commit 9d894662426e413454935e483d56a8cc33924174
author Alexei Zavjalov <alexei.zavjalov@intel.com> Mon Apr 21 20:45:24 2014 +0700
committer Alexei Zavjalov <alexei.zavjalov@intel.com> Mon Apr 21 20:45:24 2014 +0700
tree 6ae3c812e6a56401fb98a074f77f27f4bc7ba13e
parent 86e1b5e7e2bca99dd2092eab8ced977d97830873

Skip BBs without SSA representation in the Constant Propagation phase

In some cases the constant propagation optimization may get the MIR graph
where some of the BBs have no predecessors and do not transformed to the
SSA form. If such BB has operations on constants this may lead to segfault.
This patch adds the condition that will pass the only BBs with SSA.

Change-Id: I816d46b2492c5bd4748f983c3725b4798f9ebd68
Signed-off-by: Alexei Zavjalov <alexei.zavjalov@intel.com>

compiler/dex/mir_optimization.cc

diff --git a/compiler/dex/mir_optimization.cc b/compiler/dex/mir_optimization.cc
index 51419f4..937e258 100644
--- a/compiler/dex/mir_optimization.cc
+++ b/compiler/dex/mir_optimization.cc
@@ -42,6 +42,11 @@
   MIR* mir;
 
   for (mir = bb->first_mir_insn; mir != NULL; mir = mir->next) {
+    // Skip pass if BB has MIR without SSA representation.
+    if (mir->ssa_rep == NULL) {
+       return;
+    }
+
     uint64_t df_attributes = oat_data_flow_attributes_[mir->dalvikInsn.opcode];
 
     DecodedInstruction *d_insn = &mir->dalvikInsn;

test/083-compiler-regressions/expected.txt

diff --git a/test/083-compiler-regressions/expected.txt b/test/083-compiler-regressions/expected.txt
index db50300..7576b02 100644
--- a/test/083-compiler-regressions/expected.txt
+++ b/test/083-compiler-regressions/expected.txt
@@ -16,6 +16,7 @@
 largeFrame passes
 largeFrameFloat passes
 mulBy1Test passes
+constantPropagationTest passes
 getterSetterTest passes
 identityTest passes
 wideGetterSetterTest passes

test/083-compiler-regressions/src/Main.java

diff --git a/test/083-compiler-regressions/src/Main.java b/test/083-compiler-regressions/src/Main.java
index d32c037..6a12ca9 100644
--- a/test/083-compiler-regressions/src/Main.java
+++ b/test/083-compiler-regressions/src/Main.java
@@ -38,6 +38,7 @@
         largeFrameTest();
         largeFrameTestFloat();
         mulBy1Test();
+        constantPropagationTest();
         getterSetterTest();
         identityTest();
         wideGetterSetterTest();
@@ -766,6 +767,32 @@
         }
     }
 
+    static void constantPropagationTest() {
+        int i = 1;
+        int t = 1;
+        float z = 1F;
+        long h = 1L;
+        int g[] = new int[1];
+        int w = 1;
+        long f = 0;
+
+        for (int a = 1; a < 100; a++) {
+            try {
+                i = (int)(z);
+                h >>= (0 % t);
+            }
+            finally {
+                w = (int)(2 * (f * 6));
+            }
+        }
+
+        if (w == 0 && h == 1 && g[0] == 0) {
+            System.out.println("constantPropagationTest passes");
+        } else {
+            System.out.println("constantPropagationTest fails");
+        }
+    }
+
     static void b2296099Test() throws Exception {
        int x = -1190771042;
        int dist = 360530809;