Candidate release of source code.

Ghidra/Features/Base/ghidra_scripts/Mips_Fix_T9_PositionIndependentCode.java

@@ -0,0 +1,120 @@
+/* ###
+ * IP: GHIDRA
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+// Mips_Fix_T9_PositionIndependentCode is useful for a particular PIC (position independent code) trick used by some compilers.
+// The T9 register is used as a base for all address calculations in each function.  The T9 register
+// is set to the start of each function right before the function is called.  This is done by actually
+// using the T9 register to call the other function.
+//
+// This could be modified if there is some other register being used.  However the compiler would need.
+// to know this as it creates code, so it really is a calling convention.
+//
+// Usage:  This relies on functions having been created, so if a new function is created, you must
+// re-run the script again.
+//
+// Important: Since it relies on functions being created, one should endeavor to find all function starts
+// and actually create a function, then run this script.
+//
+// Future: This could be created as an automated analyzer, if one could detect that it should be run.
+//
+//@category Analysis.MIPS
+//@keybinding 
+//@menupath 
+//@toolbar 
+
+import java.math.BigInteger;
+
+import ghidra.app.plugin.core.analysis.AutoAnalysisManager;
+import ghidra.app.script.GhidraScript;
+import ghidra.app.script.GhidraState;
+import ghidra.program.model.address.Address;
+import ghidra.program.model.address.AddressSet;
+import ghidra.program.model.lang.Register;
+import ghidra.program.model.listing.*;
+import ghidra.program.util.ProgramLocation;
+
+public class Mips_Fix_T9_PositionIndependentCode extends GhidraScript {
+
+	@Override
+	public void run() throws Exception {
+		AddressSet doneSet = new AddressSet();
+
+		while (processFunctions(doneSet)) {
+			this.analyzeChanges(currentProgram);
+		}
+
+	}
+
+	private boolean processFunctions(AddressSet doneSet) {
+		Listing listing = currentProgram.getListing();
+
+		Register t9 = currentProgram.getRegister("t9");
+		if (t9 == null) {
+			return false;
+		}
+
+		FunctionIterator fiter = listing.getFunctions(true);
+		boolean didAnything = false;
+		while (!monitor.isCancelled() && fiter.hasNext()) {
+			Function func = fiter.next();
+
+			Address funcEntry = func.getEntryPoint();
+
+			if (doneSet.contains(funcEntry)) {
+				continue;
+			}
+			doneSet.addRange(funcEntry, funcEntry);
+			Instruction instr = listing.getInstructionAt(funcEntry);
+			if (instr == null) {
+				continue;
+			}
+
+			currentAddress = funcEntry;
+			if (instr.getValue(t9, false) != null) {
+				continue;
+			}
+
+			didAnything = true;
+
+			println("" + func.getName());
+
+			try {
+				instr.setValue(t9, BigInteger.valueOf(funcEntry.getOffset()));
+			}
+			catch (ContextChangeException e) {
+				println("  COULDN'T set context");
+				e.printStackTrace();
+			}
+
+			GhidraState newState =
+				new GhidraState(state.getTool(), state.getProject(), currentProgram,
+					new ProgramLocation(currentProgram, currentAddress), null, null);
+
+			try {
+				this.runScript("PropagateConstantReferences.java", newState);
+			}
+			catch (Exception e) {
+				println("Couldn't Run Propogate script");
+				e.printStackTrace();
+			}
+
+			AutoAnalysisManager amgr = AutoAnalysisManager.getAnalysisManager(currentProgram);
+			amgr.codeDefined(func.getBody());
+		}
+
+		return didAnything;
+	}
+
+}