[llvm] r297197 - SjLjEHPrepare: Fix the pass for swifterror arguments

[Arnold Schwaighofer via llvm-commits]

Author: arnolds
Date: Tue Mar  7 14:29:02 2017
New Revision: 297197

URL: http://llvm.org/viewvc/llvm-project?rev=297197&view=rev
Log:
SjLjEHPrepare: Fix the pass for swifterror arguments

We cannot leave the identity copies 'select true, arg, undef' that this pass
inserts for arguments to simplify handling of values on swifterror arguments.

swifterror arguments have restrictions on their uses.

rdar://30839288

Added:
    llvm/trunk/test/CodeGen/ARM/sjljeh-swifterror.ll
Modified:
    llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp

Modified: llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp?rev=297197&r1=297196&r2=297197&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp (original)
+++ llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp Tue Mar  7 14:29:02 2017
@@ -64,6 +64,7 @@ public:
 
 private:
   bool setupEntryBlockAndCallSites(Function &F);
+  bool undoSwiftErrorSelect(Function &F);
   void substituteLPadValues(LandingPadInst *LPI, Value *ExnVal, Value *SelVal);
   Value *setupFunctionContext(Function &F, ArrayRef<LandingPadInst *> LPads);
   void lowerIncomingArguments(Function &F);
@@ -458,6 +459,25 @@ bool SjLjEHPrepare::setupEntryBlockAndCa
   return true;
 }
 
+bool SjLjEHPrepare::undoSwiftErrorSelect(Function &F) {
+  // We have inserted dummy copies 'select true, arg, undef' in the entry block
+  // for arguments to simplify this pass.
+  // swifterror arguments cannot be used in this way. Undo the select for the
+  // swifterror argument.
+  for (auto &AI : F.args()) {
+    if (AI.isSwiftError()) {
+      assert(AI.hasOneUse() && "Must have converted the argument to a select");
+      auto *Select = dyn_cast<SelectInst>(AI.use_begin()->getUser());
+      assert(Select && "There must be single select user");
+      auto *OrigSwiftError = cast<Argument>(Select->getTrueValue());
+      Select->replaceAllUsesWith(OrigSwiftError);
+      Select->eraseFromParent();
+      return true;
+    }
+  }
+  return false;
+}
+
 bool SjLjEHPrepare::runOnFunction(Function &F) {
   Module &M = *F.getParent();
   RegisterFn = M.getOrInsertFunction(
@@ -476,5 +496,7 @@ bool SjLjEHPrepare::runOnFunction(Functi
   FuncCtxFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_functioncontext);
 
   bool Res = setupEntryBlockAndCallSites(F);
+  if (Res)
+    Res |= undoSwiftErrorSelect(F);
   return Res;
 }

Added: llvm/trunk/test/CodeGen/ARM/sjljeh-swifterror.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/sjljeh-swifterror.ll?rev=297197&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/sjljeh-swifterror.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/sjljeh-swifterror.ll Tue Mar  7 14:29:02 2017
@@ -0,0 +1,27 @@
+; RUN: opt -sjljehprepare -verify < %s | FileCheck %s
+target datalayout = "e-m:o-p:32:32-f64:32:64-v64:32:64-v128:32:128-a:0:32-n32-S32"
+target triple = "armv7s-apple-ios7.0"
+
+%swift.error = type opaque
+
+declare void @objc_msgSend() local_unnamed_addr
+
+declare i32 @__objc_personality_v0(...)
+
+; Make sure we don't leave a select on a swifterror argument.
+; CHECK-LABEL; @test
+; CHECK-NOT: select true, %0
+define swiftcc void @test(%swift.error** swifterror) local_unnamed_addr personality i32 (...)* @__objc_personality_v0 {
+entry:
+  %call28.i = invoke i32 bitcast (void ()* @objc_msgSend to i32 (i8*, i8*)*)(i8* undef, i8* undef)
+          to label %invoke.cont.i unwind label %lpad.i
+
+invoke.cont.i:
+  unreachable
+
+lpad.i:
+  %1 = landingpad { i8*, i32 }
+          cleanup
+  resume { i8*, i32 } undef
+}
+