GT-2882 - Decompiler - Updated to set the cursor to the function

signature when a new function is loaded

Ghidra/Features/Decompiler/src/main/java/ghidra/app/decompiler/component/DecompilerPanel.java

@@ -203,25 +203,77 @@ public class DecompilerPanel extends JPanel implements FieldMouseListener, Field
 
 	public void setLocation(ProgramLocation location, ViewerPosition viewerPosition) {
 		repaint();
-		Address address = location.getAddress();
-		if (address == null) {
+		if (location.getAddress() == null) {
 			return;
 		}
+
 		if (viewerPosition != null) {
 			fieldPanel.setViewerPosition(viewerPosition.getIndex(), viewerPosition.getXOffset(),
 				viewerPosition.getYOffset());
 		}
-		List<ClangToken> tokens =
-			DecompilerUtils.getTokens(layoutMgr.getRoot(), translateAddress(address));
 
 		if (location instanceof DecompilerLocation) {
 			DecompilerLocation decompilerLocation = (DecompilerLocation) location;
 			fieldPanel.goTo(BigInteger.valueOf(decompilerLocation.getLineNumber()), 0, 0,
 				decompilerLocation.getCharPos(), false);
+			return;
 		}
-		else if (!tokens.isEmpty()) {
-			goToBeginningOfLine(tokens);
+
+		//
+		// Try to figure out where the given location's address maps to.  If we can find the
+		// line that contains the address, the go to the beginning of that line.  (We do not try
+		// to go to an actual token, since multiple tokens can share an address, we woudln't know
+		// which token is best.)
+		//
+		// Note:  at the time of this writing, not all fields have an address value.  For 
+		//        example, the ClangFuncNameToken, does not have an address.  (It seems that most
+		//        of the tokens in the function signature do not have an address, which can 
+		//        probably be fixed.)   So, to deal with this oddity, we will have some special
+		//        case code below.
+		//
+		Address address = location.getAddress();
+		if (goToFunctionSignature(address)) {
+			// special case: the address is at the function entry, which means we just navigate
+			// to the signature
+			return;
 		}
+
+		Address translated = translate(address);
+		List<ClangToken> tokens =
+			DecompilerUtils.getTokensFromView(layoutMgr.getFields(), translated);
+		goToBeginningOfLine(tokens);
+	}
+
+	private boolean goToFunctionSignature(Address address) {
+
+		Address entry = decompileData.getFunction().getEntryPoint();
+		if (!entry.equals(address)) {
+			return false;
+		}
+
+		List<ClangLine> lines = layoutMgr.getLines();
+		ClangLine signatureLine = getFunctionSignatureLine(lines);
+		if (signatureLine == null) {
+			return false; // can happen when there is no function decompiled
+		}
+
+		// -1 since the FieldPanel is 0-based; we are 1-based
+		int lineNumber = signatureLine.getLineNumber() - 1;
+		fieldPanel.goTo(BigInteger.valueOf(lineNumber), 0, 0, 0, false);
+
+		return true;
+	}
+
+	private ClangLine getFunctionSignatureLine(List<ClangLine> functionLines) {
+		for (ClangLine line : functionLines) {
+			List<ClangToken> tokens = line.getAllTokens();
+			for (ClangToken token : tokens) {
+				if (token.Parent() instanceof ClangFuncProto) {
+					return line;
+				}
+			}
+		}
+		return null;
 	}
 
 	/**
@@ -229,6 +281,10 @@ public class DecompilerPanel extends JPanel implements FieldMouseListener, Field
 	 * @param tokens the tokens to search for 
 	 */
 	private void goToBeginningOfLine(List<ClangToken> tokens) {
+		if (tokens.isEmpty()) {
+			return;
+		}
+
 		int firstLineNumber = DecompilerUtils.findIndexOfFirstField(tokens, layoutMgr.getFields());
 		if (firstLineNumber != -1) {
 			fieldPanel.goTo(BigInteger.valueOf(firstLineNumber), 0, 0, 0, false);
@@ -290,7 +346,7 @@ public class DecompilerPanel extends JPanel implements FieldMouseListener, Field
 	 * @param addr the Ghidra address
 	 * @return the decompiler address
 	 */
-	private Address translateAddress(Address addr) {
+	private Address translate(Address addr) {
 		Function func = decompileData.getFunction();
 		if (func == null) {
 			return addr;
@@ -418,7 +474,7 @@ public class DecompilerPanel extends JPanel implements FieldMouseListener, Field
 		ClangTextField textField = (ClangTextField) field;
 		ClangToken token = textField.getToken(location);
 		if (token instanceof ClangFuncNameToken) {
-			tryGoToFunction(token, newWindow);
+			tryGoToFunction((ClangFuncNameToken) token, newWindow);
 		}
 		else if (token instanceof ClangLabelToken) {
 			tryGoToLabel((ClangLabelToken) token, newWindow);
@@ -451,16 +507,15 @@ public class DecompilerPanel extends JPanel implements FieldMouseListener, Field
 		tryGoToScalar(word, newWindow);
 	}
 
-	private void tryGoToFunction(ClangToken token, boolean newWindow) {
-		Function function =
-			DecompilerUtils.getFunction(controller.getProgram(), (ClangFuncNameToken) token);
+	private void tryGoToFunction(ClangFuncNameToken functionToken, boolean newWindow) {
+		Function function = DecompilerUtils.getFunction(controller.getProgram(), functionToken);
 		if (function != null) {
 			controller.goToFunction(function, newWindow);
 			return;
 		}
 
 		// TODO no idea what this is supposed to be handling...someone doc this please
-		String labelName = token.getText();
+		String labelName = functionToken.getText();
 		if (labelName.startsWith("func_0x")) {
 			try {
 				Address addr =

Ghidra/Features/Decompiler/src/main/java/ghidra/app/decompiler/component/DecompilerUtils.java

@@ -24,24 +24,29 @@ import ghidra.program.model.address.*;
 import ghidra.program.model.listing.Function;
 import ghidra.program.model.listing.Program;
 import ghidra.program.model.pcode.*;
+import ghidra.util.Msg;
 
 public class DecompilerUtils {
 
 	/**
-	 * If the token refers to an individual Varnode, return it. Otherwise return null;
+	 * If the token refers to an individual Varnode, return it. Otherwise return null
+	 * 
+	 * @param token the token to check
 	 * @return the Varnode or null otherwise
 	 */
-	public static Varnode getVarnodeRef(ClangToken vartoken) {
-		if (vartoken == null) {
+	public static Varnode getVarnodeRef(ClangToken token) {
+		if (token == null) {
 			return null;
 		}
-		if (vartoken instanceof ClangVariableToken) {
-			Varnode res = vartoken.getVarnode();
+
+		if (token instanceof ClangVariableToken) {
+			Varnode res = token.getVarnode();
 			if (res != null) {
 				return res;
 			}
 		}
-		ClangNode parent = vartoken.Parent();
+
+		ClangNode parent = token.Parent();
 		if (parent instanceof ClangVariableDecl) {
 			HighVariable high = ((ClangVariableDecl) parent).getHighVariable();
 			parent = parent.Parent();
@@ -63,8 +68,8 @@ public class DecompilerUtils {
 	 * @return set of Varnodes in the slice
 	 */
 	public static Set<Varnode> getForwardSlice(Varnode seed) {
-		HashSet<Varnode> varnodes = new HashSet<>();
-		ArrayList<Varnode> worklist = new ArrayList<>();
+		Set<Varnode> varnodes = new HashSet<>();
+		List<Varnode> worklist = new ArrayList<>();
 		worklist.add(seed);
 
 		for (int i = 0; i < worklist.size(); i++) {
@@ -97,8 +102,8 @@ public class DecompilerUtils {
 	}
 
 	public static Set<Varnode> getBackwardSlice(Varnode seed) {
-		HashSet<Varnode> varnodes = new HashSet<>();
-		ArrayList<Varnode> worklist = new ArrayList<>();
+		Set<Varnode> varnodes = new HashSet<>();
+		List<Varnode> worklist = new ArrayList<>();
 		worklist.add(seed);
 
 		for (int i = 0; i < worklist.size(); i++) {
@@ -209,7 +214,12 @@ public class DecompilerUtils {
 	}
 
 	/**
-	 * @return the function referenced by the given token
+	 * Returns the function represented by the given token.  This will be either the 
+	 * decompiled function or a function referenced within the decompiled function.
+	 * 
+	 * @param program the progam
+	 * @param token the token
+	 * @return the function
 	 */
 	public static Function getFunction(Program program, ClangFuncNameToken token) {
 
@@ -221,6 +231,7 @@ public class DecompilerUtils {
 				return clangFunction.getHighFunction().getFunction();
 			}
 		}
+
 		if (parent instanceof ClangStatement) {
 			// sub-function call
 			PcodeOp pcodeOp = token.getPcodeOp();
@@ -239,6 +250,10 @@ public class DecompilerUtils {
 	 * @return index of field, or -1
 	 */
 	public static int findIndexOfFirstField(List<ClangToken> queryTokens, Field[] fields) {
+		if (queryTokens.isEmpty()) {
+			return -1;
+		}
+
 		for (int i = 0; i < fields.length; i++) {
 			ClangTextField f = (ClangTextField) fields[i];
 			List<ClangToken> fieldTokens = f.getTokens();
@@ -252,6 +267,32 @@ public class DecompilerUtils {
 		return -1;
 	}
 
+	/**
+	 * Similar to {@link #getTokens(ClangNode, AddressSetView)}, but uses the tokens from
+	 * the given view fields.  Sometimes the tokens in the model (represented by the 
+	 * {@link ClangNode}) are different than the fields in the view (such as when a list of 
+	 * comment tokens are condensed into a single comment token).
+	 * 
+	 * @param fields the fields to check
+	 * @param address the address each returned token must match
+	 * @return the matching tokens
+	 */
+	public static List<ClangToken> getTokensFromView(Field[] fields, Address address) {
+
+		AddressSetView set = new AddressSet(address);
+		List<ClangToken> result = new ArrayList<>();
+		for (Field f : fields) {
+			ClangTextField tf = (ClangTextField) f;
+			List<ClangToken> fieldTokens = tf.getTokens();
+			for (ClangToken token : fieldTokens) {
+				if (intersects(token, set)) {
+					result.add(token);
+				}
+			}
+		}
+		return result;
+	}
+
 	/**
 	 * Find all ClangNodes that have a minimum address in the AddressSetView
 	 * @param root the root of the token tree
@@ -265,26 +306,8 @@ public class DecompilerUtils {
 	}
 
 	public static List<ClangToken> getTokens(ClangNode root, Address address) {
-		List<ClangToken> tokenList = new ArrayList<>();
-		collectTokens(tokenList, root, address);
-		return tokenList;
-	}
-
-	private static void collectTokens(List<ClangToken> tokenList, ClangNode parentNode,
-			Address address) {
-		int nchild = parentNode.numChildren();
-		for (int i = 0; i < nchild; i++) {
-			ClangNode node = parentNode.Child(i);
-			if (node.numChildren() > 0) {
-				collectTokens(tokenList, node, address);
-			}
-			else if (node instanceof ClangToken) {
-				ClangToken token = (ClangToken) node;
-				if (intersects(token, address)) {
-					tokenList.add((ClangToken) node);
-				}
-			}
-		}
+		AddressSet set = new AddressSet(address);
+		return getTokens(root, set);
 	}
 
 	private static void collectTokens(List<ClangToken> tokenList, ClangNode parentNode,
@@ -292,6 +315,11 @@ public class DecompilerUtils {
 		int nchild = parentNode.numChildren();
 		for (int i = 0; i < nchild; i++) {
 			ClangNode node = parentNode.Child(i);
+
+			if (node instanceof ClangFuncProto) {
+				Msg.debug(null, "");
+			}
+
 			if (node.numChildren() > 0) {
 				collectTokens(tokenList, node, addressSet);
 			}
@@ -314,18 +342,6 @@ public class DecompilerUtils {
 		return addressSet.intersects(minAddress, maxAddress);
 	}
 
-	private static boolean intersects(ClangToken token, Address address) {
-		Address minAddress = token.getMinAddress();
-		if (minAddress == null) {
-			return false;
-		}
-		Address maxAddress = token.getMaxAddress();
-		if (maxAddress == null) {
-			return minAddress.equals(maxAddress);
-		}
-		return address.compareTo(minAddress) >= 0 && address.compareTo(maxAddress) <= 0;
-	}
-
 	public static Address getClosestAddress(ClangToken token) {
 		Address address = token.getMinAddress();
 		if (address != null) {
@@ -378,7 +394,7 @@ public class DecompilerUtils {
 	/**
 	 * Find closest addressed token to a specified token or null if one is not found.
 	 * Only adjacent tokens on the same line are examined.
-	 * @param token
+	 * @param token the query token
 	 * @return closest addressed token
 	 */
 	private static ClangToken findClosestAddressedToken(ClangToken token) {

Ghidra/Features/Decompiler/src/test.slow/java/ghidra/app/plugin/core/decompile/DecompilerClangTest.java

@@ -15,7 +15,7 @@
  */
 package ghidra.app.plugin.core.decompile;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.*;
 
 import java.util.List;
 
@@ -97,6 +97,20 @@ public class DecompilerClangTest extends AbstractDecompilerTest {
 		assertCurrentAddress(addr(linkAddress));
 	}
 
+	@Test
+	public void testNewDecompileNavigatesToFunctionSignature() {
+
+		decompile("100000bf0"); // 'main'
+		int line = 5; // arbitrary value in view
+		int charPosition = 5; // arbitrary
+		setDecompilerLocation(line, charPosition);
+
+		decompile("100000d60"); // _call_structure_A()
+		line = 0; // function signature
+		charPosition = 0; // start of signature
+		assertCurrentLocation(line, charPosition);
+	}
+
 //==================================================================================================
 // Private Methods
 //==================================================================================================
@@ -141,6 +155,14 @@ public class DecompilerClangTest extends AbstractDecompilerTest {
 		assertEquals("Line text not as expected at line " + line, expected, actual);
 	}
 
+	private void assertCurrentLocation(int line, int col) {
+		int oneBasedLine = line + 1;
+		DecompilerPanel panel = provider.getDecompilerPanel();
+		FieldLocation actual = panel.getCursorPosition();
+		FieldLocation expected = loc(oneBasedLine, col);
+		assertEquals("Decompiler cursor is not at the expected location", expected, actual);
+	}
+
 	private String getTokenText(FieldLocation loc) {
 		ClangTextField field = getFieldForLine(loc.getIndex().intValue());
 		ClangToken token = field.getToken(loc);