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package io.joern.c2cpg.astcreation
import io.shiftleft.codepropertygraph.generated.DispatchTypes
import io.shiftleft.codepropertygraph.generated.nodes.{
AstNodeNew,
ExpressionNew,
NewBlock,
NewCall,
NewFieldIdentifier,
NewNode
}
import io.joern.x2cpg.{Ast, AstEdge, ValidationMode}
import io.shiftleft.codepropertygraph.generated.nodes.NewLocal
import org.apache.commons.lang3.StringUtils
import org.eclipse.cdt.core.dom.ast.{IASTMacroExpansionLocation, IASTNode, IASTPreprocessorMacroDefinition}
import org.eclipse.cdt.core.dom.ast.IASTBinaryExpression
import org.eclipse.cdt.internal.core.model.ASTStringUtil
import scala.annotation.nowarn
import scala.collection.mutable
trait MacroHandler(implicit withSchemaValidation: ValidationMode) { this: AstCreator =>
private val nodeOffsetMacroPairs: mutable.Stack[(Int, IASTPreprocessorMacroDefinition)] = {
mutable.Stack.from(
cdtAst.getNodeLocations.toList
.collect { case exp: IASTMacroExpansionLocation =>
(exp.asFileLocation().getNodeOffset, exp.getExpansion.getMacroDefinition)
}
.sortBy(_._1)
)
}
/** For the given node, determine if it is expanded from a macro, and if so, create a Call node to represent the macro
* invocation and attach `ast` as its child.
*/
def asChildOfMacroCall(node: IASTNode, ast: Ast): Ast = {
// If a macro in a header file contained a method definition already seen in some
// source file we skipped that during the previous AST creation and returned an empty AST.
if (ast.root.isEmpty && isExpandedFromMacro(node)) return ast
// We do nothing for locals only.
if (ast.nodes.size == 1 && ast.root.exists(_.isInstanceOf[NewLocal])) return ast
// Otherwise, we create the synthetic call AST.
val matchingMacro = extractMatchingMacro(node)
val macroCallAst = matchingMacro.map { case (mac, args) => createMacroCallAst(ast, node, mac, args) }
macroCallAst match {
case Some(callAst) =>
val lostLocals = ast.refEdges.collect { case AstEdge(_, dst: NewLocal) => Ast(dst) }.toList
val newAst = ast.subTreeCopy(ast.root.get.asInstanceOf[AstNodeNew], argIndex = 1)
// We need to wrap the copied AST as it may contain CPG nodes not being allowed
// to be connected via AST edges under a CALL. E.g., LOCALs but only if its not already a BLOCK.
val childAst = newAst.root match {
case Some(_: NewBlock) =>
newAst
case _ =>
val b = NewBlock().argumentIndex(1).typeFullName(registerType(Defines.Void))
blockAst(b, List(newAst))
}
callAst.withChildren(lostLocals).withChild(childAst)
case None => ast
}
}
/** For the given node, determine if it is expanded from a macro, and if so, find the first matching (offset, macro)
* pair in nodeOffsetMacroPairs, removing non-matching elements from the start of nodeOffsetMacroPairs. Returns
* (Some(macroDefinition, arguments)) if a macro definition matches and None otherwise.
*/
private def extractMatchingMacro(node: IASTNode): Option[(IASTPreprocessorMacroDefinition, List[String])] = {
val expansionLocations = expandedFromMacro(node).filterNot(isExpandedFrom(node.getParent, _))
val nodeOffset = node.getFileLocation.getNodeOffset
var matchingMacro = Option.empty[(IASTPreprocessorMacroDefinition, List[String])]
expansionLocations.foreach { macroLocation =>
while (matchingMacro.isEmpty && nodeOffsetMacroPairs.headOption.exists(_._1 <= nodeOffset)) {
val (_, macroDefinition) = nodeOffsetMacroPairs.pop()
val macroExpansionName = ASTStringUtil.getSimpleName(macroLocation.getExpansion.getMacroDefinition.getName)
val macroDefinitionName = ASTStringUtil.getSimpleName(macroDefinition.getName)
if (macroExpansionName == macroDefinitionName) {
val arguments = new MacroArgumentExtractor(cdtAst, node.getFileLocation).getArguments
matchingMacro = Option((macroDefinition, arguments))
}
}
}
matchingMacro
}
/** Determine whether `node` is expanded from the macro expansion at `loc`.
*/
private def isExpandedFrom(node: IASTNode, loc: IASTMacroExpansionLocation): Boolean =
expandedFromMacro(node).map(_.getExpansion.getMacroDefinition).contains(loc.getExpansion.getMacroDefinition)
private def argumentTrees(arguments: List[String], ast: Ast): List[Option[Ast]] = {
arguments.zipWithIndex.map { case (arg, i) =>
val rootNode = argForCode(arg, ast)
rootNode.map(x => ast.subTreeCopy(x.asInstanceOf[AstNodeNew], i + 1))
}
}
private def argForCode(code: String, ast: Ast): Option[NewNode] = {
val normalizedCode = code.replace(" ", "")
if (normalizedCode == "") {
None
} else {
ast.nodes.collectFirst {
case x: ExpressionNew if !x.isInstanceOf[NewFieldIdentifier] && x.code == normalizedCode => x
}
}
}
/** Create an AST that represents a macro expansion as a call. The AST is rooted in a CALL node and contains sub trees
* for arguments. These are also connected to the AST via ARGUMENT edges. We include line number information in the
* CALL node that is picked up by the MethodStubCreator.
*/
private def createMacroCallAst(
ast: Ast,
node: IASTNode,
macroDef: IASTPreprocessorMacroDefinition,
arguments: List[String]
): Ast = {
val name = ASTStringUtil.getSimpleName(macroDef.getName)
val code = node.getRawSignature.stripSuffix(";")
val argAsts = argumentTrees(arguments, ast).map(_.getOrElse(Ast()))
val callName = StringUtils.normalizeSpace(name)
val callFullName = StringUtils.normalizeSpace(fullName(macroDef, argAsts))
val callNode =
NewCall()
.name(callName)
.dispatchType(DispatchTypes.INLINED)
.methodFullName(callFullName)
.code(code)
.typeFullName(typeFor(node))
.lineNumber(line(node))
.columnNumber(column(node))
callAst(callNode, argAsts)
}
/** Create a full name field that encodes line information that can be picked up by the MethodStubCreator in order to
* create a METHOD node with the correct location information.
*/
private def fullName(macroDef: IASTPreprocessorMacroDefinition, argAsts: List[Ast]) = {
val name = ASTStringUtil.getSimpleName(macroDef.getName)
val filename = fileName(macroDef)
val lineNo: Integer = line(macroDef).getOrElse(-1)
val lineNoEnd: Integer = lineEnd(macroDef).getOrElse(-1)
s"$filename:$lineNo:$lineNoEnd:$name:${argAsts.size}"
}
/** The CDT utility method is unfortunately in a class that is marked as deprecated, however, this is because the CDT
* team would like to discourage its use but at the same time does not plan to remove this code.
*/
@nowarn
def nodeSignature(node: IASTNode): String = {
import org.eclipse.cdt.core.dom.ast.ASTSignatureUtil.getNodeSignature
if (isExpandedFromMacro(node)) {
val sig = getNodeSignature(node)
if (sig.isEmpty) {
node.getRawSignature
} else {
sig
}
} else {
node.getRawSignature
}
}
private def isExpandedFromMacro(node: IASTNode): Boolean = expandedFromMacro(node).nonEmpty
private def expandedFromMacro(node: IASTNode): Option[IASTMacroExpansionLocation] = {
val locations = node.getNodeLocations.toList
val locationsSorted = node match {
// For binary expressions the expansion locations may occur in any order.
// We manually sort them here to ignore this.
// TODO: This may also happen with other expressions that allow for multiple sub elements.
case _: IASTBinaryExpression => locations.sortBy(_.isInstanceOf[IASTMacroExpansionLocation])
case _ => locations
}
locationsSorted match {
case (head: IASTMacroExpansionLocation) :: _ => Option(head)
case _ => None
}
}
}
