Add an environment to the beginning of catch blocks

We can use the HNop to generate an environment for us and start
using the existing environment infrastructure (e.g. EmitEnvironment)
for recording the catch block's environment.

This is done to provide support for try catch inlining since it
requires several environments rather than just the one.

When doing so, we now have a HNop at the beginning of each catch
block. We have to modify code sinking to allow it to sink code
past this HNop because if we don't we will sink code right before
this instruction which will break the invariant of that HNop being
the first instruction of a catch block.

Test: art/test/testrunner/testrunner.py --host --64 --optimizing -b
Change-Id: I16e7b8cad499fd2d6f7415112b46206db8daf544

1 files changed, 9 insertions, 0 deletions

diff --git a/compiler/optimizing/instruction_builder.cc b/compiler/optimizing/instruction_builder.cc
index 605427ba11..ba58c8d1fe 100644
--- a/compiler/optimizing/instruction_builder.cc
+++ b/compiler/optimizing/instruction_builder.cc
@@ -343,6 +343,10 @@ static bool IsBlockPopulated(HBasicBlock* block) {
     // Suspend checks were inserted into loop headers during building of dominator tree.
     DCHECK(block->GetFirstInstruction()->IsSuspendCheck());
     return block->GetFirstInstruction() != block->GetLastInstruction();
+  } else if (block->IsCatchBlock()) {
+    // Nops were inserted into the beginning of catch blocks.
+    DCHECK(block->GetFirstInstruction()->IsNop());
+    return block->GetFirstInstruction() != block->GetLastInstruction();
   } else {
     return !block->GetInstructions().IsEmpty();
   }
@@ -387,6 +391,11 @@ bool HInstructionBuilder::Build() {
       // This is slightly odd because the loop header might not be empty (TryBoundary).
       // But we're still creating the environment with locals from the top of the block.
       InsertInstructionAtTop(suspend_check);
+    } else if (current_block_->IsCatchBlock()) {
+      // We add an environment emitting instruction at the beginning of each catch block, in order
+      // to support try catch inlining.
+      // This is slightly odd because the catch block might not be empty (TryBoundary).
+      InsertInstructionAtTop(new (allocator_) HNop(block_dex_pc, /* needs_environment= */ true));
     }
 
     if (block_dex_pc == kNoDexPc || current_block_ != block_builder_->GetBlockAt(block_dex_pc)) {