From ebc3b25e187cb39a12dcb05ae1c44de23aa5696e Mon Sep 17 00:00:00 2001
From: Nicolas Geoffray <ngeoffray@google.com>
Date: Wed, 9 Jan 2019 10:47:02 +0000
Subject: Fix compiler bug when typing exceptions.

Handlers of different exception types can start at the same
bytecode address, so we should update the type in the compiler
to avoid wrongly typing the exception.

bug: 119944057
Test: 689-multi-catch
Change-Id: I66e43890634965ee7790436c8e5a718564c6040f
---
 compiler/optimizing/block_builder.cc              | 12 ++++++++++--
 compiler/optimizing/nodes.h                       | 12 ++++++++----
 compiler/optimizing/reference_type_propagation.cc |  8 ++++----
 3 files changed, 22 insertions(+), 10 deletions(-)

(limited to 'compiler/optimizing')

diff --git a/compiler/optimizing/block_builder.cc b/compiler/optimizing/block_builder.cc
index 3672cce4c5..a5f78cafe0 100644
--- a/compiler/optimizing/block_builder.cc
+++ b/compiler/optimizing/block_builder.cc
@@ -315,8 +315,16 @@ void HBasicBlockBuilder::InsertTryBoundaryBlocks() {
     CatchHandlerIterator iterator(handlers_ptr);
     for (; iterator.HasNext(); iterator.Next()) {
       uint32_t address = iterator.GetHandlerAddress();
-      if (catch_blocks.find(address) != catch_blocks.end()) {
+      auto existing = catch_blocks.find(address);
+      if (existing != catch_blocks.end()) {
         // Catch block already processed.
+        TryCatchInformation* info = existing->second->GetTryCatchInformation();
+        if (iterator.GetHandlerTypeIndex() != info->GetCatchTypeIndex()) {
+          // The handler is for multiple types. We could record all the types, but
+          // doing class resolution here isn't ideal, and it's unclear whether wasting
+          // the space in TryCatchInformation is worth it.
+          info->SetInvalidTypeIndex();
+        }
         continue;
       }
 
@@ -337,7 +345,7 @@ void HBasicBlockBuilder::InsertTryBoundaryBlocks() {
 
       catch_blocks.Put(address, catch_block);
       catch_block->SetTryCatchInformation(
-        new (allocator_) TryCatchInformation(iterator.GetHandlerTypeIndex(), *dex_file_));
+          new (allocator_) TryCatchInformation(iterator.GetHandlerTypeIndex(), *dex_file_));
     }
     handlers_ptr = iterator.EndDataPointer();
   }
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 686a2deb0b..48fb611da2 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -895,7 +895,7 @@ class TryCatchInformation : public ArenaObject<kArenaAllocTryCatchInfo> {
   explicit TryCatchInformation(const HTryBoundary& try_entry)
       : try_entry_(&try_entry),
         catch_dex_file_(nullptr),
-        catch_type_index_(DexFile::kDexNoIndex16) {
+        catch_type_index_(dex::TypeIndex::Invalid()) {
     DCHECK(try_entry_ != nullptr);
   }
 
@@ -914,9 +914,9 @@ class TryCatchInformation : public ArenaObject<kArenaAllocTryCatchInfo> {
 
   bool IsCatchBlock() const { return catch_dex_file_ != nullptr; }
 
-  bool IsCatchAllTypeIndex() const {
+  bool IsValidTypeIndex() const {
     DCHECK(IsCatchBlock());
-    return !catch_type_index_.IsValid();
+    return catch_type_index_.IsValid();
   }
 
   dex::TypeIndex GetCatchTypeIndex() const {
@@ -929,6 +929,10 @@ class TryCatchInformation : public ArenaObject<kArenaAllocTryCatchInfo> {
     return *catch_dex_file_;
   }
 
+  void SetInvalidTypeIndex() {
+    catch_type_index_ = dex::TypeIndex::Invalid();
+  }
+
  private:
   // One of possibly several TryBoundary instructions entering the block's try.
   // Only set for try blocks.
@@ -936,7 +940,7 @@ class TryCatchInformation : public ArenaObject<kArenaAllocTryCatchInfo> {
 
   // Exception type information. Only set for catch blocks.
   const DexFile* catch_dex_file_;
-  const dex::TypeIndex catch_type_index_;
+  dex::TypeIndex catch_type_index_;
 };
 
 static constexpr size_t kNoLifetime = -1;
diff --git a/compiler/optimizing/reference_type_propagation.cc b/compiler/optimizing/reference_type_propagation.cc
index 61e7a60ea9..4929e0a3a1 100644
--- a/compiler/optimizing/reference_type_propagation.cc
+++ b/compiler/optimizing/reference_type_propagation.cc
@@ -699,14 +699,14 @@ void ReferenceTypePropagation::RTPVisitor::VisitLoadException(HLoadException* in
   DCHECK(instr->GetBlock()->IsCatchBlock());
   TryCatchInformation* catch_info = instr->GetBlock()->GetTryCatchInformation();
 
-  if (catch_info->IsCatchAllTypeIndex()) {
-    instr->SetReferenceTypeInfo(
-        ReferenceTypeInfo::Create(handle_cache_->GetThrowableClassHandle(), /* is_exact= */ false));
-  } else {
+  if (catch_info->IsValidTypeIndex()) {
     UpdateReferenceTypeInfo(instr,
                             catch_info->GetCatchTypeIndex(),
                             catch_info->GetCatchDexFile(),
                             /* is_exact= */ false);
+  } else {
+    instr->SetReferenceTypeInfo(
+        ReferenceTypeInfo::Create(handle_cache_->GetThrowableClassHandle(), /* is_exact= */ false));
   }
 }
 
-- 
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