From 7c0b011c0554710c0007ebdf6aca02202d09b09b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Wed, 24 Jul 2019 16:17:52 +0200
Subject: [PATCH] Fixed #9230 (Improve check: integer conversion overflow in
 return)

---
 lib/checktype.cpp | 84 +++++++++++++++++++++++++++--------------------
 lib/checktype.h   |  2 ++
 test/testtype.cpp |  5 +++
 3 files changed, 55 insertions(+), 36 deletions(-)

diff --git a/lib/checktype.cpp b/lib/checktype.cpp
index 1d35c56b8..e18aeceba 100644
--- a/lib/checktype.cpp
+++ b/lib/checktype.cpp
@@ -367,6 +367,7 @@ void CheckType::checkFloatToIntegerOverflow()
             vtint = tok->valueType();
             vtfloat = tok->astOperand1()->valueType();
             floatValues = &tok->astOperand1()->values();
+            checkFloatToIntegerOverflow(tok, vtint, vtfloat, floatValues);
         }
 
         // Assignment
@@ -374,49 +375,60 @@ void CheckType::checkFloatToIntegerOverflow()
             vtint = tok->astOperand1()->valueType();
             vtfloat = tok->astOperand2()->valueType();
             floatValues = &tok->astOperand2()->values();
+            checkFloatToIntegerOverflow(tok, vtint, vtfloat, floatValues);
         }
 
-        // TODO: function call
-
-        else
-            continue;
-
-        // Conversion of float to integer?
-        if (!vtint || !vtint->isIntegral())
-            continue;
-        if (!vtfloat || !vtfloat->isFloat())
-            continue;
-
-        for (const ValueFlow::Value &f : *floatValues) {
-            if (f.valueType != ValueFlow::Value::ValueType::FLOAT)
-                continue;
-            if (!mSettings->isEnabled(&f, false))
-                continue;
-            if (f.floatValue > ~0ULL)
-                floatToIntegerOverflowError(tok, f);
-            else if ((-f.floatValue) > (1ULL<<62))
-                floatToIntegerOverflowError(tok, f);
-            else if (mSettings->platformType != Settings::Unspecified) {
-                int bits = 0;
-                if (vtint->type == ValueType::Type::CHAR)
-                    bits = mSettings->char_bit;
-                else if (vtint->type == ValueType::Type::SHORT)
-                    bits = mSettings->short_bit;
-                else if (vtint->type == ValueType::Type::INT)
-                    bits = mSettings->int_bit;
-                else if (vtint->type == ValueType::Type::LONG)
-                    bits = mSettings->long_bit;
-                else if (vtint->type == ValueType::Type::LONGLONG)
-                    bits = mSettings->long_long_bit;
-                else
-                    continue;
-                if (bits < MathLib::bigint_bits && f.floatValue >= (((MathLib::biguint)1) << bits))
-                    floatToIntegerOverflowError(tok, f);
+        else if (tok->str() == "return" && tok->astOperand1() && tok->astOperand1()->valueType() && tok->astOperand1()->valueType()->isFloat()) {
+            const Scope *scope = tok->scope();
+            while (scope && scope->type != Scope::ScopeType::eLambda && scope->type != Scope::ScopeType::eFunction)
+                scope = scope->nestedIn;
+            if (scope && scope->type == Scope::ScopeType::eFunction && scope->function && scope->function->retDef) {
+                const ValueType &valueType = ValueType::parseDecl(scope->function->retDef, mSettings);
+                vtfloat = tok->astOperand1()->valueType();
+                floatValues = &tok->astOperand1()->values();
+                checkFloatToIntegerOverflow(tok, &valueType, vtfloat, floatValues);
             }
         }
     }
 }
 
+void CheckType::checkFloatToIntegerOverflow(const Token *tok, const ValueType *vtint, const ValueType *vtfloat, const std::list<ValueFlow::Value> *floatValues)
+{
+    // Conversion of float to integer?
+    if (!vtint || !vtint->isIntegral())
+        return;
+    if (!vtfloat || !vtfloat->isFloat())
+        return;
+
+    for (const ValueFlow::Value &f : *floatValues) {
+        if (f.valueType != ValueFlow::Value::ValueType::FLOAT)
+            continue;
+        if (!mSettings->isEnabled(&f, false))
+            continue;
+        if (f.floatValue > ~0ULL)
+            floatToIntegerOverflowError(tok, f);
+        else if ((-f.floatValue) > (1ULL<<62))
+            floatToIntegerOverflowError(tok, f);
+        else if (mSettings->platformType != Settings::Unspecified) {
+            int bits = 0;
+            if (vtint->type == ValueType::Type::CHAR)
+                bits = mSettings->char_bit;
+            else if (vtint->type == ValueType::Type::SHORT)
+                bits = mSettings->short_bit;
+            else if (vtint->type == ValueType::Type::INT)
+                bits = mSettings->int_bit;
+            else if (vtint->type == ValueType::Type::LONG)
+                bits = mSettings->long_bit;
+            else if (vtint->type == ValueType::Type::LONGLONG)
+                bits = mSettings->long_long_bit;
+            else
+                continue;
+            if (bits < MathLib::bigint_bits && f.floatValue >= (((MathLib::biguint)1) << bits))
+                floatToIntegerOverflowError(tok, f);
+        }
+    }
+}
+
 void CheckType::floatToIntegerOverflowError(const Token *tok, const ValueFlow::Value &value)
 {
     std::ostringstream errmsg;
diff --git a/lib/checktype.h b/lib/checktype.h
index b786287b8..8caa51679 100644
--- a/lib/checktype.h
+++ b/lib/checktype.h
@@ -73,6 +73,8 @@ public:
 
     /** @brief %Check for float to integer overflow */
     void checkFloatToIntegerOverflow();
+    void checkFloatToIntegerOverflow(const Token *tok, const ValueType *vtint, const ValueType *vtfloat, const std::list<ValueFlow::Value> *floatValues);
+
 private:
 
     // Error messages..
diff --git a/test/testtype.cpp b/test/testtype.cpp
index 7beef12ac..c6e120442 100644
--- a/test/testtype.cpp
+++ b/test/testtype.cpp
@@ -318,6 +318,11 @@ private:
               "  char c = 1234.5;\n"
               "}");
         ASSERT_EQUALS("[test.cpp:2]: (error) Undefined behaviour: float () to integer conversion overflow.\n", removeFloat(errout.str()));
+
+        check("char f(void) {\n"
+              "  return 1234.5;\n"
+              "}");
+        ASSERT_EQUALS("[test.cpp:2]: (error) Undefined behaviour: float () to integer conversion overflow.\n", removeFloat(errout.str()));
     }
 };