Fix 12033: false negative: uninitialized data passed as const data to function (#5747)

Author: pfultz2

lib/astutils.cpp

@@ -2651,8 +2651,11 @@ bool isVariableChanged(const Token *tok, int indirect, const Settings *settings,
         const Token * ptok = tok2;
         while (Token::Match(ptok->astParent(), ".|::|["))
             ptok = ptok->astParent();
+        int pindirect = indirect;
+        if (indirect == 0 && astIsLHS(tok2) && Token::Match(ptok, ". %var%") && astIsPointer(ptok->next()))
+            pindirect = 1;
         bool inconclusive = false;
-        bool isChanged = isVariableChangedByFunctionCall(ptok, indirect, settings, &inconclusive);
+        bool isChanged = isVariableChangedByFunctionCall(ptok, pindirect, settings, &inconclusive);
         isChanged |= inconclusive;
         if (isChanged)
             return true;
@@ -3257,6 +3260,8 @@ static ExprUsage getFunctionUsage(const Token* tok, int indirect, const Settings
                 continue;
             if (arg->isReference())
                 return ExprUsage::PassedByReference;
+            if (arg->isPointer() && indirect == 1)
+                return ExprUsage::PassedByReference;
         }
         if (!args.empty() && indirect == 0 && !addressOf)
             return ExprUsage::Used;
@@ -3301,6 +3306,8 @@ ExprUsage getExprUsage(const Token* tok, int indirect, const Settings* settings,
             parent = parent->astParent();
         if (Token::Match(parent, "%assign%") && (astIsRHS(tok) || astIsLHS(parent->astOperand1())))
             return ExprUsage::NotUsed;
+        if (Token::Match(parent, "++|--"))
+            return ExprUsage::NotUsed;
         if (parent->isConstOp())
             return ExprUsage::NotUsed;
         if (parent->isCast())

lib/checkuninitvar.cpp

@@ -1642,12 +1642,7 @@ void CheckUninitVar::valueFlowUninit()
                     const bool isarray = tok->variable()->isArray();
                     if (isarray && tok->variable()->isMember())
                         continue; // Todo: this is a bailout
-                    const bool ispointer = astIsPointer(tok) && !isarray;
                     const bool deref = CheckNullPointer::isPointerDeRef(tok, unknown, mSettings);
-                    if (ispointer && v->indirect == 1 && !deref)
-                        continue;
-                    if (isarray && !deref)
-                        continue;
                     uninitderef = deref && v->indirect == 0;
                     const bool isleaf = isLeafDot(tok) || uninitderef;
                     if (!isleaf && Token::Match(tok->astParent(), ". %name%") && (tok->astParent()->next()->varId() || tok->astParent()->next()->isEnumerator()))

test/testuninitvar.cpp

@@ -6313,7 +6313,7 @@ class TestUninitVar : public TestFixture {
                         "    f(a, b);\n"
                         "    printf(\"%s\", a);\n"
                         "}");
-        ASSERT_EQUALS("[test.cpp:5]: (error) Uninitialized variable: a\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: a\n", errout.str());
 
         valueFlowUninit("void usage(const char *);\n" // #10330
                         "int main(int argc, char* argv[]) {\n"
@@ -6334,6 +6334,14 @@ class TestUninitVar : public TestFixture {
                         "    if (pwd == NULL) {}\n"
                         "}");
         ASSERT_EQUALS("[test.cpp:15] -> [test.cpp:17]: (warning) Uninitialized variable: pwd\n", errout.str());
+
+        // #12033
+        valueFlowUninit("void g(const char*p);\n"
+                        "void f() {\n"
+                        "    char buf[10];\n"
+                        "    g(buf);\n"
+                        "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: buf\n", errout.str());
     }
 
     void valueFlowUninitBreak() { // Do not show duplicate warnings about the same uninitialized value
@@ -6385,7 +6393,7 @@ class TestUninitVar : public TestFixture {
                         "    someType_t gVar;\n"
                         "    bar(&gVar);\n"
                         "}");
-        ASSERT_EQUALS("[test.cpp:9] -> [test.cpp:5]: (warning) Uninitialized variable: p->flags\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:9]: (error) Uninitialized variable: &gVar\n", errout.str());
 
         valueFlowUninit("typedef struct\n"
                         "{\n"
@@ -6917,7 +6925,7 @@ class TestUninitVar : public TestFixture {
                         "  foo(123, &abc);\n"
                         "  return abc.b;\n"
                         "}");
-        ASSERT_EQUALS("[test.cpp:6]: (error) Uninitialized variable: abc.b\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:5]: (error) Uninitialized variable: &abc\n", errout.str());
 
         valueFlowUninit("struct ABC { int a; int b; int c; };\n"
                         "void foo() {\n"