C++ Valgrind: Conditional jump or move depends on uninitialised value(s) - c++

Question

So I'm implementing a weighted digraph with templates using a dynamic matrix (which I also implemented).
The thing is, when I use my Matrix class on its own it works fine, but inside the Graph class it just doesn't and I don't understand why. I was hoping someone could help me out.
Here is the Matrix class. I tested it directly on main.cpp with Valgrind and it didn't show anything.
template <typename Type>
class Matrix {
private:
Type** matrix;
unsigned size;
Type null;
public:
Matrix();
Matrix(unsigned size, Type null);
Matrix(const Matrix& matrix);
~Matrix();
Type getData(unsigned row, unsigned col);
void insert(Type data, unsigned row, unsigned col);
void freeMatrixResources(Type** matrix);
void resize(unsigned size);
void assignNull(unsigned int beginRow, unsigned int endRow, unsigned int beginCol, unsigned int endCol);
void copyData(Type** matrix, unsigned begin, unsigned end);
void printMatrix();
Type operator()(unsigned int row, unsigned int col);
friend ostream& operator << (ostream& o, const Matrix<Type> &m);
};
template <typename Type>
ostream& operator << (ostream& out, const Matrix<Type> &m) {
for (int i = 0; i < m.size; ++i) {
out << "\t\t";
for (int j = 0; j < m.size; ++j) {
out << m.getData(i, j) << "\t";
}
out << "\n";
}
out << "\n";
return out;
}
template <typename Type>
Type Matrix<Type>:: operator()(unsigned int row, unsigned int col) {
return matrix[row][col];
}
template <typename Type>
Matrix<Type>:: Matrix() {
matrix = 0;
size = 0;
null = 0;
}
template <typename Type>
Matrix<Type>:: Matrix(unsigned size, Type null) {
matrix = new Type*[size];
for (int i = 0; i < size; ++i)
matrix[i] = new Type[size];
this->size = size;
this->null = null;
assignNull(0, size, 0, size);
}
template <typename Type>
Matrix<Type>:: Matrix(const Matrix<Type> &matrix) {
this->matrix = new Type*[matrix.size];
for (int i = 0; i < matrix.size; ++i)
matrix[i] = new Type[matrix.size];
copyData(matrix,0,0);
}
template <typename Type>
Matrix<Type>:: ~Matrix() {
freeMatrixResources(matrix);
}
template <typename Type>
Type Matrix<Type>:: getData(unsigned row, unsigned col) {
return matrix[row][col];
}
template <typename Type>
void Matrix<Type>:: insert(Type data, unsigned int row, unsigned int col) {
matrix[row][col] = data;
}
template <typename Type>
void Matrix<Type>:: freeMatrixResources(Type** matrix) {
for (int i = 0; i < size; ++i) {
delete [] matrix[i];
}
delete [] matrix;
}
template <typename Type>
void Matrix<Type>:: resize(unsigned int newSize) {
if (this->size != newSize) {
Type** aux = matrix;
matrix = new Type*[newSize];
for (int i = 0; i < newSize; ++i)
matrix[i] = new Type[newSize];
if (this->size < newSize) {
copyData(aux, 0, this->size);
assignNull(this->size, newSize, 0, newSize);
assignNull(0, newSize, this->size, newSize);
}
else
copyData(aux, 0, newSize);
freeMatrixResources(aux);
this->size = newSize;
}
}
template <typename Type>
void Matrix<Type>:: assignNull(unsigned int beginRow, unsigned int endRow, unsigned int beginCol, unsigned int endCol) {
for (int i = beginRow; i < endRow; ++i) {
for (int j = beginCol; j < endCol; ++j) {
matrix[i][j] = null;
}
}
}
template <typename Type>
void Matrix<Type>:: copyData(Type** matrix, unsigned int begin, unsigned int end) {
for (int i = begin; i < end; ++i) {
for (int j = begin; j < end; ++j) {
this->matrix[i][j] = matrix[i][j];
}
}
}
template <typename Type>
void Matrix<Type>:: printMatrix() {
for (int i = 0; i < size; ++i) {
cout << "\t\t";
for (int j = 0; j < size; ++j) {
cout << matrix[i][j] << "\t";
}
cout << "\n";
}
cout << "\n";
}
But then, when I run the Graph program with valgrind --tool=memcheck --leak-check=full "./cmake-build-debug/graphTemplates" the output says Uninitialised value was created by a stack allocation, Conditional jump or move depends on uninitialised value(s)
==155342== Memcheck, a memory error detector
==155342== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==155342== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==155342== Command: ./cmake-build-debug/graphTemplates
==155342==
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x109BEC: Matrix<int>::resize(unsigned int) (Matrix.h:100)
==155342== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155342== by 0x109327: main (main.cpp:36)
==155342==
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x109C0D: Matrix<int>::resize(unsigned int) (Matrix.h:103)
==155342== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155342== by 0x109327: main (main.cpp:36)
==155342==
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x483C530: operator new[](unsigned long) (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==155342== by 0x109C1A: Matrix<int>::resize(unsigned int) (Matrix.h:103)
==155342== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155342== by 0x109327: main (main.cpp:36)
==155342==
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x109C39: Matrix<int>::resize(unsigned int) (Matrix.h:104)
==155342== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155342== by 0x109327: main (main.cpp:36)
==155342==
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x109C4B: Matrix<int>::resize(unsigned int) (Matrix.h:105)
==155342== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155342== by 0x109327: main (main.cpp:36)
==155342==
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x483C530: operator new[](unsigned long) (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==155342== by 0x109C74: Matrix<int>::resize(unsigned int) (Matrix.h:105)
==155342== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155342== by 0x109327: main (main.cpp:36)
==155342==
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x109C88: Matrix<int>::resize(unsigned int) (Matrix.h:107)
==155342== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155342== by 0x109327: main (main.cpp:36)
==155342==
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x109D51: Matrix<int>::assignNull(unsigned int, unsigned int, unsigned int, unsigned int) (Matrix.h:122)
==155342== by 0x109CC8: Matrix<int>::resize(unsigned int) (Matrix.h:109)
==155342== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155342== by 0x109327: main (main.cpp:36)
==155342==
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x109D5F: Matrix<int>::assignNull(unsigned int, unsigned int, unsigned int, unsigned int) (Matrix.h:123)
==155342== by 0x109CC8: Matrix<int>::resize(unsigned int) (Matrix.h:109)
==155342== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155342== by 0x109327: main (main.cpp:36)
==155342==
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x109D51: Matrix<int>::assignNull(unsigned int, unsigned int, unsigned int, unsigned int) (Matrix.h:122)
==155342== by 0x109CE9: Matrix<int>::resize(unsigned int) (Matrix.h:110)
==155342== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155342== by 0x109327: main (main.cpp:36)
==155342==
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x109D5F: Matrix<int>::assignNull(unsigned int, unsigned int, unsigned int, unsigned int) (Matrix.h:123)
==155342== by 0x109CE9: Matrix<int>::resize(unsigned int) (Matrix.h:110)
==155342== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155342== by 0x109327: main (main.cpp:36)
==155342==
==155342== Use of uninitialised value of size 8
==155342== at 0x109A5E: Matrix<int>::insert(int, unsigned int, unsigned int) (Matrix.h:87)
==155342== by 0x109794: Graph<int, int>::addEdge(int, int, int) (Graph.h:121)
==155342== by 0x109327: main (main.cpp:36)
==155342==
Edge connecting 3 and 1 with cost 7 added successfully!
==155342== Conditional jump or move depends on uninitialised value(s)
==155342== at 0x109EB3: Matrix<int>::freeMatrixResources(int**) (Matrix.h:92)
==155342== by 0x109A99: Matrix<int>::~Matrix() (Matrix.h:77)
==155342== by 0x10958E: Graph<int, int>::~Graph() (Graph.h:84)
==155342== by 0x10934B: main (main.cpp:30)
==155342==
==155342==
==155342== HEAP SUMMARY:
==155342== in use at exit: 0 bytes in 0 blocks
==155342== total heap usage: 14 allocs, 14 frees, 73,900 bytes allocated
==155342==
==155342== All heap blocks were freed -- no leaks are possible
==155342==
==155342== Use --track-origins=yes to see where uninitialised values come from
==155342== For lists of detected and suppressed errors, rerun with: -s
==155342== ERROR SUMMARY: 35 errors from 13 contexts (suppressed: 0 from 0)
valentina#valentina-Lenovo-Yoga-C740-14IML:~/Documentos/Algo II/Plantillvalentina#valentina-Lenovo-Yoga-C740-14IML:~/Documentos/Algo II/Plantillvalentina#valentina-Lenovo-Yoga-C740-14IML:~/Documentos/Algo II/Plantillvalentina#valentina-Lenovo-Yoga-C740-14IML:~/Documentos/Algo II/Plantillas de estructuras/graphTemplates$ v
algrind --tool=memcheck --xml=yes --xml-file=/tmp/valgrind --leak-check=full "./cmake-build-debug/graphTemplates"
========================= GRAPH ================================
Edge connecting 1 and 2 with cost 5 added successfully!
9999999 5
9999999 9999999
Edge connecting 1 and 2 with cost 4 added successfully!
Edge connecting 3 and 1 with cost 7 added successfully!
================================================================
valentina#valentina-Lenovo-Yoga-C740-14IML:~/Documentos/Algo II/Plantillas de estructuras/graphTemplates$ valgrind --tool=memcheck --track-origins=yes --leak-check=full "./cmake-build-debug/graphTemplates"==155816== Memcheck, a memory error detector
==155816== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==155816== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==155816== Command: ./cmake-build-debug/graphTemplates
==155816==
========================= GRAPH ================================
Edge connecting 1 and 2 with cost 5 added successfully!
9999999 5
9999999 9999999
Edge connecting 1 and 2 with cost 4 added successfully!
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x109BEC: Matrix<int>::resize(unsigned int) (Matrix.h:100)
==155816== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x109C0D: Matrix<int>::resize(unsigned int) (Matrix.h:103)
==155816== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x483C530: operator new[](unsigned long) (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==155816== by 0x109C1A: Matrix<int>::resize(unsigned int) (Matrix.h:103)
==155816== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x109C39: Matrix<int>::resize(unsigned int) (Matrix.h:104)
==155816== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x109C4B: Matrix<int>::resize(unsigned int) (Matrix.h:105)
==155816== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x483C530: operator new[](unsigned long) (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==155816== by 0x109C74: Matrix<int>::resize(unsigned int) (Matrix.h:105)
==155816== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x109C88: Matrix<int>::resize(unsigned int) (Matrix.h:107)
==155816== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x109D51: Matrix<int>::assignNull(unsigned int, unsigned int, unsigned int, unsigned int) (Matrix.h:122)
==155816== by 0x109CC8: Matrix<int>::resize(unsigned int) (Matrix.h:109)
==155816== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x109D5F: Matrix<int>::assignNull(unsigned int, unsigned int, unsigned int, unsigned int) (Matrix.h:123)
==155816== by 0x109CC8: Matrix<int>::resize(unsigned int) (Matrix.h:109)
==155816== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x109D51: Matrix<int>::assignNull(unsigned int, unsigned int, unsigned int, unsigned int) (Matrix.h:122)
==155816== by 0x109CE9: Matrix<int>::resize(unsigned int) (Matrix.h:110)
==155816== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x109D5F: Matrix<int>::assignNull(unsigned int, unsigned int, unsigned int, unsigned int) (Matrix.h:123)
==155816== by 0x109CE9: Matrix<int>::resize(unsigned int) (Matrix.h:110)
==155816== by 0x10974B: Graph<int, int>::addEdge(int, int, int) (Graph.h:119)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Use of uninitialised value of size 8
==155816== at 0x109A5E: Matrix<int>::insert(int, unsigned int, unsigned int) (Matrix.h:87)
==155816== by 0x109794: Graph<int, int>::addEdge(int, int, int) (Graph.h:121)
==155816== by 0x109327: main (main.cpp:36)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816== Conditional jump or move depends on uninitialised value(s)
==155816== at 0x109EB3: Matrix<int>::freeMatrixResources(int**) (Matrix.h:92)
==155816== by 0x109A99: Matrix<int>::~Matrix() (Matrix.h:77)
==155816== by 0x10958E: Graph<int, int>::~Graph() (Graph.h:84)
==155816== by 0x10934B: main (main.cpp:30)
==155816== Uninitialised value was created by a stack allocation
==155816== at 0x109289: main (main.cpp:7)
==155816==
==155816==
==155816== HEAP SUMMARY:
==155816== in use at exit: 0 bytes in 0 blocks
==155816== total heap usage: 14 allocs, 14 frees, 73,900 bytes allocated
==155816==
==155816== All heap blocks were freed -- no leaks are possible
==155816==
==155816== For lists of detected and suppressed errors, rerun with: -s
==155816== ERROR SUMMARY: 35 errors from 13 contexts (suppressed: 0 from 0)
Here are the methods in the Graph class which Valgrind complains
template<typename Type, typename Cost>
Graph<Type, Cost>:: ~Graph() {
delete costsMatrix;
delete vertices;
}
template<typename Type, typename Cost>
void Graph<Type, Cost>:: addEdge(Type begin, Type end, Cost cost) {
if (existsVertex(begin) && existsVertex(end)) {
costsMatrix->insert(cost, vertices->getPosition(begin), vertices->getPosition(end));
}
else if (existsVertex(begin)) {
costsMatrix->resize(elements + 1);
vertices->insertAtEnd(end);
costsMatrix->insert(cost, vertices->getPosition(begin), elements);
elements += 1;
}
else if(existsVertex(end)) {
costsMatrix->resize(elements + 1);
vertices->insertAtEnd(begin);
costsMatrix->insert(cost, elements, vertices->getPosition(end));
elements += 1;
}
else {
costsMatrix->resize(elements + 2);
vertices->insertAtEnd(begin);
vertices->insertAtEnd(end);
elements += 2;
costsMatrix->insert(cost, vertices->getPosition(begin), vertices->getPosition(end));
}
cout << "\t\tEdge connecting " << begin << " and " << end << " with cost " << cost << " added successfully!\n";
}
I know I could use std library for the matrix, but I was asked not to
Update: The problem was that in one of the paths I had, I was not initializing the attribute elements correctly. Thanks all for the help

Answer 1

The error says that there's an uninitialized value being used in a "conditional jump or move", which basically means a conditional statement such as if. It says that the error is happening the Matrix<int>::resize(unsigned int) method. So it must be referring to
if (this->size != newSize)
which means that either this->size or newSize is uninitialized.
Another valgrind error says that an uninitialized value is being used in operator new[](unsigned long) being called from the resize method. So that must be referring to
matrix = new Type*[newSize];
So this has narrowed down the problem to the newSize variable. This is a function parameter, so we have to step back to where the function is called. The stack trace says it was called from Graph<int, int>::addEdge(int, int, int). All the calls are similar to:
costsMatrix->resize(elements + 1);
so the problem must be that the elements variable is not initialized.