[WebAssembly] CFG sort support for exception handling

Summary:
This patch extends CFGSort pass to support exception handling. Once it
places a loop header, it does not place blocks that are not dominated by
the loop header until all the loop blocks are sorted. This patch extends
the same algorithm to exception 'catch' part, using the information
calculated by WebAssemblyExceptionInfo class.

Reviewers: dschuff, sunfish

Subscribers: sbc100, jgravelle-google, llvm-commits

Differential Revision: https://reviews.llvm.org/D46500

llvm-svn: 339172

1 files changed, 263 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.ll b/llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.ll
new file mode 100644
index 00000000000..45da0560646
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/cfg-stackify-eh.ll
@@ -0,0 +1,263 @@
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals -disable-block-placement -verify-machineinstrs -fast-isel=false -machine-sink-split-probability-threshold=0 -cgp-freq-ratio-to-skip-merge=1000 -exception-model=wasm -mattr=+exception-handling | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+@_ZTIi = external constant i8*
+@_ZTId = external constant i8*
+
+; Simple test case with two catch clauses
+
+; CHECK-LABEL: test0
+; CHECK:   call      foo@FUNCTION
+; CHECK: .LBB0_1:
+; CHECK:   i32.catch
+; CHECK:   i32.call  $drop=, _Unwind_CallPersonality@FUNCTION
+; CHECK:   i32.call  $drop=, __cxa_begin_catch@FUNCTION
+; CHECK:   call      bar@FUNCTION
+; CHECK:   call      __cxa_end_catch@FUNCTION
+; CHECK: .LBB0_3:
+; CHECK:   i32.call  $drop=, __cxa_begin_catch@FUNCTION
+; CHECK:   call      __cxa_end_catch@FUNCTION
+; CHECK: .LBB0_5:
+; CHECK:   call      __cxa_rethrow@FUNCTION
+; CHECK: .LBB0_6:
+; CHECK:   return
+define void @test0() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
+entry:
+  invoke void @foo()
+          to label %try.cont unwind label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %entry
+  %0 = catchswitch within none [label %catch.start] unwind to caller
+
+catch.start:                                      ; preds = %catch.dispatch
+  %1 = catchpad within %0 [i8* bitcast (i8** @_ZTIi to i8*), i8* bitcast (i8** @_ZTId to i8*)]
+  %2 = call i8* @llvm.wasm.get.exception(token %1)
+  %3 = call i32 @llvm.wasm.get.ehselector(token %1)
+  %4 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))
+  %matches = icmp eq i32 %3, %4
+  br i1 %matches, label %catch2, label %catch.fallthrough
+
+catch2:                                           ; preds = %catch.start
+  %5 = call i8* @__cxa_begin_catch(i8* %2) [ "funclet"(token %1) ]
+  %6 = bitcast i8* %5 to i32*
+  %7 = load i32, i32* %6, align 4
+  call void @bar() [ "funclet"(token %1) ]
+  call void @__cxa_end_catch() [ "funclet"(token %1) ]
+  catchret from %1 to label %try.cont
+
+catch.fallthrough:                                ; preds = %catch.start
+  %8 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTId to i8*))
+  %matches1 = icmp eq i32 %3, %8
+  br i1 %matches1, label %catch, label %rethrow
+
+catch:                                            ; preds = %catch.fallthrough
+  %9 = call i8* @__cxa_begin_catch(i8* %2) [ "funclet"(token %1) ]
+  %10 = bitcast i8* %9 to double*
+  %11 = load double, double* %10, align 8
+  call void @__cxa_end_catch() [ "funclet"(token %1) ]
+  catchret from %1 to label %try.cont
+
+rethrow:                                          ; preds = %catch.fallthrough
+  call void @__cxa_rethrow() [ "funclet"(token %1) ]
+  unreachable
+
+try.cont:                                         ; preds = %entry, %catch, %catch2
+  ret void
+}
+
+; Nested try-catches within a catch
+
+; CHECK-LABEL: test1
+; CHECK:   call      foo@FUNCTION
+; CHECK: .LBB1_1:
+; CHECK:   i32.catch     $0=, 0
+; CHECK:   i32.call  $drop=, _Unwind_CallPersonality@FUNCTION, $0
+; CHECK:   i32.call  $drop=, __cxa_begin_catch@FUNCTION, $0
+; CHECK:   call      foo@FUNCTION
+; CHECK: .LBB1_3:
+; CHECK:   i32.catch     $0=, 0
+; CHECK:   i32.call  $drop=, _Unwind_CallPersonality@FUNCTION, $0
+; CHECK:   i32.call  $drop=, __cxa_begin_catch@FUNCTION, $0
+; CHECK:   call      foo@FUNCTION
+; CHECK: .LBB1_5:
+; CHECK:   catch_all
+; CHECK:   call      __cxa_end_catch@FUNCTION
+; CHECK:   rethrow
+; CHECK: .LBB1_6:
+; CHECK:   call      __cxa_rethrow@FUNCTION
+; CHECK:   rethrow
+; CHECK: .LBB1_7:
+; CHECK:   call      __cxa_end_catch@FUNCTION
+; CHECK: .LBB1_8:
+; CHECK:   catch_all
+; CHECK:   call      __cxa_end_catch@FUNCTION
+; CHECK: .LBB1_9:
+; CHECK:   call      __cxa_rethrow@FUNCTION
+; CHECK:   rethrow
+; CHECK: .LBB1_10:
+; CHECK:   call      __cxa_end_catch@FUNCTION
+; CHECK: .LBB1_11:
+; CHECK:   return
+define hidden void @test1() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
+entry:
+  invoke void @foo()
+          to label %try.cont11 unwind label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %entry
+  %0 = catchswitch within none [label %catch.start] unwind to caller
+
+catch.start:                                      ; preds = %catch.dispatch
+  %1 = catchpad within %0 [i8* bitcast (i8** @_ZTIi to i8*)]
+  %2 = call i8* @llvm.wasm.get.exception(token %1)
+  %3 = call i32 @llvm.wasm.get.ehselector(token %1)
+  %4 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))
+  %matches = icmp eq i32 %3, %4
+  br i1 %matches, label %catch, label %rethrow
+
+catch:                                            ; preds = %catch.start
+  %5 = call i8* @__cxa_begin_catch(i8* %2) [ "funclet"(token %1) ]
+  %6 = bitcast i8* %5 to i32*
+  %7 = load i32, i32* %6, align 4
+  invoke void @foo() [ "funclet"(token %1) ]
+          to label %try.cont unwind label %catch.dispatch2
+
+catch.dispatch2:                                  ; preds = %catch
+  %8 = catchswitch within %1 [label %catch.start3] unwind label %ehcleanup9
+
+catch.start3:                                     ; preds = %catch.dispatch2
+  %9 = catchpad within %8 [i8* bitcast (i8** @_ZTIi to i8*)]
+  %10 = call i8* @llvm.wasm.get.exception(token %9)
+  %11 = call i32 @llvm.wasm.get.ehselector(token %9)
+  %12 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))
+  %matches4 = icmp eq i32 %11, %12
+  br i1 %matches4, label %catch6, label %rethrow5
+
+catch6:                                           ; preds = %catch.start3
+  %13 = call i8* @__cxa_begin_catch(i8* %10) [ "funclet"(token %9) ]
+  %14 = bitcast i8* %13 to i32*
+  %15 = load i32, i32* %14, align 4
+  invoke void @foo() [ "funclet"(token %9) ]
+          to label %invoke.cont8 unwind label %ehcleanup
+
+invoke.cont8:                                     ; preds = %catch6
+  call void @__cxa_end_catch() [ "funclet"(token %9) ]
+  catchret from %9 to label %try.cont
+
+rethrow5:                                         ; preds = %catch.start3
+  invoke void @__cxa_rethrow() [ "funclet"(token %9) ]
+          to label %unreachable unwind label %ehcleanup9
+
+try.cont:                                         ; preds = %catch, %invoke.cont8
+  call void @__cxa_end_catch() [ "funclet"(token %1) ]
+  catchret from %1 to label %try.cont11
+
+rethrow:                                          ; preds = %catch.start
+  call void @__cxa_rethrow() [ "funclet"(token %1) ]
+  unreachable
+
+try.cont11:                                       ; preds = %entry, %try.cont
+  ret void
+
+ehcleanup:                                        ; preds = %catch6
+  %16 = cleanuppad within %9 []
+  call void @__cxa_end_catch() [ "funclet"(token %16) ]
+  cleanupret from %16 unwind label %ehcleanup9
+
+ehcleanup9:                                       ; preds = %ehcleanup, %rethrow5, %catch.dispatch2
+  %17 = cleanuppad within %1 []
+  call void @__cxa_end_catch() [ "funclet"(token %17) ]
+  cleanupret from %17 unwind to caller
+
+unreachable:                                      ; preds = %rethrow5
+  unreachable
+}
+
+; Nested loop within a catch clause
+
+; CHECK-LABEL: test2
+; CHECK:   call      foo@FUNCTION
+; CHECK: .LBB2_1:
+; CHECK:   i32.catch
+; CHECK:   i32.call  $drop=, __cxa_begin_catch@FUNCTION
+; CHECK: .LBB2_2:
+; CHECK:   call      foo@FUNCTION
+; CHECK: .LBB2_4:
+; CHECK:   catch_all
+; CHECK:   call      __cxa_end_catch@FUNCTION
+; CHECK: .LBB2_5:
+; CHECK:   i32.catch
+; CHECK:   call      __clang_call_terminate@FUNCTION
+; CHECK:   unreachable
+; CHECK: .LBB2_6:
+; CHECK:   catch_all
+; CHECK:   call      _ZSt9terminatev@FUNCTION
+; CHECK:   unreachable
+; CHECK: .LBB2_7:
+; CHECK:   rethrow
+; CHECK: .LBB2_8:
+; CHECK:   call      __cxa_end_catch@FUNCTION
+; CHECK: .LBB2_10:
+; CHECK:   return
+define void @test2() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
+entry:
+  invoke void @foo()
+          to label %try.cont unwind label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %entry
+  %0 = catchswitch within none [label %catch.start] unwind to caller
+
+catch.start:                                      ; preds = %catch.dispatch
+  %1 = catchpad within %0 [i8* null]
+  %2 = call i8* @llvm.wasm.get.exception(token %1)
+  %3 = call i32 @llvm.wasm.get.ehselector(token %1)
+  %4 = call i8* @__cxa_begin_catch(i8* %2) [ "funclet"(token %1) ]
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc, %catch.start
+  %i.0 = phi i32 [ 0, %catch.start ], [ %inc, %for.inc ]
+  %cmp = icmp slt i32 %i.0, 50
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  invoke void @foo() [ "funclet"(token %1) ]
+          to label %for.inc unwind label %ehcleanup
+
+for.inc:                                          ; preds = %for.body
+  %inc = add nsw i32 %i.0, 1
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  call void @__cxa_end_catch() [ "funclet"(token %1) ]
+  catchret from %1 to label %try.cont
+
+try.cont:                                         ; preds = %for.end, %entry
+  ret void
+
+ehcleanup:                                        ; preds = %for.body
+  %5 = cleanuppad within %1 []
+  invoke void @__cxa_end_catch() [ "funclet"(token %5) ]
+          to label %invoke.cont2 unwind label %terminate
+
+invoke.cont2:                                     ; preds = %ehcleanup
+  cleanupret from %5 unwind to caller
+
+terminate:                                        ; preds = %ehcleanup
+  %6 = cleanuppad within %5 []
+  %7 = call i8* @llvm.wasm.get.exception(token %6)
+  call void @__clang_call_terminate(i8* %7) [ "funclet"(token %6) ]
+  unreachable
+}
+
+declare void @foo()
+declare void @bar()
+declare i32 @__gxx_wasm_personality_v0(...)
+declare i8* @llvm.wasm.get.exception(token)
+declare i32 @llvm.wasm.get.ehselector(token)
+declare i32 @llvm.eh.typeid.for(i8*)
+declare i8* @__cxa_begin_catch(i8*)
+declare void @__cxa_end_catch()
+declare void @__cxa_rethrow()
+declare void @__clang_call_terminate(i8*)
+declare void @_ZSt9terminatev()