinds[i] = ASTUNNEG;
 		ast->kids[i].rhs = parseexpratom(ast, toks);
diff --git a/src/parser.h b/src/parser.h
index 5d5c53b..14ab4b8 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -53,6 +53,10 @@ enum {
 	   ‘lhs = rhs’ */
 	ASTASIGN,
 
+	/* Unary plus
+	   ‘+rhs’ */
+	ASTUNPLUS,
+
 	/* Unary negation
 	   ‘-rhs’ */
 	ASTUNNEG,
-- 
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