From 11ec93bfdbf8bd73a4c22bf586ce474ef5deeea4 Mon Sep 17 00:00:00 2001
From: chaoticgd <43898262+chaoticgd@users.noreply.github.com>
Date: Mon, 4 Sep 2023 22:33:43 +0100
Subject: [PATCH] Fix the existing __vtbl_ptr_type instead of creating a new
 one

---
 .../symboltable/StabsImporter.java            | 55 +++++++++----------
 .../emotionengine/symboltable/StdumpAST.java  |  5 --
 2 files changed, 25 insertions(+), 35 deletions(-)

diff --git a/src/main/java/ghidra/emotionengine/symboltable/StabsImporter.java b/src/main/java/ghidra/emotionengine/symboltable/StabsImporter.java
index b986452..e350664 100644
--- a/src/main/java/ghidra/emotionengine/symboltable/StabsImporter.java
+++ b/src/main/java/ghidra/emotionengine/symboltable/StabsImporter.java
@@ -235,9 +235,6 @@ public void importDataTypes(StdumpAST.ImporterState importer) {
 			}
 		}
 		
-		// Create a type for the vtable pointer.
-		createVtablePointerType(importer);
-		
 		// Create all the top-level enums, structs and unions first.
 		for(int i = 0; i < type_count; i++) {
 			StdumpAST.Node node = importer.ast.deduplicatedTypes.get(i);
@@ -248,14 +245,28 @@ public void importDataTypes(StdumpAST.ImporterState importer) {
 				importer.types.add(importer.programTypeManager.addDataType(type, null));
 			} else if(node instanceof StdumpAST.InlineStructOrUnion) {
 				StdumpAST.InlineStructOrUnion structOrUnion = (StdumpAST.InlineStructOrUnion) node;
-				DataType type = structOrUnion.createEmpty(importer);
-				importer.types.add(importer.programTypeManager.addDataType(type, null));
+				boolean isVtablePointerType = structOrUnion.name.equals("__vtbl_ptr_type");
+				if(isVtablePointerType) {
+					fixVtablePointerType(structOrUnion);
+				}
+				DataType createdType = structOrUnion.createEmpty(importer);
+				DataType addedType = importer.programTypeManager.addDataType(createdType, null);
+				if(isVtablePointerType) {
+					importer.vtablePointerType = addedType;
+				}
+				importer.types.add(addedType);
+				
 			} else {
 				importer.types.add(null);
 			}
 			monitor.setProgress(i);
 		}
-
+		
+		// If __vtbl_ptr_type isn't a struct, we assume it's a pointer.
+		if(importer.vtablePointerType == null) {
+			importer.vtablePointerType = PointerDataType.dataType;
+		}
+		
 		// Fill in the structs and unions recursively.
 		for(int i = 0; i < type_count; i++) {
 			StdumpAST.Node node = importer.ast.deduplicatedTypes.get(i);
@@ -270,33 +281,17 @@ public void importDataTypes(StdumpAST.ImporterState importer) {
 		}
 	}
 	
-	public void createVtablePointerType(StdumpAST.ImporterState importer) {
-		Integer typeIndex = importer.typeNameToDeduplicatedTypeIndex.get("__vtbl_ptr_type");
-		if(typeIndex == null) {
-			importer.vtablePointerTypeReportError = true;
-			importer.vtablePointerType = PointerDataType.dataType;
-			return;
-		}
-		
-		StdumpAST.Node node = importer.ast.deduplicatedTypes.get(typeIndex);
-		
+	public void fixVtablePointerType(StdumpAST.InlineStructOrUnion vtablePointerType) {
 		// For some compiler versions __vtbl_ptr_type is just a function
 		// pointer, for others it's a struct containing some integers and a
-		// function pointer. In the latter case the stab generated for that type
-		// is weird, so we recreate it from scratch.
-		if(node.sizeBits == 64) {
-			StructureDataType type = new StructureDataType("__vtbl_ptr_type_ccc", 8, importer.programTypeManager);
-			type.setDescription("Generated by the STABS importer.");
-			try {
-				type.replaceAtOffset(0, ShortDataType.dataType, 2, "__delta", null);
-				type.replaceAtOffset(2, ShortDataType.dataType, 2, "__index", null);
-				type.replaceAtOffset(4, PointerDataType.dataType, 4, "__pfn", null);
-			} catch(IllegalArgumentException e) {
-				importer.log.appendException(e);
+		// function pointer. In the latter case, the stab provided in the symbol
+		// table leads to incorrect decompilation of virtual function calls, so
+		// we need to fix it up here.
+		for(StdumpAST.Node field : vtablePointerType.fields) {
+			if(field.name.equals("__delta2")) {
+				vtablePointerType.fields.remove(field);
+				break;
 			}
-			importer.vtablePointerType = importer.programTypeManager.addDataType(type, null);
-		} else {
-			importer.vtablePointerType = PointerDataType.dataType;
 		}
 	}
 	
diff --git a/src/main/java/ghidra/emotionengine/symboltable/StdumpAST.java b/src/main/java/ghidra/emotionengine/symboltable/StdumpAST.java
index b4b693a..dba8d85 100644
--- a/src/main/java/ghidra/emotionengine/symboltable/StdumpAST.java
+++ b/src/main/java/ghidra/emotionengine/symboltable/StdumpAST.java
@@ -64,7 +64,6 @@ public static class ImporterState {
 		HashMap<String, StructureDataType> forwardDeclaredTypes = new HashMap<>();
 		ArrayList<String> prefixStack = new ArrayList<>(); // Used to name nested structs.
 		DataType vtablePointerType;
-		boolean vtablePointerTypeReportError = false;
 		
 		// Ghidra objects.
 		TaskMonitor monitor;
@@ -422,10 +421,6 @@ public void fillVtable(StructureDataType dest, ImporterState importer) {
 						} catch(IllegalArgumentException e) {
 							importer.log.appendException(e);
 						}
-						if(importer.vtablePointerTypeReportError) {
-							importer.log.appendMsg("STABS", "Cannot find type '__vtbl_ptr_type'. Generated C++ vtables may be incorrect.");
-							importer.vtablePointerTypeReportError = false;
-						}
 					}
 				}
 			}