From 79af6f65d7bbf961572a33933b18b11c4b0d5228 Mon Sep 17 00:00:00 2001
From: Ahti Legonkov <ahti.legonkov@gmail.com>
Date: Sun, 22 Apr 2012 06:49:42 +0200
Subject: [PATCH] Fixed #3699 (cppcheck hangs with 100% cpu load on parsing
 preprocessor code)

---
 lib/preprocessor.cpp      | 14 +++++++++++---
 test/testpreprocessor.cpp | 19 +++++++++++++++++++
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/lib/preprocessor.cpp b/lib/preprocessor.cpp
index 05fc23089..303c8915e 100644
--- a/lib/preprocessor.cpp
+++ b/lib/preprocessor.cpp
@@ -890,10 +890,18 @@ static void simplifyVarMap(std::map<std::string, std::string> &variables)
         // TODO: 1. tokenize the value, replace each token like this.
         // TODO: 2. handle function-macros too.
 
+        std::set<std::string> seenVariables;
         std::map<std::string, std::string>::iterator it = variables.find(varValue);
-        while (it != variables.end() && it->first != it->second && it != i) {
-            varValue = it->second;
-            it = variables.find(varValue);
+        while (it != variables.end() && it->first != it->second) {
+            if (seenVariables.find(it->first) != seenVariables.end()) {
+                // We have already seen this variable. there is a cycle of #define that we can't process at
+                // this time. Stop trying to simplify the current variable and leave it as is.
+                break;
+            } else {
+                seenVariables.insert(it->first);
+                varValue = it->second;
+                it = variables.find(varValue);
+            }
         }
     }
 }
diff --git a/test/testpreprocessor.cpp b/test/testpreprocessor.cpp
index cddf6e19e..0c2363198 100644
--- a/test/testpreprocessor.cpp
+++ b/test/testpreprocessor.cpp
@@ -132,6 +132,7 @@ private:
 
         TEST_CASE(if_macro_eq_macro); // #3536
         TEST_CASE(ticket_3675);
+        TEST_CASE(ticket_3699);
 
         TEST_CASE(multiline1);
         TEST_CASE(multiline2);
@@ -1550,6 +1551,24 @@ private:
         // There's nothing to assert. It just needs to not hang.
     }
 
+    void ticket_3699() {
+        const std::string code("#define INLINE __forceinline\n"
+                               "#define inline __forceinline\n"
+                               "#define __forceinline inline\n"
+                               "#if !defined(_WIN32)\n"
+                               "#endif\n"
+                               "INLINE inline __forceinline\n"
+                              );
+        Settings settings;
+        Preprocessor preprocessor(&settings, this);
+        std::istringstream istr(code);
+        std::map<std::string, std::string> actual;
+        preprocessor.preprocess(istr, actual, "file.c");
+
+        // First, it must not hang. Second, inline must becomes inline, and __forceinline must become __forceinline.
+        ASSERT_EQUALS("\n\n\n\n\n$$$__forceinline $$inline $$__forceinline\n", actual[""]);
+    }
+
     void multiline1() {
         const char filedata[] = "#define str \"abc\"     \\\n"
                                 "            \"def\"       \n"