[llvm] 26d587c - [WebAssembly] Error out for setjmp within catch clause for Wasm SjLj

[Heejin Ahn via llvm-commits]

Author: Heejin Ahn
Date: 2022-01-27T21:05:43-08:00
New Revision: 26d587cf0f153724dd9b4307773caa2ffba08ef4

URL: https://github.com/llvm/llvm-project/commit/26d587cf0f153724dd9b4307773caa2ffba08ef4
DIFF: https://github.com/llvm/llvm-project/commit/26d587cf0f153724dd9b4307773caa2ffba08ef4.diff

LOG: [WebAssembly] Error out for setjmp within catch clause for Wasm SjLj

Wasm EH, used with either of Emscripten SjLj or Wasm SjLj, does not
allow `setjmp` calls to be placed within a `catch` clause, because we
don't support jumping into a `catch` block. Emscripten EH does not have
this restriction. But I think this restriction wouldn't prevent most of
use cases. This CL errors out with a clear messsage for this case.

Reviewed By: dschuff, kripken

Differential Revision: https://reviews.llvm.org/D118286

Added: 
    llvm/test/CodeGen/WebAssembly/wasm-eh-sjlj-setjmp-within-catch.ll

Modified: 
    llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
index dc52c69fb566..6751b11fb793 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
@@ -1322,6 +1322,9 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runSjLjOnFunction(Function &F) {
     BasicBlock *BB = CB->getParent();
     if (BB->getParent() != &F) // in other function
       continue;
+    if (CB->getOperandBundle(LLVMContext::OB_funclet))
+      report_fatal_error(
+          "setjmp within a catch clause is not supported in Wasm EH");
 
     CallInst *CI = nullptr;
     // setjmp cannot throw. So if it is an invoke, lower it to a call

diff  --git a/llvm/test/CodeGen/WebAssembly/wasm-eh-sjlj-setjmp-within-catch.ll b/llvm/test/CodeGen/WebAssembly/wasm-eh-sjlj-setjmp-within-catch.ll
new file mode 100644
index 000000000000..d08644f8529e
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/wasm-eh-sjlj-setjmp-within-catch.ll
@@ -0,0 +1,70 @@
+; RUN: not --crash opt < %s -wasm-lower-em-ehsjlj -wasm-enable-eh -wasm-enable-sjlj -S 2>&1 | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+%struct.__jmp_buf_tag = type { [6 x i32], i32, [32 x i32] }
+ at _ZTIi = external constant i8*
+
+define void @setjmp_within_catch() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
+entry:
+  %buf = alloca [1 x %struct.__jmp_buf_tag], align 16
+  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*)) #0
+  %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) #0 [ "funclet"(token %1) ]
+  %6 = bitcast i8* %5 to i32*
+  %7 = load i32, i32* %6, align 4
+  %arraydecay = getelementptr inbounds [1 x %struct.__jmp_buf_tag], [1 x %struct.__jmp_buf_tag]* %buf, i32 0, i32 0
+; CHECK: LLVM ERROR: setjmp within a catch clause is not supported in Wasm EH
+  %call = invoke i32 @setjmp(%struct.__jmp_buf_tag* noundef %arraydecay) #2 [ "funclet"(token %1) ]
+          to label %invoke.cont1 unwind label %ehcleanup
+
+invoke.cont1:                                     ; preds = %catch
+  call void @__cxa_end_catch() #0 [ "funclet"(token %1) ]
+  catchret from %1 to label %try.cont
+
+rethrow:                                          ; preds = %catch.start
+  call void @llvm.wasm.rethrow() #1 [ "funclet"(token %1) ]
+  unreachable
+
+try.cont:                                         ; preds = %entry, %invoke.cont1
+  ret void
+
+ehcleanup:                                        ; preds = %catch
+  %8 = cleanuppad within %1 []
+  call void @__cxa_end_catch() #0 [ "funclet"(token %8) ]
+  cleanupret from %8 unwind to caller
+}
+
+
+declare void @foo()
+declare i32 @__gxx_wasm_personality_v0(...)
+; Function Attrs: nounwind
+declare i8* @llvm.wasm.get.exception(token) #0
+; Function Attrs: nounwind
+declare i32 @llvm.wasm.get.ehselector(token) #0
+; Function Attrs: nounwind
+declare i32 @llvm.eh.typeid.for(i8*) #0
+; Function Attrs: noreturn
+declare void @llvm.wasm.rethrow() #1
+declare i8* @__cxa_begin_catch(i8*)
+; Function Attrs: returns_twice
+declare i32 @setjmp(%struct.__jmp_buf_tag* noundef) #2
+declare void @__cxa_end_catch()
+
+attributes #0 = { nounwind }
+attributes #1 = { noreturn }
+attributes #2 = { returns_twice }