From 809c70b9c3e0bbdaa05bf2a823f5677a1bb78356 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Fri, 14 May 2021 21:36:51 +0200
Subject: [PATCH] uninitialized variables; fix FP in for loop

---
 lib/checkuninitvar.cpp | 20 ++++++++++++++++++++
 test/testuninitvar.cpp | 19 +++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/lib/checkuninitvar.cpp b/lib/checkuninitvar.cpp
index 522d40017..f61039ce9 100644
--- a/lib/checkuninitvar.cpp
+++ b/lib/checkuninitvar.cpp
@@ -836,6 +836,26 @@ const Token* CheckUninitVar::checkLoopBodyRecursive(const Token *start, const Va
             return nullptr;
         }
 
+        // for loop; skip third expression until loop body has been analyzed..
+        if (tok->str() == ";" && Token::simpleMatch(tok->astParent(), ";") && Token::simpleMatch(tok->astParent()->astParent(), "(")) {
+            const Token *top = tok->astParent()->astParent();
+            if (!Token::simpleMatch(top->previous(), "for (") || !Token::simpleMatch(top->link(), ") {"))
+                continue;
+            const Token *bodyStart = top->link()->next();
+            const Token *errorToken = checkLoopBodyRecursive(bodyStart, var, alloc, membervar, bailout);
+            if (errorToken)
+                return errorToken;
+            if (bailout)
+                return nullptr;
+        }
+        // for loop; skip loop body if there is third expression
+        if (Token::simpleMatch(tok, ") {") &&
+            Token::simpleMatch(tok->link()->previous(), "for (") &&
+            Token::simpleMatch(tok->link()->astOperand2(), ";")  &&
+            Token::simpleMatch(tok->link()->astOperand2()->astOperand2(), ";")) {
+            tok = tok->linkAt(1);
+        }
+
         if (tok->str() == "{") {
             const Token *errorToken1 = checkLoopBodyRecursive(tok, var, alloc, membervar, bailout);
             if (Token::simpleMatch(tok->link(), "} else {")) {
diff --git a/test/testuninitvar.cpp b/test/testuninitvar.cpp
index 3e7d99b16..66d1fda6f 100644
--- a/test/testuninitvar.cpp
+++ b/test/testuninitvar.cpp
@@ -1283,6 +1283,25 @@ private:
                        "    }\n"
                        "}");
         ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: learn\n", errout.str());
+
+        checkUninitVar("void foo() {\n"
+                       "  Entry *entry, *nextEntry;\n"
+                       "  for(int i = 0; i < 10; i++) {\n"
+                       "    for(entry = buckets[i]; entry != NULL; entry = nextEntry) {\n" // <- nextEntry is not uninitialized
+                       "      nextEntry = entry->next;\n"
+                       "    }\n"
+                       "  }\n"
+                       "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        checkUninitVar("void foo() {\n"
+                       "  Entry *entry, *nextEntry;\n"
+                       "  for(int i = 0; i < 10; i++) {\n"
+                       "    for(entry = buckets[i]; entry != NULL; entry = nextEntry) {\n"
+                       "    }\n"
+                       "  }\n"
+                       "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: nextEntry\n", errout.str());
     }
 
     // switch..