[WebAssembly] Add isEHScopeReturn instruction property
Summary:
So far, `isReturn` property is used to mean both a return instruction
from a functon and the end of an EH scope, a scope that starts with a EH
scope entry BB and ends with a catchret or a cleanupret instruction.
Because WinEH uses funclets, all EH-scope-ending instructions are also
real return instruction from a function. But for wasm, they only serve
as the end marker of an EH scope but not a return instruction that
exits a function. This mismatch caused incorrect prolog and epilog
generation in wasm EH scopes. This patch fixes this.
This patch is in the same vein with rL333045, which splits
`MachineBasicBlock::isEHFuncletEntry` into `isEHFuncletEntry` and
`isEHScopeEntry`.
Reviewers: dschuff
Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D50653
llvm-svn: 340325
diff --git a/llvm/test/CodeGen/WebAssembly/exception.ll b/llvm/test/CodeGen/WebAssembly/exception.ll
index 114311c..c2ad8d7 100644
--- a/llvm/test/CodeGen/WebAssembly/exception.ll
+++ b/llvm/test/CodeGen/WebAssembly/exception.ll
@@ -150,7 +150,71 @@
unreachable
}
+; Tests prologues and epilogues are not generated within EH scopes.
+; They should not be treated as funclets; BBs starting with a catch instruction
+; should not have a prologue, and BBs ending with a catchret/cleanupret should
+; not have an epilogue. This is separate from __stack_pointer restoring
+; instructions after a catch instruction.
+
+; CHECK-LABEL: test_no_prolog_epilog_in_ehpad
+; CHECK: try
+; CHECK: call foo@FUNCTION
+; CHECK: i32.catch
+; CHECK-NOT: get_global $push{{.+}}=, __stack_pointer@GLOBAL
+; CHECK: try
+; CHECK: call foo@FUNCTION
+; CHECK: catch_all
+; TODO This should be removed too in a later patch
+; CHECK-NO T: get_global $push{{.+}}=, __stack_pointer@GLOBAL
+; CHECK: call __cxa_end_catch@FUNCTION
+; CHECK-NOT: set_global __stack_pointer@GLOBAL, $pop{{.+}}
+; CHECK: end_try
+; CHECK-NOT: set_global __stack_pointer@GLOBAL, $pop{{.+}}
+; CHECK: end_try
+define void @test_no_prolog_epilog_in_ehpad() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
+entry:
+ %stack_var = alloca i32, align 4
+ call void @bar(i32* %stack_var)
+ 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*)]
+ %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 float*
+ %7 = load float, float* %6, align 4
+ invoke void @foo() [ "funclet"(token %1) ]
+ to label %invoke.cont1 unwind label %ehcleanup
+
+invoke.cont1: ; preds = %catch
+ call void @__cxa_end_catch() [ "funclet"(token %1) ]
+ catchret from %1 to label %try.cont
+
+rethrow: ; preds = %catch.start
+ call void @__cxa_rethrow() [ "funclet"(token %1) ]
+ unreachable
+
+try.cont: ; preds = %entry, %invoke.cont1
+ ret void
+
+ehcleanup: ; preds = %catch
+ %8 = cleanuppad within %1 []
+ call void @__cxa_end_catch() [ "funclet"(token %8) ]
+ cleanupret from %8 unwind to caller
+}
+
declare void @foo()
+declare void @bar(i32*)
declare i32 @__gxx_wasm_personality_v0(...)
declare i8* @llvm.wasm.get.exception(token)
declare i32 @llvm.wasm.get.ehselector(token)