[ghidra2cpg] Simplify checking of external functions (#5449)

Author: gemesa

joern-cli/frontends/ghidra2cpg/src/main/scala/io/joern/ghidra2cpg/passes/PCodePass.scala

@@ -117,8 +117,8 @@ class PCodePass(currentProgram: Program, fileName: String, functions: List[Funct
   override def runOnPart(diffGraphBuilder: DiffGraphBuilder, function: Function): Unit = {
     val localDiffGraph = Cpg.newDiffGraphBuilder
     // we need it just once with default settings
-    val blockNode  = nodes.NewBlock().code("").order(0)
-    val methodNode = createMethodNode(decompiler, function, fileName, checkIfExternal(currentProgram, function.getName))
+    val blockNode    = nodes.NewBlock().code("").order(0)
+    val methodNode   = createMethodNode(decompiler, function, fileName)
     val methodReturn = createReturnNode()
 
     localDiffGraph.addNode(methodNode)

joern-cli/frontends/ghidra2cpg/src/main/scala/io/joern/ghidra2cpg/passes/arm/ArmFunctionPass.scala

@@ -4,7 +4,7 @@ import ghidra.program.model.listing.{Function, Program}
 import io.joern.ghidra2cpg.utils.Decompiler
 import io.joern.ghidra2cpg.passes.FunctionPass
 import io.joern.ghidra2cpg.processors.ArmProcessor
-import io.joern.ghidra2cpg.utils.Utils.{checkIfExternal, createMethodNode, createReturnNode}
+import io.joern.ghidra2cpg.utils.Utils.{createMethodNode, createReturnNode}
 import io.shiftleft.codepropertygraph.generated.nodes.NewBlock
 import io.shiftleft.codepropertygraph.generated.{Cpg, EdgeTypes, nodes}
 
@@ -22,7 +22,7 @@ class ArmFunctionPass(
     val blockNode: NewBlock = nodes.NewBlock().code("").order(0)
     try {
       val methodNode =
-        createMethodNode(decompiler, function, filename, checkIfExternal(currentProgram, function.getName))
+        createMethodNode(decompiler, function, filename)
       val methodReturn = createReturnNode()
       localDiffGraph.addNode(methodNode)
       localDiffGraph.addNode(blockNode)

joern-cli/frontends/ghidra2cpg/src/main/scala/io/joern/ghidra2cpg/passes/mips/MipsFunctionPass.scala

@@ -261,8 +261,8 @@ class MipsFunctionPass(
     val localDiffGraph = Cpg.newDiffGraphBuilder
     // we need it just once with default settings
     val blockNode: NewBlock = nodes.NewBlock().code("").order(0)
-    val methodNode = createMethodNode(decompiler, function, filename, checkIfExternal(currentProgram, function.getName))
-    val methodReturn = createReturnNode()
+    val methodNode          = createMethodNode(decompiler, function, filename)
+    val methodReturn        = createReturnNode()
     localDiffGraph.addNode(methodNode)
     localDiffGraph.addNode(blockNode)
     localDiffGraph.addEdge(methodNode, blockNode, EdgeTypes.AST)

joern-cli/frontends/ghidra2cpg/src/main/scala/io/joern/ghidra2cpg/passes/x86/X86FunctionPass.scala

@@ -50,7 +50,7 @@ class X86FunctionPass(
     // we need it just once with default settings
     val blockNode: NewBlock = nodes.NewBlock().code("").order(0)
     val methodNode =
-      createMethodNode(decompiler, function, filename, checkIfExternal(currentProgram, function.getName))
+      createMethodNode(decompiler, function, filename)
     val localGraphBuilder = Cpg.newDiffGraphBuilder
     val methodReturn      = createReturnNode()
     localGraphBuilder.addNode(methodNode)

joern-cli/frontends/ghidra2cpg/src/main/scala/io/joern/ghidra2cpg/utils/Utils.scala

@@ -64,8 +64,9 @@ object Utils {
   def createReturnNode(): NewMethodReturn = {
     NewMethodReturn().order(1)
   }
-  def createMethodNode(decompiler: Decompiler, function: Function, fileName: String, isExternal: Boolean): NewMethod = {
-    val code = decompiler.toDecompiledFunction(function).map(_.getC).getOrElse("")
+  def createMethodNode(decompiler: Decompiler, function: Function, fileName: String): NewMethod = {
+    val code       = decompiler.toDecompiledFunction(function).map(_.getC).getOrElse("")
+    val isExternal = Option(function.getThunkedFunction(true)).map(_.isExternal).getOrElse(function.isExternal)
     val lineNumberEnd = Option(function.getReturn)
       .flatMap(x => Option(x.getMinAddress))
       .flatMap(x => Option(x.getOffsetAsBigInteger))
@@ -86,13 +87,6 @@ object Utils {
       .astParentType(NodeTypes.NAMESPACE_BLOCK)
       .astParentFullName(s"$fileName:<global>")
   }
-  def checkIfExternal(currentProgram: Program, functionName: String): Boolean = {
-    currentProgram.getFunctionManager.getExternalFunctions
-      .iterator()
-      .asScala
-      .map(_.getName)
-      .contains(functionName)
-  }
   def getInstructions(program: Program, function: Function): Seq[Instruction] =
     program.getListing.getInstructions(function.getBody, true).iterator().asScala.toList