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Improved check: Complain if a variable is modified but not used again

This commit is contained in:
PKEuS 2016-10-10 21:27:40 +02:00
parent 04421f5601
commit 1227a3f596
3 changed files with 27 additions and 10 deletions
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11
lib/checkunusedvar.cpp
View File

@ -350,6 +350,8 @@ void Variables::modified(unsigned int varid, const Token* tok)
VariableUsage *usage = find(varid); VariableUsage *usage = find(varid);
if (usage) { if (usage) {
if (!usage->_var->isStatic())
usage->_read = false;
usage->_modified = true; usage->_modified = true;
usage->_lastAccess = tok; usage->_lastAccess = tok;
@ -1193,8 +1195,8 @@ void CheckUnusedVar::checkFunctionVariableUsage()
unassignedVariableError(usage._var->nameToken(), varname); unassignedVariableError(usage._var->nameToken(), varname);
// variable has been written but not read // variable has been written but not read
else if (!usage._read && !usage._modified) else if (!usage._read)
unreadVariableError(usage._lastAccess, varname); unreadVariableError(usage._lastAccess, varname, usage._modified);
// variable has been read but not written // variable has been read but not written
else if (!usage._write && !usage._allocateMemory && var && !var->isStlType() && !isEmptyType(var->type())) else if (!usage._write && !usage._allocateMemory && var && !var->isStlType() && !isEmptyType(var->type()))
@ -1213,8 +1215,11 @@ void CheckUnusedVar::allocatedButUnusedVariableError(const Token *tok, const std
reportError(tok, Severity::style, "unusedAllocatedMemory", "Variable '" + varname + "' is allocated memory that is never used.", CWE563, false); reportError(tok, Severity::style, "unusedAllocatedMemory", "Variable '" + varname + "' is allocated memory that is never used.", CWE563, false);
} }
void CheckUnusedVar::unreadVariableError(const Token *tok, const std::string &varname) void CheckUnusedVar::unreadVariableError(const Token *tok, const std::string &varname, bool modified)
{ {
if (modified)
reportError(tok, Severity::style, "unreadVariable", "Variable '" + varname + "' is modified but its new value is never used.", CWE563, false);
else
reportError(tok, Severity::style, "unreadVariable", "Variable '" + varname + "' is assigned a value that is never used.", CWE563, false); reportError(tok, Severity::style, "unreadVariable", "Variable '" + varname + "' is assigned a value that is never used.", CWE563, false);
} }

4
lib/checkunusedvar.h
View File

@ -78,7 +78,7 @@ private:
void unusedStructMemberError(const Token *tok, const std::string &structname, const std::string &varname, bool isUnion = false); void unusedStructMemberError(const Token *tok, const std::string &structname, const std::string &varname, bool isUnion = false);
void unusedVariableError(const Token *tok, const std::string &varname); void unusedVariableError(const Token *tok, const std::string &varname);
void allocatedButUnusedVariableError(const Token *tok, const std::string &varname); void allocatedButUnusedVariableError(const Token *tok, const std::string &varname);
void unreadVariableError(const Token *tok, const std::string &varname); void unreadVariableError(const Token *tok, const std::string &varname, bool modified);
void unassignedVariableError(const Token *tok, const std::string &varname); void unassignedVariableError(const Token *tok, const std::string &varname);
void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const { void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const {
@ -87,7 +87,7 @@ private:
// style/warning // style/warning
c.unusedVariableError(nullptr, "varname"); c.unusedVariableError(nullptr, "varname");
c.allocatedButUnusedVariableError(nullptr, "varname"); c.allocatedButUnusedVariableError(nullptr, "varname");
c.unreadVariableError(nullptr, "varname"); c.unreadVariableError(nullptr, "varname", false);
c.unassignedVariableError(nullptr, "varname"); c.unassignedVariableError(nullptr, "varname");
c.unusedStructMemberError(nullptr, "structname", "variable"); c.unusedStructMemberError(nullptr, "structname", "variable");
} }

20
test/testunusedvar.cpp
View File

@ -1130,7 +1130,8 @@ private:
" int &ii(i);\n" " int &ii(i);\n"
" ii--;\n" " ii--;\n"
"}"); "}");
ASSERT_EQUALS("[test.cpp:3]: (style) Variable 'i' is not assigned a value.\n", errout.str()); ASSERT_EQUALS("[test.cpp:3]: (style) Variable 'i' is not assigned a value.\n"
"[test.cpp:5]: (style) Variable 'ii' is modified but its new value is never used.\n", errout.str());
functionVariableUsage("void foo()\n" functionVariableUsage("void foo()\n"
"{\n" "{\n"
@ -1138,7 +1139,8 @@ private:
" int &ii=i;\n" " int &ii=i;\n"
" ii--;\n" " ii--;\n"
"}"); "}");
ASSERT_EQUALS("[test.cpp:3]: (style) Variable 'i' is not assigned a value.\n", errout.str()); ASSERT_EQUALS("[test.cpp:3]: (style) Variable 'i' is not assigned a value.\n"
"[test.cpp:5]: (style) Variable 'ii' is modified but its new value is never used.\n", errout.str());
} }
void localvar8() { void localvar8() {
@ -3409,6 +3411,16 @@ private:
" i += 5;\n" " i += 5;\n"
"}"); "}");
ASSERT_EQUALS("", errout.str()); ASSERT_EQUALS("", errout.str());
functionVariableUsage("void foo() {\n"
" static int x = 0;\n"
" print(x);\n"
" if(x > 5)\n"
" x = 0;\n"
" else\n"
" x++;\n"
"}");
ASSERT_EQUALS("", errout.str());
} }
void localvarextern() { void localvarextern() {
@ -3657,14 +3669,14 @@ private:
} }
void localvardynamic3() { void localvardynamic3() {
// Ticket #3477 - False positive that 'data' is not assigned a value // Ticket #3467 - False positive that 'data' is not assigned a value
functionVariableUsage("void foo() {\n" functionVariableUsage("void foo() {\n"
" int* data = new int[100];\n" " int* data = new int[100];\n"
" int* p = data;\n" " int* p = data;\n"
" for ( int i = 0; i < 10; ++i )\n" " for ( int i = 0; i < 10; ++i )\n"
" p++;\n" " p++;\n"
"}"); "}");
ASSERT_EQUALS("", errout.str()); ASSERT_EQUALS("[test.cpp:5]: (style) Variable 'p' is modified but its new value is never used.\n", errout.str());
} }
void localvararray1() { void localvararray1() {