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coreaction.cc
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/* ###
* IP: GHIDRA
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "coreaction.hh"
#include "condexe.hh"
#include "double.hh"
#include "subflow.hh"
/// \brief A stack equation
struct StackEqn {
int4 var1; ///< Variable with 1 coefficient
int4 var2; ///< Variable with -1 coefficient
int4 rhs; ///< Right hand side of the equation
static bool compare(const StackEqn &a,const StackEqn &b); ///< Order two equations
};
/// \brief A class that solves for stack-pointer changes across unknown sub-functions
class StackSolver {
vector<StackEqn> eqs; ///< Known equations based on operations that explicitly change the stack-pointer
vector<StackEqn> guess; ///< Guessed equations for underdetermined systems
vector<Varnode *> vnlist; ///< The indexed set of variables, one for each reference to the stack-pointer
vector<int4> companion; ///< Index of companion input for variable produced by CPUI_INDIRECT
Address spacebase; ///< Starting address of the stack-pointer
vector<int4> soln; ///< Collected solutions (corresponding to array of variables)
int4 missedvariables; ///< Number of variables for which we are missing an equation
void duplicate(void); ///< Duplicate each equation, multiplying by -1
void propagate(int4 varnum,int4 val); ///< Propagate solution for one variable to other variables
public:
void solve(void); ///< Solve the system of equations
void build(const Funcdata &data,AddrSpace *id,int4 spcbase); ///< Build the system of equations
int4 getNumVariables(void) const { return vnlist.size(); } ///< Get the number of variables in the system
Varnode *getVariable(int4 i) const { return vnlist[i]; } ///< Get the i-th Varnode variable
int4 getCompanion(int4 i) const { return companion[i]; } ///< Get the i-th variable's companion index
int4 getSolution(int4 i) const { return soln[i]; } ///< Get the i-th variable's solution
};
/// \param a is the first equation to compare
/// \param b is the second
/// \return true if the first equation comes before the second
bool StackEqn::compare(const StackEqn &a,const StackEqn &b)
{
return (a.var1<b.var1);
}
/// Given a solution for one variable, look for equations containing the variable
/// and attempt to solve for the other variable. Continue propagating new
/// solutions to other equations to find even more solutions. Populate
/// the \b soln array with the solutions.
/// \param varnum is the index of the initial variable
/// \param val is the solution for the variable
void StackSolver::propagate(int4 varnum,int4 val)
{
if (soln[varnum] != 65535) return; // This variable already specified
soln[varnum] = val;
StackEqn eqn;
vector<int4> workstack;
workstack.reserve(soln.size());
workstack.push_back(varnum);
vector<StackEqn>::iterator top;
while(!workstack.empty()) {
varnum = workstack.back();
workstack.pop_back();
eqn.var1 = varnum;
top = lower_bound(eqs.begin(),eqs.end(),eqn,StackEqn::compare);
while((top!=eqs.end())&&((*top).var1 == varnum)) {
int4 var2 = (*top).var2;
if (soln[var2] == 65535) {
soln[var2] = soln[varnum]-(*top).rhs;
workstack.push_back(var2);
}
++top;
}
}
}
void StackSolver::duplicate(void)
{
int4 size,i;
StackEqn eqn;
size = eqs.size();
for(i=0;i<size;++i) {
eqn.var1 = eqs[i].var2;
eqn.var2 = eqs[i].var1;
eqn.rhs = -eqs[i].rhs;
eqs.push_back(eqn);
}
stable_sort(eqs.begin(),eqs.end(),StackEqn::compare);
}
void StackSolver::solve(void)
{
// Use guesses to resolve subsystems not uniquely determined
int4 i,size,var1,var2,count,lastcount;
soln.clear();
soln.resize(vnlist.size(),65535); // Initialize solutions vector
duplicate(); // Duplicate and sort the equations
propagate(0,0); // We know one variable
size = guess.size();
lastcount = size+2;
do {
count = 0;
for(i=0;i<size;++i) {
var1 = guess[i].var1;
var2 = guess[i].var2;
if ((soln[var1]!=65535)&&(soln[var2]==65535))
propagate(var2,soln[var1]-guess[i].rhs);
else if ((soln[var1]==65535)&&(soln[var2]!=65535))
propagate(var1,soln[var2]+guess[i].rhs);
else if ((soln[var1]==65535)&&(soln[var2]==65535))
count += 1;
}
if (count == lastcount) break;
lastcount = count;
} while(count > 0);
}
/// Collect references to the stack-pointer as variables, and examine their defining PcodeOps
/// to determine equations and coefficient.
/// \param data is the function being analyzed
/// \param id is the \e stack address space
/// \param spcbase is the index, relative to the stack space, of the stack pointer
void StackSolver::build(const Funcdata &data,AddrSpace *id,int4 spcbase)
{
const VarnodeData &spacebasedata(id->getSpacebase(spcbase));
spacebase = Address(spacebasedata.space,spacebasedata.offset);
VarnodeLocSet::const_iterator begiter,enditer;
begiter = data.beginLoc(spacebasedata.size,spacebase);
enditer = data.endLoc(spacebasedata.size,spacebase);
while(begiter != enditer) { // All instances of the spacebase
if ((*begiter)->isFree()) break;
vnlist.push_back(*begiter);
companion.push_back(-1);
++begiter;
}
missedvariables = 0;
if (vnlist.empty()) return;
if (!vnlist[0]->isInput())
throw LowlevelError("Input value of stackpointer is not used");
vector<Varnode *>::iterator iter;
StackEqn eqn;
for(int4 i=1;i<vnlist.size();++i) {
Varnode *vn = vnlist[i];
Varnode *othervn,*constvn;
PcodeOp *op = vn->getDef();
if (op->code() == CPUI_INT_ADD) {
othervn = op->getIn(0);
constvn = op->getIn(1);
if (othervn->isConstant()) {
constvn = othervn;
othervn = op->getIn(1);
}
if (!constvn->isConstant()) { missedvariables+=1; continue; }
if (othervn->getAddr() != spacebase) { missedvariables+=1; continue; }
iter = lower_bound(vnlist.begin(),vnlist.end(),othervn,Varnode::comparePointers);
eqn.var1 = i;
eqn.var2 = iter-vnlist.begin();
eqn.rhs = constvn->getOffset();
eqs.push_back(eqn);
}
else if (op->code() == CPUI_COPY) {
othervn = op->getIn(0);
if (othervn->getAddr() != spacebase) { missedvariables+=1; continue; }
iter = lower_bound(vnlist.begin(),vnlist.end(),othervn,Varnode::comparePointers);
eqn.var1 = i;
eqn.var2 = iter-vnlist.begin();
eqn.rhs = 0;
eqs.push_back(eqn);
}
else if (op->code() == CPUI_INDIRECT) {
othervn = op->getIn(0);
if (othervn->getAddr() != spacebase) { missedvariables += 1; continue; }
iter = lower_bound(vnlist.begin(),vnlist.end(),othervn,Varnode::comparePointers);
eqn.var1 = i;
eqn.var2 = iter-vnlist.begin();
companion[i] = eqn.var2;
Varnode *iopvn = op->getIn(1);
if (iopvn->getSpace()->getType()==IPTR_IOP) { // If INDIRECT is due call
PcodeOp *iop = PcodeOp::getOpFromConst(iopvn->getAddr());
FuncCallSpecs *fc = data.getCallSpecs(iop); // Look up function proto
if (fc != (FuncCallSpecs *)0) {
if (fc->getExtraPop() != ProtoModel::extrapop_unknown) { // Double check that extrapop is unknown
eqn.rhs = fc->getExtraPop(); // As the deindirect process may have filled it in
eqs.push_back(eqn);
continue;
}
}
}
eqn.rhs = 4; // Otherwise make a guess
guess.push_back(eqn);
}
else if (op->code() == CPUI_MULTIEQUAL) {
for(int4 j=0;j<op->numInput();++j) {
othervn = op->getIn(j);
if (othervn->getAddr() != spacebase) { missedvariables += 1; continue; }
iter = lower_bound(vnlist.begin(),vnlist.end(),othervn,Varnode::comparePointers);
eqn.var1 = i;
eqn.var2 = iter-vnlist.begin();
eqn.rhs = 0;
eqs.push_back(eqn);
}
}
else if (op->code() == CPUI_INT_AND) {
// This can occur if a function aligns its stack pointer
othervn = op->getIn(0);
constvn = op->getIn(1);
if (othervn->isConstant()) {
constvn = othervn;
othervn = op->getIn(1);
}
if (!constvn->isConstant()) { missedvariables+=1; continue; }
if (othervn->getAddr() != spacebase) { missedvariables+=1; continue; }
iter = lower_bound(vnlist.begin(),vnlist.end(),othervn,Varnode::comparePointers);
eqn.var1 = i;
eqn.var2 = iter-vnlist.begin();
eqn.rhs = 0; // Treat this as a copy
eqs.push_back(eqn);
}
else
missedvariables += 1;
}
}
/// \brief Calculate stack-pointer change across \e undetermined sub-functions
///
/// If there are sub-functions for which \e extra \e pop is not explicit,
/// do full linear analysis to (attempt to) recover the values.
/// \param data is the function to analyze
/// \param stackspace is the space associated with the stack-pointer
/// \param spcbase is the index (relative to the stackspace) of the stack-pointer
void ActionStackPtrFlow::analyzeExtraPop(Funcdata &data,AddrSpace *stackspace,int4 spcbase)
{
ProtoModel *myfp = data.getArch()->evalfp_called;
if (myfp == (ProtoModel *)0)
myfp = data.getArch()->defaultfp;
if (myfp->getExtraPop()!=ProtoModel::extrapop_unknown) return;
StackSolver solver;
try {
solver.build(data,stackspace,spcbase);
} catch(LowlevelError &err) {
ostringstream s;
s << "Stack frame is not setup normally: " << err.explain;
data.warningHeader(s.str());
return;
}
if (solver.getNumVariables() == 0) return;
solver.solve(); // Solve the equations
Varnode *invn = solver.getVariable(0);
bool warningprinted = false;
for(int4 i=1;i<solver.getNumVariables();++i) {
Varnode *vn = solver.getVariable(i);
int4 soln = solver.getSolution(i);
if (soln == 65535) {
if (!warningprinted) {
data.warningHeader("Unable to track spacebase fully for "+stackspace->getName());
warningprinted = true;
}
continue;
}
PcodeOp *op = vn->getDef();
if (op->code() == CPUI_INDIRECT) {
Varnode *iopvn = op->getIn(1);
if (iopvn->getSpace()->getType()==IPTR_IOP) {
PcodeOp *iop = PcodeOp::getOpFromConst(iopvn->getAddr());
FuncCallSpecs *fc = data.getCallSpecs(iop);
if (fc != (FuncCallSpecs *)0) {
int4 soln2 = 0;
int4 comp = solver.getCompanion(i);
if (comp >= 0)
soln2 = solver.getSolution(comp);
fc->setEffectiveExtraPop(soln-soln2);
}
}
}
vector<Varnode *> paramlist;
paramlist.push_back(invn);
int4 sz = invn->getSize();
paramlist.push_back(data.newConstant(sz,soln&calc_mask(sz)));
data.opSetOpcode(op,CPUI_INT_ADD);
data.opSetAllInput(op,paramlist);
}
return;
}
/// \brief Is the given Varnode defined as a pointer relative to the stack-pointer?
///
/// Return true if -vn- is defined as the stackpointer input plus a constant (or zero)
/// This works through the general case and the special case when the constant is zero.
/// The constant value is passed-back to the caller.
/// \param spcbasein is the Varnode holding the \e input value of the stack-pointer
/// \param vn is the Varnode to check for relativeness
/// \param constval is a reference for passing back the constant offset
/// \return true if \b vn is stack relative
bool ActionStackPtrFlow::isStackRelative(Varnode *spcbasein,Varnode *vn,uintb &constval)
{
if (spcbasein == vn) {
constval = 0;
return true;
}
if (!vn->isWritten()) return false;
PcodeOp *addop = vn->getDef();
if (addop->code() != CPUI_INT_ADD) return false;
if (addop->getIn(0) != spcbasein) return false;
Varnode *constvn = addop->getIn(1);
if (!constvn->isConstant()) return false;
constval = constvn->getOffset();
return true;
}
/// \brief Adjust the LOAD where the stack-pointer alias has been recovered.
///
/// We've matched a LOAD with its matching store, now convert the LOAD op to a COPY of what was stored.
/// \param data is the function being analyzed
/// \param loadop is the LOAD op to adjust
/// \param storeop is the matching STORE op
/// \return true if the adjustment is successful
bool ActionStackPtrFlow::adjustLoad(Funcdata &data,PcodeOp *loadop,PcodeOp *storeop)
{
Varnode *vn = storeop->getIn(2);
if (vn->isConstant())
vn = data.newConstant(vn->getSize(),vn->getOffset());
else if (vn->isFree())
return false;
data.opRemoveInput(loadop,1);
data.opSetOpcode(loadop,CPUI_COPY);
data.opSetInput(loadop,vn,0);
return true;
}
/// \brief Link LOAD to matching STORE of a constant
///
/// Try to find STORE op using same stack relative pointer as a given LOAD op.
/// If we find it and the STORE stores a constant, change the LOAD to a COPY.
/// \param data is the function owning the LOAD
/// \param id is the stackspace
/// \param spcbasein is the stack-pointer
/// \param loadop is the given LOAD op
/// \param constz is the stack relative offset of the LOAD pointer
/// \return 1 if we successfully change LOAD to COPY, 0 otherwise
int4 ActionStackPtrFlow::repair(Funcdata &data,AddrSpace *id,Varnode *spcbasein,PcodeOp *loadop,uintb constz)
{
int4 loadsize = loadop->getOut()->getSize();
BlockBasic *curblock = loadop->getParent();
list<PcodeOp *>::iterator begiter = curblock->beginOp();
list<PcodeOp *>::iterator iter = loadop->getBasicIter();
for(;;) {
if (iter == begiter) {
if (curblock->sizeIn() != 1) return 0; // Can trace back to next basic block if only one path
curblock = (BlockBasic *)curblock->getIn(0);
begiter = curblock->beginOp();
iter = curblock->endOp();
continue;
}
else {
--iter;
}
PcodeOp *curop = *iter;
if (curop->isCall()) return 0; // Don't try to trace aliasing through a call
if (curop->code() == CPUI_STORE) {
Varnode *ptrvn = curop->getIn(1);
Varnode *datavn = curop->getIn(2);
uintb constnew;
if (isStackRelative(spcbasein,ptrvn,constnew)) {
if ((constnew == constz)&&(loadsize == datavn->getSize())) {
// We found the matching store
if (adjustLoad(data,loadop,curop))
return 1;
return 0;
}
else if ((constnew <= constz + (loadsize-1))&&(constnew+(datavn->getSize()-1)>=constz))
return 0;
}
else
return 0; // Any other kind of STORE we can't solve aliasing
}
else {
Varnode *outvn = curop->getOut();
if (outvn != (Varnode *)0) {
if (outvn->getSpace() == id) return 0; // Stack already traced, too late
}
}
}
}
/// \brief Find any stack pointer clogs and pass it on to the repair routines
///
/// A stack pointer \b clog is a constant addition to the stack-pointer,
/// but where the constant comes from the stack.
/// \param data is the function to analyze
/// \param id is the stack space
/// \param spcbase is the index of the stack-pointer relative to the stack space
/// \return the number of clogs that were repaired
int4 ActionStackPtrFlow::checkClog(Funcdata &data,AddrSpace *id,int4 spcbase)
{
const VarnodeData &spacebasedata(id->getSpacebase(spcbase));
Address spacebase = Address(spacebasedata.space,spacebasedata.offset);
VarnodeLocSet::const_iterator begiter,enditer;
int4 clogcount = 0;
begiter = data.beginLoc(spacebasedata.size,spacebase);
enditer = data.endLoc(spacebasedata.size,spacebase);
Varnode *spcbasein;
if (begiter == enditer) return clogcount;
spcbasein = *begiter;
++begiter;
if (!spcbasein->isInput()) return clogcount;
while(begiter != enditer) {
Varnode *outvn = *begiter;
++begiter;
if (!outvn->isWritten()) continue;
PcodeOp *addop = outvn->getDef();
if (addop->code() != CPUI_INT_ADD) continue;
Varnode *y = addop->getIn(1);
if (!y->isWritten()) continue; // y must not be a constant
Varnode *x = addop->getIn(0); // is y is not constant than x (in position 0) isn't either
uintb constx;
if (!isStackRelative(spcbasein,x,constx)) { // If x is not stack relative
x = y; // Swap x and y
y = addop->getIn(0);
if (!isStackRelative(spcbasein,x,constx)) continue; // Now maybe the new x is stack relative
}
PcodeOp *loadop = y->getDef();
if (loadop->code() == CPUI_INT_MULT) { // If we multiply
Varnode *constvn = loadop->getIn(1);
if (!constvn->isConstant()) continue;
if (constvn->getOffset() != calc_mask(constvn->getSize())) continue; // Must multiply by -1
y = loadop->getIn(0);
if (!y->isWritten()) continue;
loadop = y->getDef();
}
if (loadop->code() != CPUI_LOAD) continue;
Varnode *ptrvn = loadop->getIn(1);
uintb constz;
if (!isStackRelative(spcbasein,ptrvn,constz)) continue;
clogcount += repair(data,id,spcbasein,loadop,constz);
}
return clogcount;
}
int4 ActionStackPtrFlow::apply(Funcdata &data)
{
if (analysis_finished)
return 0;
if (stackspace == (AddrSpace *)0) {
analysis_finished = true; // No stack to do analysis on
return 0;
}
int4 numchange = checkClog(data,stackspace,0);
if (numchange > 0) {
count += 1;
}
if (numchange == 0) {
analyzeExtraPop(data,stackspace,0);
analysis_finished = true;
}
return 0;
}
/// \brief Examine the PcodeOps using the given Varnode to determine possible lane sizes
///
/// Run through the defining op and any descendant ops of the given Varnode, looking for
/// CPUI_PIECE and CPUI_SUBPIECE. Use these to determine possible lane sizes and
/// register them with the given LanedRegister object.
/// \param vn is the given Varnode
/// \param allowedLanes is used to determine if a putative lane size is allowed
/// \param checkLanes collects the possible lane sizes
void ActionLaneDivide::collectLaneSizes(Varnode *vn,const LanedRegister &allowedLanes,LanedRegister &checkLanes)
{
list<PcodeOp *>::const_iterator iter = vn->beginDescend();
int4 step = 0; // 0 = descendants, 1 = def, 2 = done
if (iter == vn->endDescend()) {
step = 1;
}
while(step < 2) {
int4 curSize; // Putative lane size
if (step == 0) {
PcodeOp *op = *iter;
++iter;
if (iter == vn->endDescend())
step = 1;
if (op->code() != CPUI_SUBPIECE) continue; // Is the big register split into pieces
curSize = op->getOut()->getSize();
}
else {
step = 2;
if (!vn->isWritten()) continue;
PcodeOp *op = vn->getDef();
if (op->code() != CPUI_PIECE) continue; // Is the big register formed from smaller pieces
curSize = op->getIn(0)->getSize();
int4 tmpSize = op->getIn(1)->getSize();
if (tmpSize < curSize)
curSize = tmpSize;
}
if (allowedLanes.allowedLane(curSize))
checkLanes.addLaneSize(curSize); // Register this possible size
}
}
/// \brief Search for a likely lane size and try to divide a single Varnode into these lanes
///
/// There are different ways to search for a lane size:
///
/// Mode 0: Collect putative lane sizes based on the local ops using the Varnode. Attempt
/// to divide based on each of those lane sizes in turn.
///
/// Mode 1: Similar to mode 0, except we allow for SUBPIECE operations that truncate to
/// variables that are smaller than the lane size.
///
/// Mode 2: Attempt to divide based on a default lane size.
/// \param data is the function being transformed
/// \param vn is the given single Varnode
/// \param lanedRegister is acceptable set of lane sizes for the Varnode
/// \param mode is the lane size search mode (0, 1, or 2)
/// \return \b true if the Varnode (and its data-flow) was successfully split
bool ActionLaneDivide::processVarnode(Funcdata &data,Varnode *vn,const LanedRegister &lanedRegister,int4 mode)
{
LanedRegister checkLanes; // Lanes we are going to try, initialized to no lanes
bool allowDowncast = (mode > 0);
if (mode < 2)
collectLaneSizes(vn,lanedRegister,checkLanes);
else {
checkLanes.addLaneSize(4); // Default lane size
}
LanedRegister::const_iterator enditer = checkLanes.end();
for(LanedRegister::const_iterator iter=checkLanes.begin();iter!=enditer;++iter) {
int4 curSize = *iter;
LaneDescription description(lanedRegister.getWholeSize(),curSize); // Lane scheme dictated by curSize
LaneDivide laneDivide(&data,vn,description,allowDowncast);
if (laneDivide.doTrace()) {
laneDivide.apply();
count += 1; // Indicate a change was made
return true;
}
}
return false;
}
int4 ActionLaneDivide::apply(Funcdata &data)
{
map<VarnodeData,const LanedRegister *>::const_iterator iter;
for(int4 mode=0;mode<3;++mode) {
bool allStorageProcessed = true;
for(iter=data.beginLaneAccess();iter!=data.endLaneAccess();++iter) {
const LanedRegister *lanedReg = (*iter).second;
Address addr = (*iter).first.getAddr();
int4 sz = (*iter).first.size;
VarnodeLocSet::const_iterator viter = data.beginLoc(sz,addr);
VarnodeLocSet::const_iterator venditer = data.endLoc(sz,addr);
bool allVarnodesProcessed = true;
while(viter != venditer) {
Varnode *vn = *viter;
if (processVarnode(data, vn, *lanedReg, mode)) {
viter = data.beginLoc(sz,addr);
venditer = data.endLoc(sz, addr); // Recalculate bounds
allVarnodesProcessed = true;
}
else {
++viter;
allVarnodesProcessed = false;
}
}
if (!allVarnodesProcessed)
allStorageProcessed = false;
}
if (allStorageProcessed) break;
}
data.clearLanedAccessMap();
return 0;
}
int4 ActionSegmentize::apply(Funcdata &data)
{
int4 numops = data.getArch()->userops.numSegmentOps();
if (numops==0) return 0;
if (localcount>0) return 0; // Only perform once
localcount = 1; // Mark as having performed once
vector<Varnode *> bindlist;
bindlist.push_back((Varnode *)0);
bindlist.push_back((Varnode *)0);
for(int4 i=0;i<numops;++i) {
SegmentOp *segdef = data.getArch()->userops.getSegmentOp(i);
if (segdef == (SegmentOp *)0) continue;
AddrSpace *spc = segdef->getSpace();
list<PcodeOp *>::const_iterator iter,enditer;
iter = data.beginOp(CPUI_CALLOTHER);
enditer = data.endOp(CPUI_CALLOTHER);
int4 uindex = segdef->getIndex();
while(iter != enditer) {
PcodeOp *segroot = *iter++;
if (segroot->isDead()) continue;
if (segroot->getIn(0)->getOffset() != uindex) continue;
if (!segdef->unify(data,segroot,bindlist)) {
ostringstream err;
err << "Segment op in wrong form at ";
segroot->getAddr().printRaw(err);
throw LowlevelError(err.str());
}
if (segdef->getNumVariableTerms()==1)
bindlist[1] = data.newConstant(4,0);
// Redefine the op as a segmentop
data.opSetOpcode(segroot,CPUI_SEGMENTOP);
data.opSetInput(segroot,data.newVarnodeSpace(spc),0);
data.opSetInput(segroot,bindlist[1],1);
data.opSetInput(segroot,bindlist[0],2);
for(int4 j=segroot->numInput()-1;j>2;--j) // Remove anything else
data.opRemoveInput(segroot,j);
count += 1;
}
}
return 0;
}
int4 ActionForceGoto::apply(Funcdata &data)
{
data.getOverride().applyForceGoto(data);
return 0;
}
int4 ActionConstbase::apply(Funcdata &data)
{
if (data.getBasicBlocks().getSize()==0) return 0; // No blocks
// Get start block, which is constructed to have nothing
// falling into it
BlockBasic *bb = (BlockBasic *)data.getBasicBlocks().getBlock(0);
int4 injectid = data.getFuncProto().getInjectUponEntry();
if (injectid >= 0) {
InjectPayload *payload = data.getArch()->pcodeinjectlib->getPayload(injectid);
data.doLiveInject(payload,bb->getStart(),bb,bb->beginOp());
}
const TrackedSet trackset( data.getArch()->context->getTrackedSet(data.getAddress()));
for(int4 i=0;i<trackset.size();++i) {
const TrackedContext &ctx(trackset[i]);
Address addr(ctx.loc.space,ctx.loc.offset);
PcodeOp *op = data.newOp(1,bb->getStart());
data.newVarnodeOut(ctx.loc.size,addr,op);
Varnode *vnin = data.newConstant(ctx.loc.size,ctx.val);
data.opSetOpcode(op,CPUI_COPY);
data.opSetInput(op,vnin,0);
data.opInsertBegin(op,bb);
}
return 0;
}
// int4 ActionCse::apply(Funcdata &data)
// {
// vector< pair<uintm,PcodeOp *> > list;
// vector<Varnode *> vlist;
// PcodeOp *op;
// list<PcodeOp *>::const_iterator iter;
// uintm hash;
// for(iter=data.op_alive_begin();iter!=data.op_alive_end();++iter) {
// op = *iter;
// hash = op->getCseHash();
// if (hash == 0) continue;
// list.push_back(pair<uintm,PcodeOp *>(hash,op));
// }
// if (list.empty()) return 0;
// cseEliminateList(data,list,vlist);
// while(!vlist.empty()) {
// count += 1; // Indicate that changes have been made
// list.clear();
// cse_build_fromvarnode(list,vlist);
// vlist.clear();
// cseEliminateList(data,list,vlist);
// }
// return 0;
// }
/// We are substituting either -out1- for -out2- OR -out2- for -out1-
/// Return true if we prefer substituting -out2- for -out1-
/// \param out1 is one output
/// \param out2 is the other output
/// \return preference
bool ActionMultiCse::preferredOutput(Varnode *out1,Varnode *out2)
{
// Prefer the output that is used in a CPUI_RETURN
list<PcodeOp *>::const_iterator iter,enditer;
enditer = out1->endDescend();
for(iter=out1->beginDescend();iter!=enditer;++iter) {
PcodeOp *op = *iter;
if (op->code() == CPUI_RETURN)
return false;
}
enditer = out2->endDescend();
for(iter=out2->beginDescend();iter!=enditer;++iter) {
PcodeOp *op = *iter;
if (op->code() == CPUI_RETURN)
return true;
}
// Prefer addrtied over register over unique
if (!out1->isAddrTied()) {
if (out2->isAddrTied())
return true;
else {
if (out1->getSpace()->getType()==IPTR_INTERNAL) {
if (out2->getSpace()->getType()!=IPTR_INTERNAL)
return true;
}
}
}
return false;
}
/// Find any matching CPUI_MULTIEQUAL that occurs before \b target that has \b in as an input.
/// Then test to see if the \b target and the recovered op are functionally equivalent.
/// \param bl is the parent block
/// \param target is the given target CPUI_MULTIEQUAL
/// \param in is the specific input Varnode
PcodeOp *ActionMultiCse::findMatch(BlockBasic *bl,PcodeOp *target,Varnode *in)
{
list<PcodeOp *>::iterator iter = bl->beginOp();
for(;;) {
PcodeOp *op = *iter;
++iter;
if (op == target) // Caught up with target, nothing else before it
break;
int4 i,numinput;
numinput = op->numInput();
for(i=0;i<numinput;++i) {
Varnode *vn = op->getIn(i);
if (vn->isWritten() && (vn->getDef()->code() == CPUI_COPY))
vn = vn->getDef()->getIn(0); // Allow for differences in copy propagation
if (vn == in) break;
}
if (i < numinput) {
int4 j;
Varnode *buf1[2];
Varnode *buf2[2];
for(j=0;j<numinput;++j) {
Varnode *in1 = op->getIn(j);
if (in1->isWritten() && (in1->getDef()->code() == CPUI_COPY))
in1 = in1->getDef()->getIn(0); // Allow for differences in copy propagation
Varnode *in2 = target->getIn(j);
if (in2->isWritten() && (in2->getDef()->code() == CPUI_COPY))
in2 = in2->getDef()->getIn(0);
if (in1 == in2) continue;
if (0!=functionalEqualityLevel(in1,in2,buf1,buf2))
break;
}
if (j==numinput) // We have found a redundancy
return op;
}
}
return (PcodeOp *)0;
}
/// Search for pairs of CPUI_MULTIEQUAL ops in \b bl that share an input.
/// If the pairs found are functionally equivalent, delete one of the two.
/// \param data is the function owning the block
/// \param bl is the specific basic block
/// return \b true if a CPUI_MULTIEQUAL was (successfully) deleted
bool ActionMultiCse::processBlock(Funcdata &data,BlockBasic *bl)
{
vector<Varnode *> vnlist;
PcodeOp *targetop = (PcodeOp *)0;
PcodeOp *pairop;
list<PcodeOp *>::iterator iter = bl->beginOp();
list<PcodeOp *>::iterator enditer = bl->endOp();
while(iter != enditer) {
PcodeOp *op = *iter;
++iter;
OpCode opc = op->code();
if (opc == CPUI_COPY) continue;
if (opc != CPUI_MULTIEQUAL) break;
int4 vnpos = vnlist.size();
int4 i;
int4 numinput = op->numInput();
for(i=0;i<numinput;++i) {
Varnode *vn = op->getIn(i);
if (vn->isWritten() && (vn->getDef()->code() == CPUI_COPY)) // Some copies may not propagate into MULTIEQUAL
vn = vn->getDef()->getIn(0); // Allow for differences in copy propagation
vnlist.push_back(vn);
if (vn->isMark()) { // If we've seen this varnode before
pairop = findMatch(bl,op,vn);
if (pairop != (PcodeOp *)0)
break;
}
}
if (i<numinput) {
targetop = op;
break;
}
for(i=vnpos;i<vnlist.size();++i)
vnlist[i]->setMark(); // Mark that we have seen this varnode
}
// Clear out any of the marks we put down
for(int4 i=0;i<vnlist.size();++i)
vnlist[i]->clearMark();
if (targetop != (PcodeOp *)0) {
Varnode *out1 = pairop->getOut();
Varnode *out2 = targetop->getOut();
if (preferredOutput(out1,out2)) {
data.totalReplace(out1,out2); // Replace pairop and out1 in favor of targetop and out2
data.opDestroy(pairop);
}
else {
data.totalReplace(out2,out1);
data.opDestroy(targetop);
}
count += 1; // Indicate that a change has taken place
return true;
}
return false;
}
int4 ActionMultiCse::apply(Funcdata &data)
{
const BlockGraph &bblocks( data.getBasicBlocks() );
int4 sz = bblocks.getSize();
for(int4 i=0;i<sz;++i) {
BlockBasic *bl = (BlockBasic *)bblocks.getBlock(i);
while(processBlock(data,bl)) {
}
}
return 0;
}
int4 ActionShadowVar::apply(Funcdata &data)
{
const BlockGraph &bblocks(data.getBasicBlocks());
BlockBasic *bl;
PcodeOp *op;
Varnode *vn;
vector<Varnode *> vnlist;
list<PcodeOp *> oplist;
uintb startoffset;
for(int4 i=0;i<bblocks.getSize();++i) {
vnlist.clear();
bl = (BlockBasic *)bblocks.getBlock(i);
// Iterator over all MULTIEQUALs in the block
// We have to check all ops in the first address
// We cannot stop at first non-MULTIEQUAL because
// other ops creep in because of multi_collapse
startoffset = bl->getStart().getOffset();
list<PcodeOp *>::iterator iter = bl->beginOp();
while(iter != bl->endOp()) {
op = *iter++;
if (op->getAddr().getOffset() != startoffset) break;
if (op->code() != CPUI_MULTIEQUAL) continue;
vn = op->getIn(0);
if (vn->isMark())
oplist.push_back(op);
else {
vn->setMark();
vnlist.push_back(vn);
}
}
for(int4 j=0;j<vnlist.size();++j)
vnlist[j]->clearMark();
}
list<PcodeOp *>::iterator oiter;
for(oiter=oplist.begin();oiter!=oplist.end();++oiter) {
op = *oiter;
PcodeOp *op2;
for(op2=op->previousOp();op2!=(PcodeOp *)0;op2=op2->previousOp()) {
if (op2->code() != CPUI_MULTIEQUAL) continue;
int4 i;
for(i=0;i<op->numInput();++i) // Check for match in each branch
if (op->getIn(i) != op2->getIn(i)) break;
if (i != op->numInput()) continue; // All branches did not match
vector<Varnode *> plist;
plist.push_back(op2->getOut());
data.opSetOpcode(op,CPUI_COPY);
data.opSetAllInput(op,plist);
count += 1;
}
}
return 0;
}
/// \brief Determine if given Varnode might be a pointer constant.
///
/// If it is a pointer, return the symbol it points to, or NULL otherwise. If it is determined
/// that the Varnode is a pointer to a specific symbol, the encoding of the full pointer is passed back.
/// Usually this is just the constant value of the Varnode, but in this case of partial pointers
/// (like \e near pointers) the full pointer may contain additional information.
/// \param spc is the address space being pointed to
/// \param vn is the given Varnode
/// \param op is the lone descendant of the Varnode
/// \param slot is the slot index of the Varnode
/// \param rampoint will hold the Address of the resolved symbol
/// \param fullEncoding will hold the full pointer encoding being passed back
/// \param data is the function being analyzed
/// \return the recovered symbol or NULL
SymbolEntry *ActionConstantPtr::isPointer(AddrSpace *spc,Varnode *vn,PcodeOp *op,int4 slot,
Address &rampoint,uintb &fullEncoding,Funcdata &data)
{
bool needexacthit;
Architecture *glb = data.getArch();
Varnode *outvn;
if (vn->getType()->getMetatype() == TYPE_PTR) { // Are we explicitly marked as a pointer
rampoint = glb->resolveConstant(spc,vn->getOffset(),vn->getSize(),op->getAddr(),fullEncoding);
needexacthit = false;
}
else {
if (vn->isTypeLock()) return (SymbolEntry *)0; // Locked as NOT a pointer
needexacthit = true;
// Check if the constant is involved in a potential pointer expression
// as the base
switch(op->code()) {
case CPUI_RETURN:
case CPUI_CALL:
case CPUI_CALLIND:
// A constant parameter or return value could be a pointer
if (!glb->infer_pointers)
return (SymbolEntry *)0;
if (slot==0)
return (SymbolEntry *)0;
break;
case CPUI_COPY:
case CPUI_INT_EQUAL:
case CPUI_INT_NOTEQUAL:
case CPUI_INT_LESS:
case CPUI_INT_LESSEQUAL:
// A comparison with a constant could be a pointer
break;
case CPUI_INT_ADD:
outvn = op->getOut();
if (outvn->getType()->getMetatype()==TYPE_PTR) {
// Is there another pointer base in this expression
if (op->getIn(1-slot)->getType()->getMetatype()==TYPE_PTR)
return (SymbolEntry *)0; // If so, we are not a pointer
// FIXME: need to fully explore additive tree
needexacthit = false;
}
else if (!glb->infer_pointers)
return (SymbolEntry *)0;
break;
case CPUI_STORE:
if (slot != 2)
return (SymbolEntry *)0;
break;
default: