[WebAssembly] Add WebAssemblyLateEHPrepare pass

Summary:
Add WebAssemblyLateEHPrepare pass that does several small jobs for
exception handling. This runs before CFGSort, and is different from
WasmEHPrepare pass that runs before ISel, even though the names are
similar.

Reviewers: dschuff, majnemer

Subscribers: sbc100, jgravelle-google, sunfish, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D46803

llvm-svn: 335438

1 files changed, 74 insertions, 5 deletions

diff --git a/llvm/test/CodeGen/WebAssembly/exception.ll b/llvm/test/CodeGen/WebAssembly/exception.ll
index c4d4a6a1d89..c5e2975466d 100644
--- a/llvm/test/CodeGen/WebAssembly/exception.ll
+++ b/llvm/test/CodeGen/WebAssembly/exception.ll
@@ -17,7 +17,7 @@ define void @test_throw() {
   ret void
 }
 
-; CHECK-LABEL: test_catch:
+; CHECK-LABEL: test_catch_rethrow:
 ; CHECK:   call      foo@FUNCTION
 ; CHECK:   i32.catch     $push{{.+}}=, 0
 ; CHECK-DAG:   i32.store  __wasm_lpad_context
@@ -26,7 +26,8 @@ define void @test_throw() {
 ; CHECK:   i32.call  $push{{.+}}=, __cxa_begin_catch@FUNCTION
 ; CHECK:   call      __cxa_end_catch@FUNCTION
 ; CHECK:   call      __cxa_rethrow@FUNCTION
-define void @test_catch() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
+; CHECK-NEXT:   rethrow
+define void @test_catch_rethrow() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
 entry:
   invoke void @foo()
           to label %try.cont unwind label %catch.dispatch
@@ -57,9 +58,9 @@ try.cont:                                         ; preds = %entry, %catch
 
 ; CHECK-LABEL: test_cleanup:
 ; CHECK:   call      foo@FUNCTION
-; CHECK:   return
+; CHECK:   catch_all
 ; CHECK:   i32.call  $push20=, _ZN7CleanupD1Ev@FUNCTION
-; CHECK:   rethrow   0
+; CHECK:   rethrow
 define void @test_cleanup() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
 entry:
   %c = alloca %struct.Cleanup, align 1
@@ -76,8 +77,75 @@ ehcleanup:                                        ; preds = %entry
   cleanupret from %0 unwind to caller
 }
 
+; - Tests multple terminate pads are merged into one
+; - Tests a catch_all terminate pad is created after a catch terminate pad
+
+; CHECK-LABEL: test_terminatepad
+; CHECK:  i32.catch
+; CHECK:  call      __clang_call_terminate@FUNCTION
+; CHECK:  unreachable
+; CHECK:  catch_all
+; CHECK:  call      _ZSt9terminatev@FUNCTION
+; CHECK-NOT:  call      __clang_call_terminate@FUNCTION
+define hidden i32 @test_terminatepad() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
+entry:
+  %c = alloca %struct.Cleanup, align 1
+  %c1 = alloca %struct.Cleanup, align 1
+  invoke void @foo()
+          to label %invoke.cont unwind label %ehcleanup
+
+invoke.cont:                                      ; preds = %entry
+  %call = invoke %struct.Cleanup* @_ZN7CleanupD1Ev(%struct.Cleanup* %c1)
+          to label %try.cont unwind label %catch.dispatch
+
+ehcleanup:                                        ; preds = %entry
+  %0 = cleanuppad within none []
+  %call4 = invoke %struct.Cleanup* @_ZN7CleanupD1Ev(%struct.Cleanup* %c1) [ "funclet"(token %0) ]
+          to label %invoke.cont3 unwind label %terminate
+
+invoke.cont3:                                     ; preds = %ehcleanup
+  cleanupret from %0 unwind label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %invoke.cont3, %invoke.cont
+  %1 = catchswitch within none [label %catch.start] unwind label %ehcleanup7
+
+catch.start:                                      ; preds = %catch.dispatch
+  %2 = catchpad within %1 [i8* null]
+  %3 = call i8* @llvm.wasm.get.exception(token %2)
+  %4 = call i32 @llvm.wasm.get.ehselector(token %2)
+  %5 = call i8* @__cxa_begin_catch(i8* %3) [ "funclet"(token %2) ]
+  invoke void @__cxa_end_catch() [ "funclet"(token %2) ]
+          to label %invoke.cont5 unwind label %ehcleanup7
+
+invoke.cont5:                                     ; preds = %catch.start
+  catchret from %2 to label %try.cont
+
+try.cont:                                         ; preds = %invoke.cont5, %invoke.cont
+  %call6 = call %struct.Cleanup* @_ZN7CleanupD1Ev(%struct.Cleanup* %c)
+  ret i32 0
+
+ehcleanup7:                                       ; preds = %catch.start, %catch.dispatch
+  %6 = cleanuppad within none []
+  %call9 = invoke %struct.Cleanup* @_ZN7CleanupD1Ev(%struct.Cleanup* %c) [ "funclet"(token %6) ]
+          to label %invoke.cont8 unwind label %terminate10
+
+invoke.cont8:                                     ; preds = %ehcleanup7
+  cleanupret from %6 unwind to caller
+
+terminate:                                        ; preds = %ehcleanup
+  %7 = cleanuppad within %0 []
+  %8 = call i8* @llvm.wasm.get.exception(token %7)
+  call void @__clang_call_terminate(i8* %8) [ "funclet"(token %7) ]
+  unreachable
+
+terminate10:                                      ; preds = %ehcleanup7
+  %9 = cleanuppad within %6 []
+  %10 = call i8* @llvm.wasm.get.exception(token %9)
+  call void @__clang_call_terminate(i8* %10) [ "funclet"(token %9) ]
+  unreachable
+}
+
 declare void @foo()
-declare void @func(i32)
 declare i32 @__gxx_wasm_personality_v0(...)
 declare i8* @llvm.wasm.get.exception(token)
 declare i32 @llvm.wasm.get.ehselector(token)
@@ -86,4 +154,5 @@ declare i8* @__cxa_begin_catch(i8*)
 declare void @__cxa_end_catch()
 declare void @__cxa_rethrow()
 declare void @__clang_call_terminate(i8*)
+declare void @_ZSt9terminatev()
 declare %struct.Cleanup* @_ZN7CleanupD1Ev(%struct.Cleanup* returned)