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Code Issues Releases Wiki Activity

Hide implied extensions for arithmetic ops

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This commit is contained in:
caheckman 2019-05-09 17:35:57 -04:00
parent 706960a139
commit 8860979785
6 changed files with 139 additions and 56 deletions
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52
Ghidra/Features/Decompiler/src/decompile/cpp/printc.cc
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@ -18,6 +18,7 @@
// Operator tokens for expressions
// token #in prec assoc optype space bump
OpToken PrintC::hidden = { "", 1, 70, false, OpToken::hiddenfunction, 0, 0, (OpToken *)0 };
OpToken PrintC::scope = { "::", 2, 70, true, OpToken::binary, 0, 0, (OpToken *)0 };
OpToken PrintC::object_member = { ".", 2, 66, true, OpToken::binary, 0, 0, (OpToken *)0 };
OpToken PrintC::pointer_member = { "->", 2, 66, true, OpToken::binary, 0, 0, (OpToken *)0 };
@ -98,6 +99,7 @@ PrintC::PrintC(Architecture *g,const string &nm) : PrintLanguage(g,nm)
option_convention = true;
option_nocasts = false;
option_unplaced = false;
option_hide_exts = true;
nullToken = "NULL";
// Set the flip tokens
@ -319,6 +321,21 @@ void PrintC::opTypeCast(const PcodeOp *op)
pushVnImplied(op->getIn(0),op,mods);
}
/// The syntax represents the given op using a function with one input,
/// where the function name is not printed. The input expression is simply printed
/// without adornment inside the larger expression, with one minor difference.
/// The hidden operator protects against confusing evaluation order between
/// the operators inside and outside the hidden function. If both the inside
/// and outside operators are the same associative token, the hidden token
/// makes sure the inner expression is surrounded with parentheses.
/// \param op is the given PcodeOp
void PrintC::opHiddenFunc(const PcodeOp *op)
{
pushOp(&hidden,op);
pushVnImplied(op->getIn(0),op,mods);
}
void PrintC::opCopy(const PcodeOp *op)
{
@ -579,7 +596,7 @@ void PrintC::opIntZext(const PcodeOp *op)
{
if (castStrategy->isZextCast(op->getOut()->getHigh()->getType(),op->getIn(0)->getHigh()->getType())) {
if (isExtensionCastImplied(op))
pushVnImplied(op->getIn(0),op,mods);
opHiddenFunc(op);
else
opTypeCast(op);
}
@ -592,7 +609,7 @@ void PrintC::opIntSext(const PcodeOp *op)
{
if (castStrategy->isSextCast(op->getOut()->getHigh()->getType(),op->getIn(0)->getHigh()->getType())) {
if (isExtensionCastImplied(op))
pushVnImplied(op->getIn(0),op,mods);
opHiddenFunc(op);
else
opTypeCast(op);
}
@ -1265,6 +1282,8 @@ bool PrintC::printCharacterConstant(ostream &s,const Address &addr,int4 charsize
bool PrintC::isExtensionCastImplied(const PcodeOp *op) const
{
if (!option_hide_exts)
return false; // If hiding extensions is not on, we must always print extension
const Varnode *outVn = op->getOut();
if (outVn->isExplicit()) {
@ -1272,9 +1291,32 @@ bool PrintC::isExtensionCastImplied(const PcodeOp *op) const
else {
PcodeOp *expOp = outVn->loneDescend();
if (expOp != (PcodeOp *)0) {
OpCode opc = expOp->code();
if (opc == CPUI_PTRADD)
return true;
type_metatype metatype = outVn->getHigh()->getType()->getMetatype();
Varnode *otherVn;
int4 slot;
switch(expOp->code()) {
case CPUI_PTRADD:
return true;
case CPUI_INT_ADD:
case CPUI_INT_SUB:
case CPUI_INT_MULT:
case CPUI_INT_DIV:
case CPUI_INT_AND:
case CPUI_INT_OR:
case CPUI_INT_XOR:
case CPUI_INT_LESS:
case CPUI_INT_LESSEQUAL:
case CPUI_INT_SLESS:
case CPUI_INT_SLESSEQUAL:
slot = expOp->getSlot(outVn);
otherVn = expOp->getIn(1-slot);
// Check if the expression involves an explicit variable of the right integer type
if (otherVn->isExplicit() && otherVn->getHigh()->getType()->getMetatype() == metatype)
return true;
break;
default:
break;
}
}
}
return false;