[llvm] r236815 - [mips] Emit the .insn directive for empty basic blocks.

[Vasileios Kalintiris]

Author: vkalintiris
Date: Fri May  8 04:10:15 2015
New Revision: 236815

URL: http://llvm.org/viewvc/llvm-project?rev=236815&view=rev
Log:
[mips] Emit the .insn directive for empty basic blocks.

Summary:
In microMIPS, labels need to know whether they are on code or data. This is
indicated with STO_MIPS_MICROMIPS and can be inferred by being followed
by instructions. For empty basic blocks, we can ensure this by emitting the
.insn directive after the label.

Also, this fixes some failures in our out-of-tree microMIPS buildbots, for the
exception handling regression tests under: SingleSource/Regression/C++/EH

Reviewers: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9530

Added:
    llvm/trunk/test/CodeGen/Mips/insn-zero-size-bb.ll
Modified:
    llvm/trunk/lib/Target/Mips/MipsAsmPrinter.cpp
    llvm/trunk/lib/Target/Mips/MipsAsmPrinter.h

Modified: llvm/trunk/lib/Target/Mips/MipsAsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/MipsAsmPrinter.cpp?rev=236815&r1=236814&r2=236815&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/MipsAsmPrinter.cpp (original)
+++ llvm/trunk/lib/Target/Mips/MipsAsmPrinter.cpp Fri May  8 04:10:15 2015
@@ -384,6 +384,12 @@ void MipsAsmPrinter::EmitFunctionBodyEnd
   OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
 }
 
+void MipsAsmPrinter::EmitBasicBlockEnd(const MachineBasicBlock &MBB) {
+  MipsTargetStreamer &TS = getTargetStreamer();
+  if (MBB.size() == 0)
+    TS.emitDirectiveInsn();
+}
+
 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
 /// exactly one predecessor and the control transfer mechanism between
 /// the predecessor and this block is a fall-through.

Modified: llvm/trunk/lib/Target/Mips/MipsAsmPrinter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/MipsAsmPrinter.h?rev=236815&r1=236814&r2=236815&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/MipsAsmPrinter.h (original)
+++ llvm/trunk/lib/Target/Mips/MipsAsmPrinter.h Fri May  8 04:10:15 2015
@@ -124,6 +124,7 @@ public:
   void EmitFunctionEntryLabel() override;
   void EmitFunctionBodyStart() override;
   void EmitFunctionBodyEnd() override;
+  void EmitBasicBlockEnd(const MachineBasicBlock &MBB) override;
   bool isBlockOnlyReachableByFallthrough(
                                    const MachineBasicBlock* MBB) const override;
   bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,

Added: llvm/trunk/test/CodeGen/Mips/insn-zero-size-bb.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Mips/insn-zero-size-bb.ll?rev=236815&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Mips/insn-zero-size-bb.ll (added)
+++ llvm/trunk/test/CodeGen/Mips/insn-zero-size-bb.ll Fri May  8 04:10:15 2015
@@ -0,0 +1,27 @@
+; RUN: llc < %s -march=mips -mcpu=mips32 | FileCheck %s
+; RUN: llc < %s -march=mips -mcpu=mips32r3 -mattr=+micromips | FileCheck %s
+; RUN: llc < %s -march=mips -mcpu=mips16 | FileCheck %s
+
+; Verify that we emit the .insn directive for zero-sized (empty) basic blocks.
+; This only really matters for microMIPS and MIPS16.
+
+declare i32 @foo(...)
+declare void @bar()
+
+define void @main() {
+entry:
+  invoke void @bar() #0
+          to label %unreachable unwind label %return
+
+unreachable:
+; CHECK:          ${{.*}}: # %unreachable
+; CHECK-NEXT:         .insn
+  unreachable
+
+return:
+  %0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @foo to i8*)
+          catch i8* null
+  ret void
+}
+
+attributes #0 = { noreturn }