From 023a3c037f102fcaa5e037b762c33d3537a67472 Mon Sep 17 00:00:00 2001
From: ISSOtm <eldredhabert0@gmail.com>
Date: Sun, 12 Apr 2020 22:52:32 +0200
Subject: [PATCH] Properly handle missing symbols

Fixes #512
---
 src/link/patch.c          | 6 +++++-
 test/link/sym-noexist.asm | 3 +++
 test/link/sym-noexist.out | 3 +++
 3 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 test/link/sym-noexist.asm
 create mode 100644 test/link/sym-noexist.out

diff --git a/src/link/patch.c b/src/link/patch.c
index d9f56cea..aeab74b2 100644
--- a/src/link/patch.c
+++ b/src/link/patch.c
@@ -337,7 +337,11 @@ static int32_t computeRPNExpr(struct Patch const *patch,
 
 			symbol = getSymbol(fileSymbols, value);
 
-			if (strcmp(symbol->name, "@")) {
+			if (!symbol) {
+				error("%s: Unknown symbol \"%s\"",
+				      patch->fileName,
+				      fileSymbols[value]->name);
+			} else if (strcmp(symbol->name, "@")) {
 				value = symbol->value;
 				/* Symbols attached to sections have offsets */
 				if (symbol->section)
diff --git a/test/link/sym-noexist.asm b/test/link/sym-noexist.asm
new file mode 100644
index 00000000..f6232128
--- /dev/null
+++ b/test/link/sym-noexist.asm
@@ -0,0 +1,3 @@
+SECTION "Test", ROM0
+	jp where
+	dw nothing
diff --git a/test/link/sym-noexist.out b/test/link/sym-noexist.out
new file mode 100644
index 00000000..035c6e3a
--- /dev/null
+++ b/test/link/sym-noexist.out
@@ -0,0 +1,3 @@
+error: sym-noexist.asm(3): Unknown symbol "nothing"
+error: sym-noexist.asm(2): Unknown symbol "where"
+Linking failed with 2 errors