【发布时间】：2016-02-03 18:19:35
【问题描述】：
我目前正在调试我编写的使用 Bullet Physics 的 C/C++ 程序。我正在使用 g++ 4.8.4、valgrind 3.10.1 和 Bullet Physics 2.82 开发 Ubuntu 14.04.3。
我的编译命令（用于调试）是：
g++ -fno-inline -O0 -g -Wall -Wl,-rpath=./more_libs/lib,--enable-new-dtags -std=gnu++11 -I../bullet-2.82-r2704/Demos/OpenGL/ -I./more_libs/include/ -I../bullet-2.82-r2704/src/ ./main.cpp -L../bullet-2.82-r2704/Glut/ -L./more_libs/lib/ -L./more_libs/mesa -L../bullet-build/Demos/OpenGL/ -L../more_libs/lib/x86_64-linux-gnu -L../bullet-build/src/BulletDynamics/ -L../bullet-build/src/BulletCollision/ -L../bullet-build/src/LinearMath/ -lOpenGLSupport -lGL -lGLU -lglut -lBulletDynamics -lBulletCollision -lLinearMath -lXi -lXxf86vm -lX11 -o ./app
（调试和正常之间的区别在于 -O0 和 -fno-inline 选项。我正在添加库路径，因为我需要将此程序移植到我没有超级用户权限的集群。）
使用 Valgrind，我发现了大量类似的未初始化值错误，如下所示：
Conditional jump or move depends on uninitialised value(s)
at 0x4608C1: btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCollisionObject**, int, btPersistentManifold**, int, btTypedConstraint**, int, btContactSolverInfo const&, btIDebugDraw*) (in /home/josh/Documents/projects/evodevo_model/noise/EvoDevo-Modeling/evodevo/c++/app)
by 0x4591FC: btSequentialImpulseConstraintSolver::solveGroup(btCollisionObject**, int, btPersistentManifold**, int, btTypedConstraint**, int, btContactSolverInfo const&, btIDebugDraw*, btDispatcher*) (in /home/josh/Documents/projects/evodevo_model/noise/EvoDevo-Modeling/evodevo/c++/app)
by 0x46A3FF: btDiscreteDynamicsWorld::solveConstraints(btContactSolverInfo&) (in /home/josh/Documents/projects/evodevo_model/noise/EvoDevo-Modeling/evodevo/c++/app)
by 0x467584: btDiscreteDynamicsWorld::internalSingleStepSimulation(float) (in /home/josh/Documents/projects/evodevo_model/noise/EvoDevo-Modeling/evodevo/c++/app)
by 0x465459: btDiscreteDynamicsWorld::stepSimulation(float, int, float) (in /home/josh/Documents/projects/evodevo_model/noise/EvoDevo-Modeling/evodevo/c++/app)
by 0x4088F4: NoiseWorld::clientMoveAndDisplay() (NoiseWorld.cpp:288)
by 0x409A28: main (main.cpp:46)
Uninitialised value was created by a heap allocation
at 0x4C2ABBD: malloc (vg_replace_malloc.c:296)
by 0x4EE043: btAlignedAllocDefault(unsigned long, int) (in /home/josh/Documents/projects/evodevo_model/noise/EvoDevo-Modeling/evodevo/c++/app)
by 0x40BC09: btHingeConstraint::operator new(unsigned long) (btHingeConstraint.h:103)
by 0x40CF73: NoiseWorld::CreateHinge(int, int, int, float, float, float, float, float, float, float, float, bool) (NoiseWorld.h:332)
by 0x40807C: NoiseWorld::initPhysics() (NoiseWorld.cpp:193)
by 0x4099F4: main (main.cpp:41)
我试图查看solveGroupCacheFriendlySetup() 发生了什么，但是当我在那里设置断点并运行GDB 时，程序并没有停止——它只是运行完成。我已经按函数和内存设置了断点（在 valgrind 检查中是恒定的），但没有一个被找到/使用。
那么，问题来了：在程序运行期间如何查看solveGroupCacheFriendlySetup() 中发生了什么？从那里，我想我将能够找出未初始化的内容。
如果这是一个简单的问题，请提前抱歉，但过去两天我一直无法找到答案。我是一个新手程序员，我已经承担了一个大项目，所以我猜我做错了一些简单的事情，但我现在不知道具体要问什么。
编辑： 根据 πάντα ῥεῖ 的建议，这是我在运行时需要查看的功能。这个函数的在线文档可以在这里找到：http://bulletphysics.org/Bullet/BulletFull/classbtSequentialImpulseConstraintSolver.html
注意：这部分代码不是我写的，我也不是 100% 做的。我很确定错误出在其他地方。我没有很好地设置物理模拟器环境。
此外，我不知道 valgrind 消息“（在 /home/josh/Documents/projects/evodevo_model/noise/EvoDevo-Modeling/evodevo/c++/app 中）”在尝试添加断点方面意味着什么GDB在运行程序时可以找到。
btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCollisionObject** bodies, int numBodies, btPersistentManifold** manifoldPtr, int numManifolds,btTypedConstraint** constraints,int numConstraints,const btContactSolverInfo& infoGlobal,btIDebugDraw* debugDrawer)
{
m_fixedBodyId = -1;
BT_PROFILE("solveGroupCacheFriendlySetup");
(void)debugDrawer;
m_maxOverrideNumSolverIterations = 0;
#ifdef BT_ADDITIONAL_DEBUG
//make sure that dynamic bodies exist for all (enabled) constraints
for (int i=0;i<numConstraints;i++)
{
btTypedConstraint* constraint = constraints[i];
if (constraint->isEnabled())
{
if (!constraint->getRigidBodyA().isStaticOrKinematicObject())
{
bool found=false;
for (int b=0;b<numBodies;b++)
{
if (&constraint->getRigidBodyA()==bodies[b])
{
found = true;
break;
}
}
btAssert(found);
}
if (!constraint->getRigidBodyB().isStaticOrKinematicObject())
{
bool found=false;
for (int b=0;b<numBodies;b++)
{
if (&constraint->getRigidBodyB()==bodies[b])
{
found = true;
break;
}
}
btAssert(found);
}
}
}
//make sure that dynamic bodies exist for all contact manifolds
for (int i=0;i<numManifolds;i++)
{
if (!manifoldPtr[i]->getBody0()->isStaticOrKinematicObject())
{
bool found=false;
for (int b=0;b<numBodies;b++)
{
if (manifoldPtr[i]->getBody0()==bodies[b])
{
found = true;
break;
}
}
btAssert(found);
}
if (!manifoldPtr[i]->getBody1()->isStaticOrKinematicObject())
{
bool found=false;
for (int b=0;b<numBodies;b++)
{
if (manifoldPtr[i]->getBody1()==bodies[b])
{
found = true;
break;
}
}
btAssert(found);
}
}
#endif //BT_ADDITIONAL_DEBUG
for (int i = 0; i < numBodies; i++)
{
bodies[i]->setCompanionId(-1);
}
m_tmpSolverBodyPool.reserve(numBodies+1);
m_tmpSolverBodyPool.resize(0);
//btSolverBody& fixedBody = m_tmpSolverBodyPool.expand();
//initSolverBody(&fixedBody,0);
//convert all bodies
for (int i=0;i<numBodies;i++)
{
int bodyId = getOrInitSolverBody(*bodies[i],infoGlobal.m_timeStep);
btRigidBody* body = btRigidBody::upcast(bodies[i]);
if (body && body->getInvMass())
{
btSolverBody& solverBody = m_tmpSolverBodyPool[bodyId];
btVector3 gyroForce (0,0,0);
if (body->getFlags()&BT_ENABLE_GYROPSCOPIC_FORCE)
{
gyroForce = body->computeGyroscopicForce(infoGlobal.m_maxGyroscopicForce);
solverBody.m_externalTorqueImpulse -= gyroForce*body->getInvInertiaTensorWorld()*infoGlobal.m_timeStep;
}
}
}
if (1)
{
int j;
for (j=0;j<numConstraints;j++)
{
btTypedConstraint* constraint = constraints[j];
constraint->buildJacobian();
constraint->internalSetAppliedImpulse(0.0f);
}
}
//btRigidBody* rb0=0,*rb1=0;
//if (1)
{
{
int totalNumRows = 0;
int i;
m_tmpConstraintSizesPool.resizeNoInitialize(numConstraints);
//calculate the total number of contraint rows
for (i=0;i<numConstraints;i++)
{
btTypedConstraint::btConstraintInfo1& info1 = m_tmpConstraintSizesPool[i];
btJointFeedback* fb = constraints[i]->getJointFeedback();
if (fb)
{
fb->m_appliedForceBodyA.setZero();
fb->m_appliedTorqueBodyA.setZero();
fb->m_appliedForceBodyB.setZero();
fb->m_appliedTorqueBodyB.setZero();
}
if (constraints[i]->isEnabled())
{
}
if (constraints[i]->isEnabled())
{
constraints[i]->getInfo1(&info1);
} else
{
info1.m_numConstraintRows = 0;
info1.nub = 0;
}
totalNumRows += info1.m_numConstraintRows;
}
m_tmpSolverNonContactConstraintPool.resizeNoInitialize(totalNumRows);
///setup the btSolverConstraints
int currentRow = 0;
for (i=0;i<numConstraints;i++)
{
const btTypedConstraint::btConstraintInfo1& info1 = m_tmpConstraintSizesPool[i];
if (info1.m_numConstraintRows)
{
btAssert(currentRow<totalNumRows);
btSolverConstraint* currentConstraintRow = &m_tmpSolverNonContactConstraintPool[currentRow];
btTypedConstraint* constraint = constraints[i];
btRigidBody& rbA = constraint->getRigidBodyA();
btRigidBody& rbB = constraint->getRigidBodyB();
int solverBodyIdA = getOrInitSolverBody(rbA,infoGlobal.m_timeStep);
int solverBodyIdB = getOrInitSolverBody(rbB,infoGlobal.m_timeStep);
btSolverBody* bodyAPtr = &m_tmpSolverBodyPool[solverBodyIdA];
btSolverBody* bodyBPtr = &m_tmpSolverBodyPool[solverBodyIdB];
int overrideNumSolverIterations = constraint->getOverrideNumSolverIterations() > 0 ? constraint->getOverrideNumSolverIterations() : infoGlobal.m_numIterations;
if (overrideNumSolverIterations>m_maxOverrideNumSolverIterations)
m_maxOverrideNumSolverIterations = overrideNumSolverIterations;
int j;
for ( j=0;j<info1.m_numConstraintRows;j++)
{
memset(¤tConstraintRow[j],0,sizeof(btSolverConstraint));
currentConstraintRow[j].m_lowerLimit = -SIMD_INFINITY;
currentConstraintRow[j].m_upperLimit = SIMD_INFINITY;
currentConstraintRow[j].m_appliedImpulse = 0.f;
currentConstraintRow[j].m_appliedPushImpulse = 0.f;
currentConstraintRow[j].m_solverBodyIdA = solverBodyIdA;
currentConstraintRow[j].m_solverBodyIdB = solverBodyIdB;
currentConstraintRow[j].m_overrideNumSolverIterations = overrideNumSolverIterations;
}
bodyAPtr->internalGetDeltaLinearVelocity().setValue(0.f,0.f,0.f);
bodyAPtr->internalGetDeltaAngularVelocity().setValue(0.f,0.f,0.f);
bodyAPtr->internalGetPushVelocity().setValue(0.f,0.f,0.f);
bodyAPtr->internalGetTurnVelocity().setValue(0.f,0.f,0.f);
bodyBPtr->internalGetDeltaLinearVelocity().setValue(0.f,0.f,0.f);
bodyBPtr->internalGetDeltaAngularVelocity().setValue(0.f,0.f,0.f);
bodyBPtr->internalGetPushVelocity().setValue(0.f,0.f,0.f);
bodyBPtr->internalGetTurnVelocity().setValue(0.f,0.f,0.f);
btTypedConstraint::btConstraintInfo2 info2;
info2.fps = 1.f/infoGlobal.m_timeStep;
info2.erp = infoGlobal.m_erp;
info2.m_J1linearAxis = currentConstraintRow->m_contactNormal1;
info2.m_J1angularAxis = currentConstraintRow->m_relpos1CrossNormal;
info2.m_J2linearAxis = currentConstraintRow->m_contactNormal2;
info2.m_J2angularAxis = currentConstraintRow->m_relpos2CrossNormal;
info2.rowskip = sizeof(btSolverConstraint)/sizeof(btScalar);//check this
///the size of btSolverConstraint needs be a multiple of btScalar
btAssert(info2.rowskip*sizeof(btScalar)== sizeof(btSolverConstraint));
info2.m_constraintError = ¤tConstraintRow->m_rhs;
currentConstraintRow->m_cfm = infoGlobal.m_globalCfm;
info2.m_damping = infoGlobal.m_damping;
info2.cfm = ¤tConstraintRow->m_cfm;
info2.m_lowerLimit = ¤tConstraintRow->m_lowerLimit;
info2.m_upperLimit = ¤tConstraintRow->m_upperLimit;
info2.m_numIterations = infoGlobal.m_numIterations;
constraints[i]->getInfo2(&info2);
///finalize the constraint setup
for ( j=0;j<info1.m_numConstraintRows;j++)
{
btSolverConstraint& solverConstraint = currentConstraintRow[j];
if (solverConstraint.m_upperLimit>=constraints[i]->getBreakingImpulseThreshold())
{
solverConstraint.m_upperLimit = constraints[i]->getBreakingImpulseThreshold();
}
if (solverConstraint.m_lowerLimit<=-constraints[i]->getBreakingImpulseThreshold())
{
solverConstraint.m_lowerLimit = -constraints[i]->getBreakingImpulseThreshold();
}
solverConstraint.m_originalContactPoint = constraint;
{
const btVector3& ftorqueAxis1 = solverConstraint.m_relpos1CrossNormal;
solverConstraint.m_angularComponentA = constraint->getRigidBodyA().getInvInertiaTensorWorld()*ftorqueAxis1*constraint->getRigidBodyA().getAngularFactor();
}
{
const btVector3& ftorqueAxis2 = solverConstraint.m_relpos2CrossNormal;
solverConstraint.m_angularComponentB = constraint->getRigidBodyB().getInvInertiaTensorWorld()*ftorqueAxis2*constraint->getRigidBodyB().getAngularFactor();
}
{
btVector3 iMJlA = solverConstraint.m_contactNormal1*rbA.getInvMass();
btVector3 iMJaA = rbA.getInvInertiaTensorWorld()*solverConstraint.m_relpos1CrossNormal;
btVector3 iMJlB = solverConstraint.m_contactNormal2*rbB.getInvMass();//sign of normal?
btVector3 iMJaB = rbB.getInvInertiaTensorWorld()*solverConstraint.m_relpos2CrossNormal;
btScalar sum = iMJlA.dot(solverConstraint.m_contactNormal1);
sum += iMJaA.dot(solverConstraint.m_relpos1CrossNormal);
sum += iMJlB.dot(solverConstraint.m_contactNormal2);
sum += iMJaB.dot(solverConstraint.m_relpos2CrossNormal);
btScalar fsum = btFabs(sum);
btAssert(fsum > SIMD_EPSILON);
solverConstraint.m_jacDiagABInv = fsum>SIMD_EPSILON?btScalar(1.)/sum : 0.f;
}
{
btScalar rel_vel;
btVector3 externalForceImpulseA = bodyAPtr->m_originalBody ? bodyAPtr->m_externalForceImpulse : btVector3(0,0,0);
btVector3 externalTorqueImpulseA = bodyAPtr->m_originalBody ? bodyAPtr->m_externalTorqueImpulse : btVector3(0,0,0);
btVector3 externalForceImpulseB = bodyBPtr->m_originalBody ? bodyBPtr->m_externalForceImpulse : btVector3(0,0,0);
btVector3 externalTorqueImpulseB = bodyBPtr->m_originalBody ?bodyBPtr->m_externalTorqueImpulse : btVector3(0,0,0);
btScalar vel1Dotn = solverConstraint.m_contactNormal1.dot(rbA.getLinearVelocity()+externalForceImpulseA)
+ solverConstraint.m_relpos1CrossNormal.dot(rbA.getAngularVelocity()+externalTorqueImpulseA);
btScalar vel2Dotn = solverConstraint.m_contactNormal2.dot(rbB.getLinearVelocity()+externalForceImpulseB)
+ solverConstraint.m_relpos2CrossNormal.dot(rbB.getAngularVelocity()+externalTorqueImpulseB);
rel_vel = vel1Dotn+vel2Dotn;
btScalar restitution = 0.f;
btScalar positionalError = solverConstraint.m_rhs;//already filled in by getConstraintInfo2
btScalar velocityError = restitution - rel_vel * info2.m_damping;
btScalar penetrationImpulse = positionalError*solverConstraint.m_jacDiagABInv;
btScalar velocityImpulse = velocityError *solverConstraint.m_jacDiagABInv;
solverConstraint.m_rhs = penetrationImpulse+velocityImpulse;
solverConstraint.m_appliedImpulse = 0.f;
}
}
}
currentRow+=m_tmpConstraintSizesPool[i].m_numConstraintRows;
}
}
convertContacts(manifoldPtr,numManifolds,infoGlobal);
}
// btContactSolverInfo info = infoGlobal;
int numNonContactPool = m_tmpSolverNonContactConstraintPool.size();
int numConstraintPool = m_tmpSolverContactConstraintPool.size();
int numFrictionPool = m_tmpSolverContactFrictionConstraintPool.size();
///@todo: use stack allocator for such temporarily memory, same for solver bodies/constraints
m_orderNonContactConstraintPool.resizeNoInitialize(numNonContactPool);
if ((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS))
m_orderTmpConstraintPool.resizeNoInitialize(numConstraintPool*2);
else
m_orderTmpConstraintPool.resizeNoInitialize(numConstraintPool);
m_orderFrictionConstraintPool.resizeNoInitialize(numFrictionPool);
{
int i;
for (i=0;i<numNonContactPool;i++)
{
m_orderNonContactConstraintPool[i] = i;
}
for (i=0;i<numConstraintPool;i++)
{
m_orderTmpConstraintPool[i] = i;
}
for (i=0;i<numFrictionPool;i++)
{
m_orderFrictionConstraintPool[i] = i;
}
}
return 0.f;
}
【问题讨论】：
-
恐怕我们无法在信息范围狭窄的情况下给您一个简明的答案。至少显示
solveGroupCacheFriendlySetup()以及您设置断点的位置。 -
@πάνταῥεῖ 我添加了代码，但是，正如我在笔记中提到的，我认为这不是错误所在。根据 valgrind 的说法，我错误地初始化了物理模拟器中连接形状的铰链；只是这些值在solveGroupCacheFriendlySetup() 中使用。我很困惑如何解释 valgrind 消息的“（在 /home/josh/Documents/projects/evodevo_model/noise/EvoDevo-Modeling/evodevo/c++/app）”部分。
-
我猜你正在链接到一个静态发布库，它根本不会中断，除非你进入汇编。如果您可以链接到包含调试信息的调试版本，至少在 Windows 平台上，这允许调试器中断该函数。
-
感谢@StarShine，确保我链接到动态库是解决方案的一部分。
-
@StarShine 如果您将您的评论作为答案发表，我会很乐意接受它以给予您适当的信任。虽然用户 phd 提供了帮助，但我已经知道该功能；您的意见是真正的游戏规则改变者。
标签： c++ gdb valgrind breakpoints