From 37d14becd11e86c3e634055d0cfe011b51ef5622 Mon Sep 17 00:00:00 2001
From: Ben Gruver <bgruv@google.com>
Date: Wed, 14 Oct 2015 21:57:23 -0700
Subject: [PATCH] Fix register propagation when overriding a register type from
 a predecessor

---
 .../jf/dexlib2/analysis/AnalyzedInstruction.java  | 11 +++++++++--
 .../org/jf/dexlib2/analysis/MethodAnalyzer.java   | 15 +++++++--------
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/dexlib2/src/main/java/org/jf/dexlib2/analysis/AnalyzedInstruction.java b/dexlib2/src/main/java/org/jf/dexlib2/analysis/AnalyzedInstruction.java
index 1f600835..ac17db3f 100644
--- a/dexlib2/src/main/java/org/jf/dexlib2/analysis/AnalyzedInstruction.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/analysis/AnalyzedInstruction.java
@@ -189,12 +189,19 @@ public class AnalyzedInstruction implements Comparable<AnalyzedInstruction> {
      * register is a destination register for this instruction, or if the pre-instruction register type didn't change
      * after merging in the given register type
      */
-    protected boolean mergeRegister(int registerNumber, RegisterType registerType, BitSet verifiedInstructions) {
+    protected boolean mergeRegister(int registerNumber, RegisterType registerType, BitSet verifiedInstructions,
+                                    boolean override) {
         assert registerNumber >= 0 && registerNumber < postRegisterMap.length;
         assert registerType != null;
 
         RegisterType oldRegisterType = preRegisterMap[registerNumber];
-        RegisterType mergedRegisterType = oldRegisterType.merge(registerType);
+
+        RegisterType mergedRegisterType;
+        if (override) {
+            mergedRegisterType = getMergedPreRegisterTypeFromPredecessors(registerNumber);
+        } else {
+            mergedRegisterType = oldRegisterType.merge(registerType);
+        }
 
         if (mergedRegisterType.equals(oldRegisterType)) {
             return false;
diff --git a/dexlib2/src/main/java/org/jf/dexlib2/analysis/MethodAnalyzer.java b/dexlib2/src/main/java/org/jf/dexlib2/analysis/MethodAnalyzer.java
index e634297f..856060b1 100644
--- a/dexlib2/src/main/java/org/jf/dexlib2/analysis/MethodAnalyzer.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/analysis/MethodAnalyzer.java
@@ -336,8 +336,7 @@ public class MethodAnalyzer {
                 registerType);
     }
 
-    private void propagateChanges(@Nonnull BitSet changedInstructions, int registerNumber,
-                                  @Nonnull RegisterType registerType) {
+    private void propagateChanges(@Nonnull BitSet changedInstructions, int registerNumber, boolean override) {
         //Using a for loop inside the while loop optimizes for the common case of the successors of an instruction
         //occurring after the instruction. Any successors that occur prior to the instruction will be picked up on
         //the next iteration of the while loop.
@@ -350,7 +349,7 @@ public class MethodAnalyzer {
                 changedInstructions.clear(instructionIndex);
 
                 propagateRegisterToSuccessors(analyzedInstructions.valueAt(instructionIndex), registerNumber,
-                        changedInstructions);
+                        changedInstructions, override);
             }
         }
     }
@@ -366,7 +365,7 @@ public class MethodAnalyzer {
         }
         changedInstructions.set(analyzedInstruction.instructionIndex);
 
-        propagateChanges(changedInstructions, registerNumber, registerType);
+        propagateChanges(changedInstructions, registerNumber, true);
 
         if (registerType.category == RegisterType.LONG_LO) {
             checkWidePair(registerNumber, analyzedInstruction);
@@ -388,9 +387,9 @@ public class MethodAnalyzer {
             return;
         }
 
-        propagateRegisterToSuccessors(analyzedInstruction, registerNumber, changedInstructions);
+        propagateRegisterToSuccessors(analyzedInstruction, registerNumber, changedInstructions, false);
 
-        propagateChanges(changedInstructions, registerNumber, registerType);
+        propagateChanges(changedInstructions, registerNumber, false);
 
         if (registerType.category == RegisterType.LONG_LO) {
             checkWidePair(registerNumber, analyzedInstruction);
@@ -402,10 +401,10 @@ public class MethodAnalyzer {
     }
 
     private void propagateRegisterToSuccessors(@Nonnull AnalyzedInstruction instruction, int registerNumber,
-                                               @Nonnull BitSet changedInstructions) {
+                                               @Nonnull BitSet changedInstructions, boolean override) {
         RegisterType postRegisterType = instruction.getPostInstructionRegisterType(registerNumber);
         for (AnalyzedInstruction successor: instruction.successors) {
-            if (successor.mergeRegister(registerNumber, postRegisterType, analyzedState)) {
+            if (successor.mergeRegister(registerNumber, postRegisterType, analyzedState, override)) {
                 changedInstructions.set(successor.instructionIndex);
             }
         }