[WinEH] Add a funclet layout pass
Windows EH funclets need to be contiguous. The FuncletLayout pass will
ensure that the funclets are together and begin with a funclet entry MBB.
Differential Revision: http://reviews.llvm.org/D12943
llvm-svn: 247937
diff --git a/llvm/include/llvm/CodeGen/Passes.h b/llvm/include/llvm/CodeGen/Passes.h
index 13108d9..b06c576 100644
--- a/llvm/include/llvm/CodeGen/Passes.h
+++ b/llvm/include/llvm/CodeGen/Passes.h
@@ -582,6 +582,9 @@
/// StackSlotColoring - This pass performs stack slot coloring.
extern char &StackSlotColoringID;
+ /// \brief This pass lays out funclets contiguously.
+ extern char &FuncletLayoutID;
+
/// createStackProtectorPass - This pass adds stack protectors to functions.
///
FunctionPass *createStackProtectorPass(const TargetMachine *TM);
diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index dc5c25c..2b03759 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -299,6 +299,7 @@
void initializeLoopDistributePass(PassRegistry&);
void initializeSjLjEHPreparePass(PassRegistry&);
void initializeDemandedBitsPass(PassRegistry&);
+void initializeFuncletLayoutPass(PassRegistry &);
}
#endif
diff --git a/llvm/lib/CodeGen/CMakeLists.txt b/llvm/lib/CodeGen/CMakeLists.txt
index b2a1efc..9c63dc7a0 100644
--- a/llvm/lib/CodeGen/CMakeLists.txt
+++ b/llvm/lib/CodeGen/CMakeLists.txt
@@ -26,6 +26,7 @@
ExpandISelPseudos.cpp
ExpandPostRAPseudos.cpp
FaultMaps.cpp
+ FuncletLayout.cpp
GCMetadata.cpp
GCMetadataPrinter.cpp
GCRootLowering.cpp
diff --git a/llvm/lib/CodeGen/CodeGen.cpp b/llvm/lib/CodeGen/CodeGen.cpp
index 155c5ec..7d18058 100644
--- a/llvm/lib/CodeGen/CodeGen.cpp
+++ b/llvm/lib/CodeGen/CodeGen.cpp
@@ -29,6 +29,7 @@
initializeExpandISelPseudosPass(Registry);
initializeExpandPostRAPass(Registry);
initializeFinalizeMachineBundlesPass(Registry);
+ initializeFuncletLayoutPass(Registry);
initializeGCMachineCodeAnalysisPass(Registry);
initializeGCModuleInfoPass(Registry);
initializeIfConverterPass(Registry);
diff --git a/llvm/lib/CodeGen/FuncletLayout.cpp b/llvm/lib/CodeGen/FuncletLayout.cpp
new file mode 100644
index 0000000..9b40a1a
--- /dev/null
+++ b/llvm/lib/CodeGen/FuncletLayout.cpp
@@ -0,0 +1,97 @@
+//===-- FuncletLayout.cpp - Contiguously lay out funclets -----------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements basic block placement transformations which result in
+// funclets being contiguous.
+//
+//===----------------------------------------------------------------------===//
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/ADT/MapVector.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "funclet-layout"
+
+namespace {
+class FuncletLayout : public MachineFunctionPass {
+public:
+ static char ID; // Pass identification, replacement for typeid
+ FuncletLayout() : MachineFunctionPass(ID) {
+ initializeFuncletLayoutPass(*PassRegistry::getPassRegistry());
+ }
+
+ bool runOnMachineFunction(MachineFunction &F) override;
+};
+}
+
+static void
+collectFuncletMembers(MapVector<MachineBasicBlock *, int> &FuncletMembership,
+ int Funclet, MachineBasicBlock *MBB) {
+ // Don't revisit blocks.
+ if (FuncletMembership.count(MBB) > 0)
+ return;
+
+ // Add this MBB to our funclet.
+ FuncletMembership[MBB] = Funclet;
+
+ bool IsReturn = false;
+ int NumTerminators = 0;
+ for (MachineInstr &MI : MBB->terminators()) {
+ IsReturn |= MI.isReturn();
+ ++NumTerminators;
+ }
+ assert((!IsReturn || NumTerminators == 1) &&
+ "Expected only one terminator when a return is present!");
+
+ // Returns are boundaries where funclet transfer can occur, don't follow
+ // successors.
+ if (IsReturn)
+ return;
+
+ for (MachineBasicBlock *SMBB : MBB->successors())
+ if (!SMBB->isEHPad())
+ collectFuncletMembers(FuncletMembership, Funclet, SMBB);
+}
+
+char FuncletLayout::ID = 0;
+char &llvm::FuncletLayoutID = FuncletLayout::ID;
+INITIALIZE_PASS(FuncletLayout, "funclet-layout",
+ "Contiguously Lay Out Funclets", false, false)
+
+bool FuncletLayout::runOnMachineFunction(MachineFunction &F) {
+ // We don't have anything to do if there aren't any EH pads.
+ if (!F.getMMI().hasEHFunclets())
+ return false;
+
+ SmallVector<MachineBasicBlock *, 16> FuncletBlocks;
+ for (MachineBasicBlock &MBB : F)
+ if (MBB.isEHFuncletEntry())
+ FuncletBlocks.push_back(&MBB);
+
+ // We don't have anything to do if there aren't any EH pads.
+ if (FuncletBlocks.empty())
+ return false;
+
+ MapVector<MachineBasicBlock *, int> FuncletMembership;
+ for (MachineBasicBlock *MBB : FuncletBlocks)
+ collectFuncletMembers(FuncletMembership, MBB->getNumber(), MBB);
+
+ for (std::pair<llvm::MachineBasicBlock *, int> &FuncletMember :
+ FuncletMembership) {
+ // Move this block to the end of the function.
+ MachineBasicBlock *MBB = FuncletMember.first;
+ MBB->moveAfter(--F.end());
+ }
+
+ // Conservatively assume we changed something.
+ return true;
+}
diff --git a/llvm/lib/CodeGen/Passes.cpp b/llvm/lib/CodeGen/Passes.cpp
index ee559e6..7ea7b6e 100644
--- a/llvm/lib/CodeGen/Passes.cpp
+++ b/llvm/lib/CodeGen/Passes.cpp
@@ -582,6 +582,8 @@
addPreEmitPass();
+ addPass(&FuncletLayoutID, false);
+
addPass(&StackMapLivenessID, false);
AddingMachinePasses = false;
diff --git a/llvm/test/CodeGen/X86/funclet-layout.ll b/llvm/test/CodeGen/X86/funclet-layout.ll
new file mode 100644
index 0000000..9e6fbb6
--- /dev/null
+++ b/llvm/test/CodeGen/X86/funclet-layout.ll
@@ -0,0 +1,45 @@
+; RUN: llc -mtriple=x86_64-windows-msvc < %s | FileCheck %s
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc"
+
+define void @f(i1 %B) personality i32 (...)* @__CxxFrameHandler3 {
+entry:
+ invoke void @g()
+ to label %unreachable unwind label %catch.dispatch
+
+catch.dispatch:
+ %cp = catchpad [i8* null, i32 64, i8* null]
+ to label %catch unwind label %catchendblock
+
+catch:
+ br i1 %B, label %catchret, label %catch
+
+catchret:
+ catchret %cp to label %try.cont
+
+try.cont:
+ ret void
+
+catchendblock:
+ catchendpad unwind to caller
+
+unreachable:
+ unreachable
+}
+
+; CHECK-LABEL: f:
+
+; The entry funclet contains %entry and %try.cont
+; CHECK: # %entry
+; CHECK: # %try.cont
+; CHECK: retq
+
+; The catch funclet contains %catch and %catchret
+; CHECK: # %catch
+; CHECK: # %catchret
+; CHECK: retq
+
+declare void @g()
+
+declare i32 @__CxxFrameHandler3(...)