commit 7397593388d099a51cf8eaefb199f6d439dfee8b
author Ian Zerny <zerny@google.com> Tue Aug 29 07:37:47 2017 +0200
committer Ian Zerny <zerny@google.com> Tue Aug 29 07:37:47 2017 +0200
tree aeed5324d2660aa38f45ac31cb04827bf18f836f
parent efcb4ce80a38d52717aa5b06275ebf256de8f703

Ensure non-shared instruction after debug positions before shared suffix blocks.

R=ager

Bug: 65066975
Change-Id: I683aee5d86a6d552811906e10ba6ff748c75f3f7

src/main/java/com/android/tools/r8/ir/optimize/PeepholeOptimizer.java

diff --git a/src/main/java/com/android/tools/r8/ir/optimize/PeepholeOptimizer.java b/src/main/java/com/android/tools/r8/ir/optimize/PeepholeOptimizer.java
index a7d6e8d..35cadf2 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/PeepholeOptimizer.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/PeepholeOptimizer.java
@@ -84,7 +84,9 @@
             commonSuffixSize = Math.min(
                 commonSuffixSize, sharedSuffixSizeExcludingExit(firstPred, pred, allocator));
           }
-          assert commonSuffixSize >= 1;
+          if (commonSuffixSize == 0) {
+            continue;
+          }
           int blockNumber = startNumberOfNewBlock + newBlocks.size();
           BasicBlock newBlock = createAndInsertBlockForSuffix(
               blockNumber, commonSuffixSize, predsWithSameLastInstruction, block);
@@ -160,7 +162,9 @@
       Instruction i0 = it0.previous();
       Instruction i1 = it1.previous();
       if (!i0.identicalAfterRegisterAllocation(i1, allocator)) {
-        return suffixSize;
+        // If the shared suffix follows a debug position at least one instruction must remain
+        // unshared to ensure the debug position is at a different pc than the shared suffix.
+        return i0.isDebugPosition() || i1.isDebugPosition() ? suffixSize - 1 : suffixSize;
       }
       suffixSize++;
     }

src/test/debugTestResources/Locals.java

diff --git a/src/test/debugTestResources/Locals.java b/src/test/debugTestResources/Locals.java
index 56613b3..5afcabb 100644
--- a/src/test/debugTestResources/Locals.java
+++ b/src/test/debugTestResources/Locals.java
@@ -308,6 +308,16 @@
     return "OK";
   }
 
+  public static void regression65066975(boolean bit) {
+    nop();
+    if (bit) {
+      nop();
+    } else {
+      nop();
+    }
+    nop();
+  }
+
   public static void main(String[] args) {
     noLocals();
     unusedLocals();
@@ -327,5 +337,6 @@
     switchRewriteToIfs(1);
     switchRewriteToSwitches(1);
     regression65039701(true);
+    regression65066975(false);
   }
 }

src/test/java/com/android/tools/r8/debug/LocalsTest.java

diff --git a/src/test/java/com/android/tools/r8/debug/LocalsTest.java b/src/test/java/com/android/tools/r8/debug/LocalsTest.java
index 926e84a..12fd23d 100644
--- a/src/test/java/com/android/tools/r8/debug/LocalsTest.java
+++ b/src/test/java/com/android/tools/r8/debug/LocalsTest.java
@@ -546,4 +546,23 @@
         checkLine(SOURCE_FILE, 308),
         run());
   }
+
+  @Test
+  public void regression65066975() throws Throwable {
+    runDebugTest(
+        "Locals",
+        breakpoint("Locals", "regression65066975"),
+        run(),
+        checkLine(SOURCE_FILE, 312),
+        checkLocal("bit", Value.createBoolean(false)),
+        stepOver(),
+        checkLine(SOURCE_FILE, 313),
+        stepOver(),
+        checkLine(SOURCE_FILE, 316),
+        stepOver(),
+        checkLine(SOURCE_FILE, 318),
+        stepOver(),
+        checkLine(SOURCE_FILE, 319),
+        run());
+  }
 }