Backport of 6e98a8184b52173cf961cc4052bdd81c33b04244 to gawk-5.1-stable

Fix-memory-leak-when-a-b-appears-in-expressions.patch

From e8195a4628f94592a6c9e64672c5f42648a7f090 Mon Sep 17 00:00:00 2001
Date: Mon, 27 Feb 2023 21:32:29 +0200
Subject: [PATCH] Fix memory leak when $a = $b appears in expressions.

(cherry picked from commit 6e98a8184b52173cf961cc4052bdd81c33b04244)
---
 awk.h       |  1 +
 awkgram.c   | 29 ++++++++++-------------------
 awkgram.y   | 29 ++++++++++-------------------
 eval.c      |  1 +
 interpret.h |  5 +++++
 profile.c   | 19 ++++++++++++++++---
 6 files changed, 43 insertions(+), 41 deletions(-)

diff --git a/awk.h b/awk.h
index ca648087..186e58ff 100644
--- a/awk.h
+++ b/awk.h
@@ -625,6 +625,7 @@ typedef enum opcodeval {
 	Op_store_var,		/* simple variable assignment optimization */
 	Op_store_sub,		/* array[subscript] assignment optimization */
 	Op_store_field,  	/* $n assignment optimization */
+	Op_store_field_exp,  	/* $n assignment optimization in an expression */
 	Op_assign_times,
 	Op_assign_quotient,
 	Op_assign_mod,
diff --git a/awkgram.c b/awkgram.c
index 117f338f..8483189f 100644
--- a/awkgram.c
+++ b/awkgram.c
@@ -8369,7 +8369,8 @@ mk_assignment(INSTRUCTION *lhs, INSTRUCTION *rhs, INSTRUCTION *op)
 	else
 		ip = lhs;
 
-	(void) list_append(ip, op);
+	if (tp->opcode != Op_field_spec_lhs || op->opcode != Op_assign)
+		(void) list_append(ip, op);
 
 	if (tp->opcode == Op_push_lhs
 			&& tp->memory->type == Node_var
@@ -8381,9 +8382,14 @@ mk_assignment(INSTRUCTION *lhs, INSTRUCTION *rhs, INSTRUCTION *op)
 		(void) list_append(ip, instruction(Op_var_assign));
 		ip->lasti->assign_var = tp->memory->var_assign;
 	} else if (tp->opcode == Op_field_spec_lhs) {
-		(void) list_append(ip, instruction(Op_field_assign));
-		ip->lasti->field_assign = (Func_ptr) 0;
-		tp->target_assign = ip->lasti;
+		if (op->opcode == Op_assign) {
+			bcfree(op);
+			tp->opcode = Op_store_field_exp;
+		} else {
+			(void) list_append(ip, instruction(Op_field_assign));
+			ip->lasti->field_assign = (Func_ptr) 0;
+			tp->target_assign = ip->lasti;
+		}
 	} else if (tp->opcode == Op_subscript_lhs) {
 		(void) list_append(ip, instruction(Op_subscript_assign));
 	}
@@ -8476,21 +8482,6 @@ optimize_assignment(INSTRUCTION *exp)
 			}
 			break;
 
-		case Op_field_spec_lhs:
-			if (i2->nexti->opcode == Op_assign
-					&& i2->nexti->nexti == i1
-					&& i1->opcode == Op_field_assign
-			) {
-				/* $n = .. */
-				i2->opcode = Op_store_field;
-				bcfree(i2->nexti);  /* Op_assign */
-				i2->nexti = NULL;
-				bcfree(i1);          /* Op_field_assign */
-				exp->lasti = i2;    /* update Op_list */
-				return exp;
-			}
-			break;
-
 		case Op_push_array:
 			if (i2->nexti->nexti->opcode == Op_subscript_lhs) {
 				i3 = i2->nexti->nexti;
diff --git a/awkgram.y b/awkgram.y
index d9dbaa71..a8aee3e1 100644
--- a/awkgram.y
+++ b/awkgram.y
@@ -5861,7 +5861,8 @@ mk_assignment(INSTRUCTION *lhs, INSTRUCTION *rhs, INSTRUCTION *op)
 	else
 		ip = lhs;
 
-	(void) list_append(ip, op);
+	if (tp->opcode != Op_field_spec_lhs || op->opcode != Op_assign)
+		(void) list_append(ip, op);
 
 	if (tp->opcode == Op_push_lhs
 			&& tp->memory->type == Node_var
@@ -5873,9 +5874,14 @@ mk_assignment(INSTRUCTION *lhs, INSTRUCTION *rhs, INSTRUCTION *op)
 		(void) list_append(ip, instruction(Op_var_assign));
 		ip->lasti->assign_var = tp->memory->var_assign;
 	} else if (tp->opcode == Op_field_spec_lhs) {
-		(void) list_append(ip, instruction(Op_field_assign));
-		ip->lasti->field_assign = (Func_ptr) 0;
-		tp->target_assign = ip->lasti;
+		if (op->opcode == Op_assign) {
+			bcfree(op);
+			tp->opcode = Op_store_field_exp;
+		} else {
+			(void) list_append(ip, instruction(Op_field_assign));
+			ip->lasti->field_assign = (Func_ptr) 0;
+			tp->target_assign = ip->lasti;
+		}
 	} else if (tp->opcode == Op_subscript_lhs) {
 		(void) list_append(ip, instruction(Op_subscript_assign));
 	}
@@ -5968,21 +5974,6 @@ optimize_assignment(INSTRUCTION *exp)
 			}
 			break;
 
-		case Op_field_spec_lhs:
-			if (i2->nexti->opcode == Op_assign
-					&& i2->nexti->nexti == i1
-					&& i1->opcode == Op_field_assign
-			) {
-				/* $n = .. */
-				i2->opcode = Op_store_field;
-				bcfree(i2->nexti);  /* Op_assign */
-				i2->nexti = NULL;
-				bcfree(i1);          /* Op_field_assign */
-				exp->lasti = i2;    /* update Op_list */
-				return exp;
-			}
-			break;
-
 		case Op_push_array:
 			if (i2->nexti->nexti->opcode == Op_subscript_lhs) {
 				i3 = i2->nexti->nexti;
diff --git a/eval.c b/eval.c
index 013ee062..3807a0aa 100644
--- a/eval.c
+++ b/eval.c
@@ -295,6 +295,7 @@ static struct optypetab {
 	{ "Op_store_var", " = " },
 	{ "Op_store_sub", " = " },
 	{ "Op_store_field", " = " },
+	{ "Op_store_field_exp", " = " },
 	{ "Op_assign_times", " *= " },
 	{ "Op_assign_quotient", " /= " },
 	{ "Op_assign_mod", " %= " },
diff --git a/interpret.h b/interpret.h
index bda9a01e..444a1122 100644
--- a/interpret.h
+++ b/interpret.h
@@ -761,6 +761,7 @@ mod:
 			break;
 
 		case Op_store_field:
+		case Op_store_field_exp:
 		{
 			/* field assignment optimization,
 			 * see awkgram.y (optimize_assignment)
@@ -783,6 +784,10 @@ mod:
 			UNFIELD(*lhs, r);
 			/* field variables need the string representation: */
 			force_string(*lhs);
+			if (op == Op_store_field_exp) {
+				UPREF(*lhs);
+				PUSH(*lhs);
+			}
 		}
 			break;
 
diff --git a/profile.c b/profile.c
index 13e13e6f..3b50ae26 100644
--- a/profile.c
+++ b/profile.c
@@ -544,15 +544,28 @@ cleanup:
 			break;
 
 		case Op_store_field:
+		case Op_store_field_exp:
+		{
+			char *assignment, *final;
+
 			t1 = pp_pop(); /* field num */
 			if (is_binary(t1->type))
 				pp_parenthesize(t1);
 			t2 = pp_pop(); /* r.h.s. */
-			fprintf(prof_fp, "$%s%s%s", t1->pp_str, op2str(pc->opcode), t2->pp_str);
+			assignment = pp_group3(t1->pp_str, op2str(pc->opcode), t2->pp_str);
+			final = pp_group3("$", assignment, "");
+			efree(assignment);
 			pp_free(t2);
 			pp_free(t1);
-			if ((flags & IN_FOR_HEADER) == 0)
-				pc = end_line(pc);
+			if (pc->opcode == Op_store_field_exp)
+				pp_push(pc->opcode, final, CAN_FREE, NULL);
+			else {
+				fprintf(prof_fp, "%s", final);
+				efree(final);
+				if ((flags & IN_FOR_HEADER) == 0)
+					pc = end_line(pc);
+			}
+		}
 			break;
 
 		case Op_concat:
-- 
2.39.2