[WinEH] Add 32-bit SEH state table emission prototype

This gets all the handler info through to the asm printer and we can
look at the .xdata tables now. I've convinced one small catch-all test
case to work, but other than that, it would be a stretch to say this is
functional.

The state numbering algorithm avoids doing any scope reconstruction as
we do for C++ to simplify the implementation.

llvm-svn: 239433

1 files changed, 17 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/WinEHPrepare.cpp b/llvm/lib/CodeGen/WinEHPrepare.cpp
index c2b3d84ca36..6bdc9c95d61 100644
--- a/llvm/lib/CodeGen/WinEHPrepare.cpp
+++ b/llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -24,6 +24,7 @@
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/TinyPtrVector.h"
 #include "llvm/Analysis/LibCallSemantics.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/CodeGen/WinEHFuncInfo.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
@@ -124,6 +125,7 @@ private:
 
   // All fields are reset by runOnFunction.
   DominatorTree *DT = nullptr;
+  const TargetLibraryInfo *LibInfo = nullptr;
   EHPersonality Personality = EHPersonality::Unknown;
   CatchHandlerMapTy CatchHandlerMap;
   CleanupHandlerMapTy CleanupHandlerMap;
@@ -384,6 +386,7 @@ bool WinEHPrepare::runOnFunction(Function &Fn) {
     return false;
 
   DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+  LibInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
 
   // If there were any landing pads, prepareExceptionHandlers will make changes.
   prepareExceptionHandlers(Fn, LPads);
@@ -394,6 +397,7 @@ bool WinEHPrepare::doFinalization(Module &M) { return false; }
 
 void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addRequired<DominatorTreeWrapperPass>();
+  AU.addRequired<TargetLibraryInfoWrapperPass>();
 }
 
 static bool isSelectorDispatch(BasicBlock *BB, BasicBlock *&CatchHandler,
@@ -1016,10 +1020,17 @@ bool WinEHPrepare::prepareExceptionHandlers(
   Builder.CreateCall(FrameEscapeFn, AllocasToEscape);
 
   if (SEHExceptionCodeSlot) {
-    if (SEHExceptionCodeSlot->hasNUses(0))
-      SEHExceptionCodeSlot->eraseFromParent();
-    else if (isAllocaPromotable(SEHExceptionCodeSlot))
+    if (isAllocaPromotable(SEHExceptionCodeSlot)) {
+      SmallPtrSet<BasicBlock *, 4> UserBlocks;
+      for (User *U : SEHExceptionCodeSlot->users()) {
+        if (auto *Inst = dyn_cast<Instruction>(U))
+          UserBlocks.insert(Inst->getParent());
+      }
       PromoteMemToReg(SEHExceptionCodeSlot, *DT);
+      // After the promotion, kill off dead instructions.
+      for (BasicBlock *BB : UserBlocks)
+        SimplifyInstructionsInBlock(BB, LibInfo);
+    }
   }
 
   // Clean up the handler action maps we created for this function
@@ -1029,6 +1040,7 @@ bool WinEHPrepare::prepareExceptionHandlers(
   CleanupHandlerMap.clear();
   HandlerToParentFP.clear();
   DT = nullptr;
+  LibInfo = nullptr;
   SEHExceptionCodeSlot = nullptr;
   EHBlocks.clear();
   NormalBlocks.clear();
@@ -1143,7 +1155,6 @@ void WinEHPrepare::completeNestedLandingPad(Function *ParentFn,
   ++II;
   // The instruction after the landing pad should now be a call to eh.actions.
   const Instruction *Recover = II;
-  assert(match(Recover, m_Intrinsic<Intrinsic::eh_actions>()));
   const IntrinsicInst *EHActions = cast<IntrinsicInst>(Recover);
 
   // Remap the return target in the nested handler.
@@ -2454,6 +2465,8 @@ void WinEHPrepare::findCleanupHandlers(LandingPadActions &Actions,
 void llvm::parseEHActions(
     const IntrinsicInst *II,
     SmallVectorImpl<std::unique_ptr<ActionHandler>> &Actions) {
+  assert(II->getIntrinsicID() == Intrinsic::eh_actions &&
+         "attempted to parse non eh.actions intrinsic");
   for (unsigned I = 0, E = II->getNumArgOperands(); I != E;) {
     uint64_t ActionKind =
         cast<ConstantInt>(II->getArgOperand(I))->getZExtValue();
@@ -2766,7 +2779,6 @@ void WinEHNumbering::calculateStateNumbers(const Function &F) {
     auto *ActionsCall = dyn_cast<IntrinsicInst>(LPI->getNextNode());
     if (!ActionsCall)
       continue;
-    assert(ActionsCall->getIntrinsicID() == Intrinsic::eh_actions);
     parseEHActions(ActionsCall, ActionList);
     if (ActionList.empty())
       continue;