refactor: Add more opcodes to findFreeRegister

patches/src/main/kotlin/app/revanced/patches/youtube/layout/hide/general/HideLayoutComponentsPatch.kt

@@ -269,7 +269,7 @@ val hideLayoutComponentsPatch = bytecodePatch(
                         move-object v$returnEmptyComponentRegister, p1   # Required for 19.47
                         goto :return_empty_component
                         :show
-                        const/4 v$freeRegister, 0x0   # Restore register, required for 19.16
+                        nop
                     """,
                     ExternalLabel("return_empty_component", returnEmptyComponentInstruction),
                 )

patches/src/main/kotlin/app/revanced/patches/youtube/layout/returnyoutubedislike/ReturnYouTubeDislikePatch.kt

@@ -179,9 +179,6 @@ val returnYouTubeDislikePatch = bytecodePatch(
 
         // region Hook rolling numbers.
 
-        // Do this last to allow patching old unsupported versions (if the user really wants),
-        // On older unsupported version this will fail to match and throw an exception,
-        // but everything will still work correctly anyway.
         val dislikesIndex = rollingNumberSetterFingerprint.patternMatch!!.endIndex
 
         rollingNumberSetterFingerprint.method.apply {

patches/src/main/kotlin/app/revanced/util/BytecodeUtils.kt

@@ -70,21 +70,53 @@ internal fun Method.findFreeRegister(startIndex: Int, vararg registersToExclude:
     }
 
     val writeOpcodes = EnumSet.of(
+        ARRAY_LENGTH,
         NEW_INSTANCE, NEW_ARRAY,
         MOVE, MOVE_FROM16, MOVE_16, MOVE_WIDE, MOVE_WIDE_FROM16, MOVE_WIDE_16, MOVE_OBJECT,
         MOVE_OBJECT_FROM16, MOVE_OBJECT_16, MOVE_RESULT, MOVE_RESULT_WIDE, MOVE_RESULT_OBJECT, MOVE_EXCEPTION,
+        CONST, CONST_4, CONST_16, CONST_HIGH16, CONST_WIDE_16, CONST_WIDE_32,
+        CONST_WIDE, CONST_WIDE_HIGH16, CONST_STRING, CONST_STRING_JUMBO,
         IGET, IGET_WIDE, IGET_OBJECT, IGET_BOOLEAN, IGET_BYTE, IGET_CHAR, IGET_SHORT,
+        IGET_VOLATILE, IGET_WIDE_VOLATILE, IGET_OBJECT_VOLATILE,
         SGET, SGET_WIDE, SGET_OBJECT, SGET_BOOLEAN, SGET_BYTE, SGET_CHAR, SGET_SHORT,
+        SGET_VOLATILE, SGET_WIDE_VOLATILE, SGET_OBJECT_VOLATILE,
+        AGET, AGET_WIDE, AGET_OBJECT, AGET_BOOLEAN, AGET_BYTE, AGET_CHAR, AGET_SHORT,
+        // Arithmetic and logical operations.
+        ADD_DOUBLE_2ADDR, ADD_DOUBLE, ADD_FLOAT_2ADDR, ADD_FLOAT, ADD_INT_2ADDR,
+        ADD_INT_LIT8, ADD_INT, ADD_LONG_2ADDR, ADD_LONG, ADD_INT_LIT16,
+        AND_INT_2ADDR, AND_INT_LIT8, AND_INT_LIT16, AND_INT, AND_LONG_2ADDR, AND_LONG,
+        DIV_DOUBLE_2ADDR, DIV_DOUBLE, DIV_FLOAT_2ADDR, DIV_FLOAT, DIV_INT_2ADDR,
+        DIV_INT_LIT16, DIV_INT_LIT8, DIV_INT, DIV_LONG_2ADDR, DIV_LONG,
+        DOUBLE_TO_FLOAT, DOUBLE_TO_INT, DOUBLE_TO_LONG,
+        FLOAT_TO_DOUBLE, FLOAT_TO_INT, FLOAT_TO_LONG,
+        INT_TO_BYTE, INT_TO_CHAR, INT_TO_DOUBLE, INT_TO_FLOAT, INT_TO_LONG, INT_TO_SHORT,
+        LONG_TO_DOUBLE, LONG_TO_FLOAT, LONG_TO_INT,
+        MUL_DOUBLE_2ADDR, MUL_DOUBLE, MUL_FLOAT_2ADDR, MUL_FLOAT, MUL_INT_2ADDR,
+        MUL_INT_LIT16, MUL_INT_LIT8, MUL_INT, MUL_LONG_2ADDR, MUL_LONG,
+        NEG_DOUBLE, NEG_FLOAT, NEG_INT, NEG_LONG,
+        NOT_INT, NOT_LONG,
+        OR_INT_2ADDR, OR_INT_LIT16, OR_INT_LIT8, OR_INT, OR_LONG_2ADDR, OR_LONG,
+        REM_DOUBLE_2ADDR, REM_DOUBLE, REM_FLOAT_2ADDR, REM_FLOAT, REM_INT_2ADDR,
+        REM_INT_LIT16, REM_INT_LIT8, REM_INT, REM_LONG_2ADDR, REM_LONG,
+        RSUB_INT_LIT8, RSUB_INT,
+        SHL_INT_2ADDR, SHL_INT_LIT8, SHL_INT, SHL_LONG_2ADDR, SHL_LONG,
+        SHR_INT_2ADDR, SHR_INT_LIT8, SHR_INT, SHR_LONG_2ADDR, SHR_LONG,
+        SUB_DOUBLE_2ADDR, SUB_DOUBLE, SUB_FLOAT_2ADDR, SUB_FLOAT, SUB_INT_2ADDR,
+        SUB_INT, SUB_LONG_2ADDR, SUB_LONG,
+        USHR_INT_2ADDR, USHR_INT_LIT8, USHR_INT, USHR_LONG_2ADDR, USHR_LONG,
+        XOR_INT_2ADDR, XOR_INT_LIT16, XOR_INT_LIT8, XOR_INT, XOR_LONG_2ADDR, XOR_LONG,
     )
 
     val branchOpcodes = EnumSet.of(
         GOTO, GOTO_16, GOTO_32,
         IF_EQ, IF_NE, IF_LT, IF_GE, IF_GT, IF_LE,
         IF_EQZ, IF_NEZ, IF_LTZ, IF_GEZ, IF_GTZ, IF_LEZ,
+        PACKED_SWITCH_PAYLOAD, SPARSE_SWITCH_PAYLOAD
     )
 
     val returnOpcodes = EnumSet.of(
-        RETURN_VOID, RETURN, RETURN_WIDE, RETURN_OBJECT,
+        RETURN_VOID, RETURN, RETURN_WIDE, RETURN_OBJECT, RETURN_VOID_NO_BARRIER,
+        THROW
     )
 
     // Highest 4-bit register available, exclusive. Ideally return a free register less than this.
@@ -94,9 +126,13 @@ internal fun Method.findFreeRegister(startIndex: Int, vararg registersToExclude:
 
     for (i in startIndex until instructions.count()) {
         val instruction = getInstruction(i)
+        val instructionRegisters = instruction.getRegistersUsed()
 
         if (instruction.opcode in returnOpcodes) {
-            // Method returns. Use lowest register that hasn't been encountered.
+            // Method returns.
+            usedRegisters.addAll(instructionRegisters)
+
+            // Use lowest register that hasn't been encountered.
             val freeRegister = (0 until implementation!!.registerCount).find {
                 it !in usedRegisters
             }
@@ -122,26 +158,32 @@ internal fun Method.findFreeRegister(startIndex: Int, vararg registersToExclude:
         }
 
         if (instruction.opcode in writeOpcodes) {
-            val freeRegister = instruction.getRegisterWritten()
-            if (freeRegister !in usedRegisters) {
-                if (freeRegister < maxRegister4Bits) {
-                    // Found an ideal register.
-                    return freeRegister
-                }
+            val writeRegister = instruction.getRegisterWritten()
 
-                // Continue searching for a 4-bit register if available.
-                if (bestFreeRegisterFound == null || freeRegister < bestFreeRegisterFound) {
-                    bestFreeRegisterFound = freeRegister
+            if (writeRegister !in usedRegisters) {
+                // Verify the register is only used for write and not also as a parameter.
+                // If the instruction uses the write register once then it's not also a read register.
+                if (instructionRegisters.count { register -> register == writeRegister } == 1) {
+                    if (writeRegister < maxRegister4Bits) {
+                        // Found an ideal register.
+                        return writeRegister
+                    }
+
+                    // Continue searching for a 4-bit register if available.
+                    if (bestFreeRegisterFound == null || writeRegister < bestFreeRegisterFound) {
+                        bestFreeRegisterFound = writeRegister
+                    }
                 }
             }
         }
 
-        usedRegisters.addAll(instruction.getRegistersUsed())
+        usedRegisters.addAll(instructionRegisters)
     }
 
-    // Cannot be reached since a branch or return statement will
-    // be encountered before the end of the method.
-    throw IllegalStateException()
+    // Some methods can have array payloads at the end of the method after a return statement.
+    // But in normal usage this cannot be reached since a branch or return statement
+    // will be encountered before the end of the method.
+    throw IllegalArgumentException("Start index is outside the range of normal control flow: $startIndex")
 }