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Fix issue 9235: new crash in astutils isVariableChanged from endless recursion #2040

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Merged
danmar merged 1 commit into from
Jul 26, 2019
Merged

Fix issue 9235: new crash in astutils isVariableChanged from endless recursion #2040

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12 changes: 7 additions & 5 deletions lib/astutils.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -968,10 +968,12 @@ bool isVariableChangedByFunctionCall(const Token *tok, const Settings *settings,
return arg && !arg->isConst() && arg->isReference();
}

bool isVariableChanged(const Token *start, const Token *end, const nonneg int varid, bool globalvar, const Settings *settings, bool cpp)
bool isVariableChanged(const Token *start, const Token *end, const nonneg int varid, bool globalvar, const Settings *settings, bool cpp, int depth)
{
if (!precedes(start, end))
return false;
if (depth < 0)
return true;
for (const Token *tok = start; tok != end; tok = tok->next()) {
if (tok->varId() != varid) {
if (globalvar && Token::Match(tok, "%name% ("))
Expand All @@ -994,7 +996,7 @@ bool isVariableChanged(const Token *start, const Token *end, const nonneg int va
// Check if assigning to a non-const lvalue
const Variable * var = getLHSVariable(tok2->astParent());
if (var && var->isReference() && !var->isConst() && var->nameToken() && var->nameToken()->next() == tok2->astParent()) {
if (!var->isLocal() || isVariableChanged(var, settings, cpp))
if (!var->isLocal() || isVariableChanged(var, settings, cpp, depth - 1))
return true;
}
}
Expand Down Expand Up @@ -1050,15 +1052,15 @@ bool isVariableChanged(const Token *start, const Token *end, const nonneg int va
const Variable * loopVar = varTok->variable();
if (!loopVar)
continue;
if (!loopVar->isConst() && loopVar->isReference() && isVariableChanged(loopVar, settings, cpp))
if (!loopVar->isConst() && loopVar->isReference() && isVariableChanged(loopVar, settings, cpp, depth - 1))
return true;
continue;
}
}
return false;
}

bool isVariableChanged(const Variable * var, const Settings *settings, bool cpp)
bool isVariableChanged(const Variable * var, const Settings *settings, bool cpp, int depth)
{
if (!var)
return false;
Expand All @@ -1069,7 +1071,7 @@ bool isVariableChanged(const Variable * var, const Settings *settings, bool cpp)
return false;
if (Token::Match(start, "; %varid% =", var->declarationId()))
start = start->tokAt(2);
return isVariableChanged(start->next(), var->scope()->bodyEnd, var->declarationId(), var->isGlobal(), settings, cpp);
return isVariableChanged(start->next(), var->scope()->bodyEnd, var->declarationId(), var->isGlobal(), settings, cpp, depth);
}

int numberOfArguments(const Token *start)
Expand Down
4 changes: 2 additions & 2 deletions lib/astutils.h
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Original file line number Diff line number Diff line change
Expand Up @@ -133,9 +133,9 @@ bool isVariableChangedByFunctionCall(const Token *tok, nonneg int varid, const S
bool isVariableChangedByFunctionCall(const Token *tok, const Settings *settings, bool *inconclusive);

/** Is variable changed in block of code? */
bool isVariableChanged(const Token *start, const Token *end, const nonneg int varid, bool globalvar, const Settings *settings, bool cpp);
bool isVariableChanged(const Token *start, const Token *end, const nonneg int varid, bool globalvar, const Settings *settings, bool cpp, int depth = 20);

bool isVariableChanged(const Variable * var, const Settings *settings, bool cpp);
bool isVariableChanged(const Variable * var, const Settings *settings, bool cpp, int depth = 20);

bool isAliased(const Variable *var);

Expand Down
4 changes: 4 additions & 0 deletions test/testastutils.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -147,6 +147,10 @@ class TestAstUtils : public TestFixture {
" int b;\n"
" if (b) { (int)((INTOF(8))result >> b); }\n"
"}", "if", "}");
// #9235
ASSERT_EQUALS(true, isVariableChanged("void f() {\n"
" int &a = a;\n"
"}\n", "= a", "}"));
}

bool isVariableChangedByFunctionCall(const char code[], const char pattern[], bool *inconclusive) {
Expand Down