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https://github.com/NationalSecurityAgency/ghidra.git
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Candidate release of source code.
This commit is contained in:
parent
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79d8f164f8
12449 changed files with 2800756 additions and 16 deletions
375
Ghidra/Features/Decompiler/src/decompile/cpp/cast.cc
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375
Ghidra/Features/Decompiler/src/decompile/cpp/cast.cc
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/* ###
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* IP: GHIDRA
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "cast.hh"
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#include "op.hh"
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/// Sets the TypeFactory used to produce data-types for the arithmeticOutputStandard() method
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/// \param t is the TypeFactory
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void CastStrategy::setTypeFactory(TypeFactory *t)
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{
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tlst = t;
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promoteSize = tlst->getSizeOfInt();
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}
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bool CastStrategyC::checkIntPromotionForCompare(const PcodeOp *op,int4 slot) const
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{
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const Varnode *vn = op->getIn(slot);
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int4 exttype1 = intPromotionType(vn);
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if (exttype1 == NO_PROMOTION) return false;
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if (exttype1 == UNKNOWN_PROMOTION) return true; // If there is promotion and we don't know type, we need a cast
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int4 exttype2 = intPromotionType(op->getIn(1-slot));
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if ((exttype1 & exttype2) != 0) // If both sides share a common extension, then these bits aren't determining factor
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return false;
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if (exttype2 == NO_PROMOTION) {
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// other side would not have integer promotion, but our side is forcing it
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// but both sides get extended in the same way
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return false;
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}
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return true;
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}
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bool CastStrategyC::checkIntPromotionForExtension(const PcodeOp *op) const
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{
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const Varnode *vn = op->getIn(0);
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int4 exttype = intPromotionType(vn);
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if (exttype == NO_PROMOTION) return false;
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if (exttype == UNKNOWN_PROMOTION) return true; // If there is an extension and we don't know type, we need a cast
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// Test if the promotion extension matches the explicit extension
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if (((exttype & UNSIGNED_EXTENSION) != 0) && (op->code() == CPUI_INT_ZEXT)) return false;
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if (((exttype & SIGNED_EXTENSION) != 0) && (op->code() == CPUI_INT_SEXT)) return false;
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return true; // Otherwise we need a cast before we extend
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}
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int4 CastStrategyC::localExtensionType(const Varnode *vn) const
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{
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type_metatype meta = vn->getHigh()->getType()->getMetatype();
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int4 natural; // 1= natural zero extension, 2= natural sign extension
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if ((meta == TYPE_UINT)||(meta == TYPE_BOOL)||(meta == TYPE_UNKNOWN))
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natural = UNSIGNED_EXTENSION;
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else if (meta == TYPE_INT)
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natural = SIGNED_EXTENSION;
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else
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return UNKNOWN_PROMOTION;
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if (vn->isConstant()) {
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if (!signbit_negative(vn->getOffset(),vn->getSize())) // If the high-bit is zero
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return EITHER_EXTENSION; // Can be viewed as either extension
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return natural;
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}
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if (vn->isExplicit())
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return natural;
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if (!vn->isWritten())
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return UNKNOWN_PROMOTION;
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const PcodeOp *op = vn->getDef();
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if (op->isBoolOutput())
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return EITHER_EXTENSION;
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OpCode opc = op->code();
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if ((opc == CPUI_CAST)||(opc == CPUI_LOAD)||op->isCall())
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return natural;
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if (opc == CPUI_INT_AND) { // This is kind of recursing
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const Varnode *tmpvn = op->getIn(1);
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if (tmpvn->isConstant()) {
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if (!signbit_negative(tmpvn->getOffset(),tmpvn->getSize()))
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return EITHER_EXTENSION;
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return natural;
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}
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}
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return UNKNOWN_PROMOTION;
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}
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int4 CastStrategyC::intPromotionType(const Varnode *vn) const
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{
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int4 val;
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if (vn->getSize() >= promoteSize)
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return NO_PROMOTION;
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if (vn->isConstant())
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return localExtensionType(vn);
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if (vn->isExplicit())
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return NO_PROMOTION;
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if (!vn->isWritten()) return UNKNOWN_PROMOTION;
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const PcodeOp *op = vn->getDef();
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const Varnode *othervn;
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switch(op->code()) {
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case CPUI_INT_AND:
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othervn = op->getIn(1);
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if ((localExtensionType(othervn) & UNSIGNED_EXTENSION) != 0)
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return UNSIGNED_EXTENSION;
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othervn = op->getIn(0);
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if ((localExtensionType(othervn) & UNSIGNED_EXTENSION) != 0)
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return UNSIGNED_EXTENSION; // If either side has zero extension, result has zero extension
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break;
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case CPUI_INT_RIGHT:
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othervn = op->getIn(0);
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val = localExtensionType(othervn);
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if ((val & UNSIGNED_EXTENSION) != 0) // If the input provably zero extends
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return val; // then the result is a zero extension (plus possibly a sign extension)
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break;
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case CPUI_INT_SRIGHT:
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othervn = op->getIn(0);
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val = localExtensionType(othervn);
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if ((val & SIGNED_EXTENSION) != 0) // If input can be construed as a sign-extension
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return val; // then the result is a sign extension (plus possibly a zero extension)
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break;
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case CPUI_INT_XOR:
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case CPUI_INT_OR:
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case CPUI_INT_DIV:
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case CPUI_INT_REM:
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othervn = op->getIn(0);
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if ((localExtensionType(othervn) & UNSIGNED_EXTENSION) == 0)
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return UNKNOWN_PROMOTION;
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othervn = op->getIn(1);
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if ((localExtensionType(othervn) & UNSIGNED_EXTENSION) == 0)
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return UNKNOWN_PROMOTION;
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return UNSIGNED_EXTENSION; // If both sides have zero extension, result has zero extension
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case CPUI_INT_SDIV:
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case CPUI_INT_SREM:
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othervn = op->getIn(0);
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if ((localExtensionType(othervn) & SIGNED_EXTENSION) == 0)
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return UNKNOWN_PROMOTION;
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othervn = op->getIn(1);
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if ((localExtensionType(othervn) & SIGNED_EXTENSION) == 0)
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return UNKNOWN_PROMOTION;
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return SIGNED_EXTENSION; // If both sides have sign extension, result has sign extension
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case CPUI_INT_NEGATE:
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case CPUI_INT_2COMP:
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othervn = op->getIn(0);
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if ((localExtensionType(othervn) & SIGNED_EXTENSION) != 0)
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return SIGNED_EXTENSION;
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break;
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case CPUI_INT_ADD:
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case CPUI_INT_SUB:
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case CPUI_INT_LEFT:
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case CPUI_INT_MULT:
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break;
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default:
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return NO_PROMOTION; // No integer promotion at all
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}
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return UNKNOWN_PROMOTION;
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}
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Datatype *CastStrategyC::castStandard(Datatype *reqtype,Datatype *curtype,
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bool care_uint_int,bool care_ptr_uint) const
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{ // Generic casting rules that apply for most ops
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if (curtype == reqtype) return (Datatype *)0; // Types are equal, no cast required
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Datatype *reqbase = reqtype;
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Datatype *curbase = curtype;
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bool isptr = false;
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while((reqbase->getMetatype()==TYPE_PTR)&&(curbase->getMetatype()==TYPE_PTR)) {
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reqbase = ((const TypePointer *)reqbase)->getPtrTo();
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curbase = ((const TypePointer *)curbase)->getPtrTo();
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care_uint_int = true;
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isptr = true;
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}
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if (curtype == reqtype) return (Datatype *)0; // Different typedefs could point to the same type
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if ((reqbase->getMetatype()==TYPE_VOID)||(reqbase->getMetatype()==TYPE_VOID))
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return (Datatype *)0; // Don't cast from or to VOID
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if (reqbase->getSize() != curbase->getSize()) return reqtype; // Always cast change in size
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switch(reqbase->getMetatype()) {
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case TYPE_UNKNOWN:
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return (Datatype *)0;
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case TYPE_UINT:
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if (!care_uint_int) {
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type_metatype meta = curbase->getMetatype();
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// Note: meta can be TYPE_UINT if curbase is typedef/enumerated
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if ((meta==TYPE_UNKNOWN)||(meta==TYPE_INT)||(meta==TYPE_UINT)||(meta==TYPE_BOOL))
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return (Datatype *)0;
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}
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else {
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type_metatype meta = curbase->getMetatype();
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if ((meta == TYPE_UINT)||(meta==TYPE_BOOL)) // Can be TYPE_UINT for typedef/enumerated
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return (Datatype *)0;
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if (isptr && (meta==TYPE_UNKNOWN)) // Don't cast pointers to unknown
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return (Datatype *)0;
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}
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if ((!care_ptr_uint)&&(curbase->getMetatype()==TYPE_PTR))
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return (Datatype *)0;
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break;
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case TYPE_INT:
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if (!care_uint_int) {
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type_metatype meta = curbase->getMetatype();
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// Note: meta can be TYPE_INT if curbase is an enumerated type
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if ((meta==TYPE_UNKNOWN)||(meta==TYPE_INT)||(meta==TYPE_UINT)||(meta==TYPE_BOOL))
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return (Datatype *)0;
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}
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else {
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type_metatype meta = curbase->getMetatype();
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if ((meta == TYPE_INT)||(meta == TYPE_BOOL))
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return (Datatype *)0; // Can be TYPE_INT for typedef/enumerated/char
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if (isptr && (meta==TYPE_UNKNOWN)) // Don't cast pointers to unknown
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return (Datatype *)0;
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}
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break;
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case TYPE_CODE:
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if (curbase->getMetatype() == TYPE_CODE) {
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// Don't cast between function pointer and generic code pointer
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if (((TypeCode *)reqbase)->getPrototype() == (const FuncProto *)0)
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return (Datatype *)0;
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if (((TypeCode *)curbase)->getPrototype() == (const FuncProto *)0)
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return (Datatype *)0;
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}
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break;
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default:
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break;
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}
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return reqtype;
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}
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Datatype *CastStrategyC::arithmeticOutputStandard(const PcodeOp *op)
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{
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Datatype *res1 = op->getIn(0)->getHigh()->getType();
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if (res1->getMetatype() == TYPE_BOOL) // Treat boolean as if it is cast to an integer
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res1 = tlst->getBase(res1->getSize(),TYPE_INT);
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Datatype *res2;
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for(int4 i=1;i<op->numInput();++i) {
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res2 = op->getIn(i)->getHigh()->getType();
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if (res2->getMetatype() == TYPE_BOOL) continue;
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if (0>res2->typeOrder(*res1))
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res1 = res2;
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}
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return res1;
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}
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bool CastStrategyC::isSubpieceCast(Datatype *outtype,Datatype *intype,uint4 offset) const
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{
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if (offset != 0) return false;
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type_metatype inmeta = intype->getMetatype();
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if ((inmeta!=TYPE_INT)&&
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(inmeta!=TYPE_UINT)&&
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(inmeta!=TYPE_UNKNOWN)&&
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(inmeta!=TYPE_PTR))
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return false;
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type_metatype outmeta = outtype->getMetatype();
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if ((outmeta!=TYPE_INT)&&
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(outmeta!=TYPE_UINT)&&
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(outmeta!=TYPE_UNKNOWN)&&
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(outmeta!=TYPE_PTR)&&
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(outmeta!=TYPE_FLOAT))
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return false;
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if ((inmeta==TYPE_PTR)&&((outmeta!=TYPE_INT) && (outmeta!=TYPE_UINT)))
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return false; //other casts don't make sense for pointers
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return true;
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}
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bool CastStrategyC::isSubpieceCastEndian(Datatype *outtype,Datatype *intype,uint4 offset,bool isbigend) const
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{
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uint4 tmpoff = offset;
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if (isbigend)
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tmpoff = intype->getSize()-1-offset;
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return isSubpieceCast(outtype,intype,tmpoff);
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}
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bool CastStrategyC::isSextCast(Datatype *outtype,Datatype *intype) const
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{
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if (outtype->getMetatype()!=TYPE_INT) return false;
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type_metatype metain = intype->getMetatype();
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if ((metain!=TYPE_INT)&&(metain!=TYPE_UINT)&&(metain!=TYPE_BOOL))
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return false;
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return true;
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}
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bool CastStrategyC::isZextCast(Datatype *outtype,Datatype *intype) const
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{
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if (outtype->getMetatype()!=TYPE_UINT) return false;
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type_metatype metain = intype->getMetatype();
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if ((metain!=TYPE_INT)&&(metain!=TYPE_UINT)&&(metain!=TYPE_BOOL))
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return false;
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return true;
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}
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Datatype *CastStrategyJava::castStandard(Datatype *reqtype,Datatype *curtype,
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bool care_uint_int,bool care_ptr_uint) const
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{
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if (curtype == reqtype) return (Datatype *)0; // Types are equal, no cast required
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Datatype *reqbase = reqtype;
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Datatype *curbase = curtype;
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if ((reqbase->getMetatype()==TYPE_PTR)||(curbase->getMetatype()==TYPE_PTR))
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return (Datatype *)0; // There must be explicit cast op between objects, so assume no cast necessary
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if ((reqbase->getMetatype()==TYPE_VOID)||(reqbase->getMetatype()==TYPE_VOID))
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return (Datatype *)0; // Don't cast from or to VOID
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if (reqbase->getSize() != curbase->getSize()) return reqtype; // Always cast change in size
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switch(reqbase->getMetatype()) {
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case TYPE_UNKNOWN:
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return (Datatype *)0;
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case TYPE_UINT:
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if (!care_uint_int) {
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type_metatype meta = curbase->getMetatype();
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// Note: meta can be TYPE_UINT if curbase is typedef/enumerated
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if ((meta==TYPE_UNKNOWN)||(meta==TYPE_INT)||(meta==TYPE_UINT)||(meta==TYPE_BOOL))
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return (Datatype *)0;
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}
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else {
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type_metatype meta = curbase->getMetatype();
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if ((meta == TYPE_UINT)||(meta==TYPE_BOOL)) // Can be TYPE_UINT for typedef/enumerated
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return (Datatype *)0;
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}
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break;
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case TYPE_INT:
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if (!care_uint_int) {
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type_metatype meta = curbase->getMetatype();
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// Note: meta can be TYPE_INT if curbase is an enumerated type
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if ((meta==TYPE_UNKNOWN)||(meta==TYPE_INT)||(meta==TYPE_UINT)||(meta==TYPE_BOOL))
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return (Datatype *)0;
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}
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else {
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type_metatype meta = curbase->getMetatype();
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if ((meta == TYPE_INT)||(meta == TYPE_BOOL))
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return (Datatype *)0; // Can be TYPE_INT for typedef/enumerated/char
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}
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break;
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case TYPE_CODE:
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if (curbase->getMetatype() == TYPE_CODE) {
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// Don't cast between function pointer and generic code pointer
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if (((TypeCode *)reqbase)->getPrototype() == (const FuncProto *)0)
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return (Datatype *)0;
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if (((TypeCode *)curbase)->getPrototype() == (const FuncProto *)0)
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return (Datatype *)0;
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}
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break;
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default:
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break;
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}
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return reqtype;
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}
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bool CastStrategyJava::isZextCast(Datatype *outtype,Datatype *intype) const
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{
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type_metatype outmeta = outtype->getMetatype();
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if ((outmeta!=TYPE_INT)&&(outmeta!=TYPE_UINT)&&(outmeta!=TYPE_BOOL)) return false;
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type_metatype inmeta = intype->getMetatype();
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if ((inmeta!=TYPE_INT)&&(inmeta!=TYPE_UINT)&&(inmeta!=TYPE_BOOL)) return false; // Non-integer types, print functional ZEXT
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if ((intype->getSize() == 2)&&(!intype->isCharPrint())) return false; // cast is not zext for short
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if ((intype->getSize()==1)&&(inmeta==TYPE_INT)) return false; // cast is not zext for byte
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if (intype->getSize()>=4) return false; // cast is not zext for int and long
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return true;
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}
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