clear errors on calling dead functions

4 files changed, 12 insertions, 5 deletions

diff --git a/src/compiler.js b/src/compiler.js
index 9c19aeb0..d74ff7cb 100644
--- a/src/compiler.js
+++ b/src/compiler.js
@@ -168,6 +168,8 @@ if (SAFE_HEAP >= 2) {
 EXPORTED_FUNCTIONS = set(EXPORTED_FUNCTIONS);
 EXPORTED_GLOBALS = set(EXPORTED_GLOBALS);
 EXCEPTION_CATCHING_WHITELIST = set(EXCEPTION_CATCHING_WHITELIST);
+
+if (DEAD_FUNCTIONS.length && ASSERTIONS) DEFAULT_LIBRARY_FUNCS_TO_INCLUDE.push('putchar'); // for debug output
 DEAD_FUNCTIONS = numberedSet(DEAD_FUNCTIONS);
 
 RUNTIME_DEBUG = LIBRARY_DEBUG || GL_DEBUG;
diff --git a/src/jsifier.js b/src/jsifier.js
index 9678a56d..6d8def39 100644
--- a/src/jsifier.js
+++ b/src/jsifier.js
@@ -1441,6 +1441,10 @@ function JSify(data, functionsOnly, givenFunctions) {
     if (callIdent in DEAD_FUNCTIONS) {
       var ret = 'abort(' + DEAD_FUNCTIONS[callIdent] + ')';
       if (ASM_JS) ret = asmCoercion(ret, returnType);
+      if (ASSERTIONS) {
+        assert(DEFAULT_LIBRARY_FUNCS_TO_INCLUDE.indexOf('putchar') >= 0, 'need putchar for DEAD_FUNCTIONS + ASSERTIONS output');
+        ret = '(' + makePrintChars('dead:' + callIdent, ',') + ',' + ret + ')';
+      }
       return ret;
     }
 
diff --git a/src/parseTools.js b/src/parseTools.js
index fe21dfd5..8347a929 100644
--- a/src/parseTools.js
+++ b/src/parseTools.js
@@ -2363,13 +2363,14 @@ function getTypeFromHeap(suffix) {
   }
 }
 
-// Generates code that prints without printf(), but just putchar (so can be directly inline)
-function makePrintChars(s) {
+// Generates code that prints without printf(), but just putchar (so can be directly inline in asm.js)
+function makePrintChars(s, sep) {
+  sep = sep || ';';
   var ret = '';
   for (var i = 0; i < s.length; i++) {
-    ret += '_putchar(' + s.charCodeAt(i) + ');';
+    ret += '_putchar(' + s.charCodeAt(i) + ')' + sep;
   }
-  ret += '_putchar(10);';
+  ret += '_putchar(10)';
   return ret;
 }
 
diff --git a/tests/runner.py b/tests/runner.py
index 33a2ef67..bd6fd838 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -8070,7 +8070,7 @@ def process(filename):
         Settings.DEAD_FUNCTIONS = []
 
         # Run the same code with argc that uses the dead function, see abort
-        test(('abort', 'is not a function'), args=['a', 'b'], no_build=True)
+        test(('dead:_unused' if Settings.ASSERTIONS else 'abort', 'is not a function'), args=['a', 'b'], no_build=True)
 
       # Normal stuff
       run_all('normal', r'''