1. Add an architecture-independent interface to check whether a regis…

…ter represents a flag 2. In jump table analysis, perform shift-left operations if both operands are constant and use architecture-independent interface
dyninst · Oct 4, 2016 · 3a8715b · 3a8715b
1 parent 010df64
commit 3a8715b
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Showing 6 changed files with 44 additions and 10 deletions.
diff --git a/common/h/dyn_regs.h b/common/h/dyn_regs.h
@@ -106,6 +106,7 @@ namespace Dyninst
         bool isStackPointer() const;
         bool isSyscallNumberReg() const;
         bool isSyscallReturnValueReg() const;
+	bool isFlag() const;
 
         void getROSERegister(int &c, int &n, int &p);
 

diff --git a/common/src/dyn_regs.C b/common/src/dyn_regs.C
@@ -478,6 +478,23 @@ bool MachRegister::isSyscallReturnValueReg() const
             );
 }
 
+bool MachRegister::isFlag() const
+{
+    int regC = regClass();
+    switch (getArchitecture())
+    {
+      case Arch_x86:
+         return regC == x86::FLAG;
+      case Arch_x86_64:
+         return regC == x86_64::FLAG;
+      case Arch_aarch64:
+         return regC == aarch64::FLAG;
+      default:
+         assert(!"Not implemented!");
+   }
+   return false;
+}
+
 COMMON_EXPORT bool Dyninst::isSegmentRegister(int regClass)
 {
    return 0 != (regClass & x86::SEG);

diff --git a/parseAPI/src/BoundFactCalculator.C b/parseAPI/src/BoundFactCalculator.C
@@ -320,6 +320,7 @@ static bool IsConditionalJump(Instruction::Ptr insn) {
 	id == e_jb_jnaej_j || id == e_jnb_jae_j ||
 	id == e_jle || id == e_jl ||
 	id == e_jnl || id == e_jnle) return true;
+    if (id == aarch64_op_b_cond) return true;
     return false;
 }
 

diff --git a/parseAPI/src/BoundFactData.C b/parseAPI/src/BoundFactData.C
@@ -1146,6 +1146,7 @@ bool BoundFact::ConditionalJumpBound(Instruction::Ptr insn, EdgeTypeEnum type) {
 		}
 		break;
 	    }
+	    case aarch64_op_b_cond:
 	    case e_jnbe: {
 	        if (pred.e1->getID() == AST::V_ConstantAST) {
 		    if (pred.e2->getID() == AST::V_ConstantAST) {
@@ -1315,14 +1316,19 @@ void BoundFact::SetPredicate(Assignment::Ptr assign,std::pair<AST::Ptr, bool> ex
     }
     AST::Ptr simplifiedAST = expandRet.first;
     parsing_printf("\t\t semanic expansions: %s\n", simplifiedAST->format().c_str());
+
+    ComparisonVisitor cv;
+    expandRet.first->accept(&cv);
+    pred.e1 = cv.subtrahend;
+    pred.e2 = cv.minuend; 
+    pred.id = id;
+    if (pred.e1 != AST::Ptr() && pred.e2 != AST::Ptr()) {
+        return;
+    }
+
     switch (id) {
         case e_cmp:
 	case e_sub: {	
-	    ComparisonVisitor cv;
-	    expandRet.first->accept(&cv);
-	    pred.e1 = cv.subtrahend;
-	    pred.e2 = cv.minuend; 
-	    pred.id = id;
 	    // The effect of the subtraction can only
 	    // be evaluated when there is a conditional jump
 	    // after it. Currently, we do not know anything.

diff --git a/parseAPI/src/IndirectASTVisitor.C b/parseAPI/src/IndirectASTVisitor.C
@@ -113,6 +113,14 @@ AST::Ptr SimplifyRoot(AST::Ptr ast, uint64_t insnSize) {
 		else
 		    return RoseAST::create(ROSEOperation(ROSEOperation::derefOp), ast->child(0));
 		break;
+	    case ROSEOperation::shiftLOp:
+	        if (roseAST->child(0)->getID() == AST::V_ConstantAST && roseAST->child(1)->getID() == AST::V_ConstantAST) {
+		    ConstantAST::Ptr child0 = boost::static_pointer_cast<ConstantAST>(roseAST->child(0));
+		    ConstantAST::Ptr child1 = boost::static_pointer_cast<ConstantAST>(roseAST->child(1));
+		    return ConstantAST::create(Constant(child0->val().val << child1->val().val, 64));
+		}
+		break;
+
 	    default:
 	        break;
 

diff --git a/parseAPI/src/JumpTablePred.C b/parseAPI/src/JumpTablePred.C
@@ -91,7 +91,7 @@ static void BuildEdges(SliceNode::Ptr curNode,
 
 static bool AssignIsZF(Assignment::Ptr a) {
     return a->out().absloc().type() == Absloc::Register &&
-	   (a->out().absloc().reg() == x86::zf || a->out().absloc().reg() == x86_64::zf);
+	   (a->out().absloc().reg() == MachRegister::getZeroFlag(a->out().absloc().reg().getArchitecture()));
 }
 
 static bool IsPushAndChangeSP(Assignment::Ptr a) {
@@ -184,11 +184,12 @@ bool JumpTablePred::addNodeCallback(AssignmentPtr ap, set<ParseAPI::Edge*> &visi
     if (currentAssigns.find(ap) != currentAssigns.end()) return true;
     if (currentAssigns.size() > 50) return false; 
     // For flags, we only analyze zf
-    if (ap->out().absloc().type() == Absloc::Register && ap->out().absloc().reg().regClass() == (unsigned int)x86::FLAG &&
-       ap->out().absloc().reg() != x86::zf && ap->out().absloc().reg() != x86_64::zf) {
-	return true;
+    if (ap->out().absloc().type() == Absloc::Register) {
+        MachRegister reg = ap->out().absloc().reg();
+	if (reg.isFlag() && reg != MachRegister::getZeroFlag(reg.getArchitecture())) {
+	    return true;
+	}
     }
-
     pair<AST::Ptr, bool> expandRet = ExpandAssignment(ap);
 
     currentAssigns.insert(ap);