[WinEH] Add and use hasEHPadSuccessor instead of getLandingPadSuccessor

getLandingPadSuccessor assumes that each invoke can have at most one EH
pad successor, but WinEH invokes can have more than one. Two out of
three callers of getLandingPadSuccessor don't use the returned
landingpad, so we can make them use this simple predicate instead.

Eventually we'll have to circle back and fix SplitKit.cpp so that
register allocation works. Baby steps.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247904 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/MachineBasicBlock.h b/include/llvm/CodeGen/MachineBasicBlock.h
index 4124a836571977a494b1009a549fbc2bf9ccfbc7..c29055d0889ea288cfbd9ae908d1cd818d7af3da 100644 (file)
--- a/include/llvm/CodeGen/MachineBasicBlock.h
+++ b/include/llvm/CodeGen/MachineBasicBlock.h
@@ -381,6 +381,8 @@ public:
   /// return NULL.
   const MachineBasicBlock *getLandingPadSuccessor() const;
 
+  bool hasEHPadSuccessor() const;
+
   /// Returns true if this is the entry block of an EH funclet.
   bool isEHFuncletEntry() const { return IsEHFuncletEntry; }
 

diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index f990e10086431173b017c85a6171942b3440c648..2ef8889091f1eeb1cd380917608352bf4c48ca4d 100644 (file)
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -976,7 +976,7 @@ bool BranchFolder::TailMergeBlocks(MachineFunction &MF) {
         continue;
 
       // Skip blocks which may jump to a landing pad. Can't tail merge these.
-      if (PBB->getLandingPadSuccessor())
+      if (PBB->hasEHPadSuccessor())
         continue;
 
       MachineBasicBlock *TBB = nullptr, *FBB = nullptr;

diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index a968ab9514611b417f247fc3cf4ce0f2fbba68a5..e4d6e66b6e71ce902fafbffab75f240fc894ce84 100644 (file)
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -208,6 +208,13 @@ const MachineBasicBlock *MachineBasicBlock::getLandingPadSuccessor() const {
   return nullptr;
 }
 
+bool MachineBasicBlock::hasEHPadSuccessor() const {
+  for (const_succ_iterator I = succ_begin(), E = succ_end(); I != E; ++I)
+    if ((*I)->isEHPad())
+      return true;
+  return false;
+}
+
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 void MachineBasicBlock::dump() const {
   print(dbgs());

diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index dab1dfe4f1f856bcafe05deb5db7097b16a954ee..d06a316ba6cce2696c89408d49414d283ed029eb 100644 (file)
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -56,6 +56,7 @@ void SplitAnalysis::clear() {
 
 SlotIndex SplitAnalysis::computeLastSplitPoint(unsigned Num) {
   const MachineBasicBlock *MBB = MF.getBlockNumbered(Num);
+  // FIXME: Handle multiple EH pad successors.
   const MachineBasicBlock *LPad = MBB->getLandingPadSuccessor();
   std::pair<SlotIndex, SlotIndex> &LSP = LastSplitPoint[Num];
   SlotIndex MBBEnd = LIS.getMBBEndIdx(MBB);

diff --git a/lib/CodeGen/TailDuplication.cpp b/lib/CodeGen/TailDuplication.cpp
index 4a71c668623f37a89a64499fb976a1713fc80fa1..0a35daa535cf5dce7d7dc1f44acc6acf704af1b2 100644 (file)
--- a/lib/CodeGen/TailDuplication.cpp
+++ b/lib/CodeGen/TailDuplication.cpp
@@ -673,7 +673,7 @@ TailDuplicatePass::duplicateSimpleBB(MachineBasicBlock *TailBB,
        PE = Preds.end(); PI != PE; ++PI) {
     MachineBasicBlock *PredBB = *PI;
 
-    if (PredBB->getLandingPadSuccessor())
+    if (PredBB->hasEHPadSuccessor())
       continue;
 
     if (bothUsedInPHI(*PredBB, Succs))

diff --git a/test/CodeGen/X86/tail-merge-wineh.ll b/test/CodeGen/X86/tail-merge-wineh.ll
new file mode 100644 (file)
index 0000000..03cc9a8
--- /dev/null
+++ b/test/CodeGen/X86/tail-merge-wineh.ll
@@ -0,0 +1,116 @@
+; RUN: llc < %s | FileCheck %s
+
+; Started from this code:
+; void f() {
+;   try {
+;     try {
+;       throw 42;
+;     } catch (int) {
+;     }
+;     try {
+;       throw 42;
+;     } catch (int) {
+;     }
+;   } catch (int) {
+;   }
+; }
+
+; Don't tail merge the calls.
+; CHECK: calll _CxxThrowException
+; CHECK: calll _CxxThrowException
+
+; ModuleID = 'cppeh-pingpong.cpp'
+target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
+target triple = "i686-pc-windows-msvc"
+
+%rtti.TypeDescriptor2 = type { i8**, i8*, [3 x i8] }
+%eh.CatchableType = type { i32, i8*, i32, i32, i32, i32, i8* }
+%eh.CatchableTypeArray.1 = type { i32, [1 x %eh.CatchableType*] }
+%eh.ThrowInfo = type { i32, i8*, i8*, i8* }
+
+$"\01??_R0H@8" = comdat any
+
+$"_CT??_R0H@84" = comdat any
+
+$_CTA1H = comdat any
+
+$_TI1H = comdat any
+
+@"\01??_7type_info@@6B@" = external constant i8*
+@"\01??_R0H@8" = linkonce_odr global %rtti.TypeDescriptor2 { i8** @"\01??_7type_info@@6B@", i8* null, [3 x i8] c".H\00" }, comdat
+@"_CT??_R0H@84" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 1, i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0H@8" to i8*), i32 0, i32 -1, i32 0, i32 4, i8* null }, section ".xdata", comdat
+@_CTA1H = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.1 { i32 1, [1 x %eh.CatchableType*] [%eh.CatchableType* @"_CT??_R0H@84"] }, section ".xdata", comdat
+@_TI1H = linkonce_odr unnamed_addr constant %eh.ThrowInfo { i32 0, i8* null, i8* null, i8* bitcast (%eh.CatchableTypeArray.1* @_CTA1H to i8*) }, section ".xdata", comdat
+
+define void @"\01?f@@YAXXZ"() #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+entry:
+  %i = alloca i32, align 4
+  %tmp = alloca i32, align 4
+  %tmp1 = alloca i32, align 4
+  store i32 0, i32* %i, align 4
+  store i32 42, i32* %tmp, align 4
+  %0 = bitcast i32* %tmp to i8*
+  invoke void @_CxxThrowException(i8* %0, %eh.ThrowInfo* @_TI1H) #1
+          to label %unreachable unwind label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %entry
+  %1 = catchpad [%rtti.TypeDescriptor2* @"\01??_R0H@8", i32 0, i8* null]
+          to label %catch unwind label %catchendblock
+
+catch:                                            ; preds = %catch.dispatch
+  catchret %1 to label %catchret.dest
+
+catchret.dest:                                    ; preds = %catch
+  br label %try.cont
+
+try.cont:                                         ; preds = %catchret.dest
+  store i32 42, i32* %tmp1, align 4
+  %2 = bitcast i32* %tmp1 to i8*
+  invoke void @_CxxThrowException(i8* %2, %eh.ThrowInfo* @_TI1H) #1
+          to label %unreachable unwind label %catch.dispatch.2
+
+catch.dispatch.2:                                 ; preds = %try.cont
+  %3 = catchpad [%rtti.TypeDescriptor2* @"\01??_R0H@8", i32 0, i8* null]
+          to label %catch.4 unwind label %catchendblock.3
+
+catch.4:                                          ; preds = %catch.dispatch.2
+  catchret %3 to label %catchret.dest.5
+
+catchret.dest.5:                                  ; preds = %catch.4
+  br label %try.cont.6
+
+try.cont.6:                                       ; preds = %catchret.dest.5
+  br label %try.cont.11
+
+catchendblock.3:                                  ; preds = %catch.dispatch.2
+  catchendpad unwind label %catch.dispatch.7
+
+catch.dispatch.7:                                 ; preds = %catchendblock.3, %catchendblock
+  %4 = catchpad [%rtti.TypeDescriptor2* @"\01??_R0H@8", i32 0, i8* null]
+          to label %catch.9 unwind label %catchendblock.8
+
+catch.9:                                          ; preds = %catch.dispatch.7
+  catchret %4 to label %catchret.dest.10
+
+catchret.dest.10:                                 ; preds = %catch.9
+  br label %try.cont.11
+
+try.cont.11:                                      ; preds = %catchret.dest.10, %try.cont.6
+  ret void
+
+catchendblock.8:                                  ; preds = %catch.dispatch.7
+  catchendpad unwind to caller
+
+catchendblock:                                    ; preds = %catch.dispatch
+  catchendpad unwind label %catch.dispatch.7
+
+unreachable:                                      ; preds = %try.cont, %entry
+  unreachable
+}
+
+declare x86_stdcallcc void @_CxxThrowException(i8*, %eh.ThrowInfo*)
+
+declare i32 @__CxxFrameHandler3(...)
+
+attributes #0 = { "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { noreturn }