mirror of
https://github.com/tinygo-org/tinygo.git
synced 2026-08-06 12:03:41 +00:00
Ayke van Laethem
89ffb47a0c
Add unwinding and recover support for wasm using WebAssembly exception
handling. This still has a few gotchas:
* Many WASI systems don't support exception handling yet.
For example, see:
https://github.com/bytecodealliance/wasmtime/issues/2049
* Asyncify doesn't support wasm exception handling:
https://github.com/WebAssembly/binaryen/issues/4470
This means it's not possible to use goroutines together with
panic/recover.
* The current way that exceptions are implemented pretend to be C++
exceptions, but work slightly differently. If C++ code is called
(for example through CGo) that raises an exception, that exception
will be eaten by TinyGo and not be propagated. This is fixable, it
just hasn't been implemented (because we don't actually support C++
right now).
I hope that these issues will be resolved over time. At least for now,
people who need `recover()` have a way to use it.
274 lines
12 KiB
LLVM
274 lines
12 KiB
LLVM
; ModuleID = 'defer.go'
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source_filename = "defer.go"
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target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20"
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target triple = "wasm32-unknown-wasi"
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%runtime.deferFrameWasmEH = type { ptr, i1, %runtime._interface }
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%runtime._interface = type { ptr, ptr }
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%runtime._defer = type { i32, ptr }
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; Function Attrs: allockind("alloc,zeroed") allocsize(0)
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declare noalias nonnull ptr @runtime.alloc(i32, ptr, ptr) #0
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; Function Attrs: nounwind
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declare void @runtime.trackPointer(ptr nocapture readonly, ptr, ptr) #1
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define hidden void @main.init(ptr %context) unnamed_addr #2 {
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entry:
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ret void
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}
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declare void @main.external(ptr) #2
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define hidden void @main.deferSimple(ptr %context) unnamed_addr #2 personality ptr @__gxx_wasm_personality_v0 {
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entry:
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%defer.alloca = alloca { i32, ptr }, align 8
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%deferPtr = alloca ptr, align 4
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store ptr null, ptr %deferPtr, align 4
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%deferframe.buf = alloca %runtime.deferFrameWasmEH, align 8
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call void @runtime.setupDeferFrameWasmEH(ptr nonnull %deferframe.buf, ptr undef)
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%stackalloc = alloca i8, align 1
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call void @runtime.trackPointer(ptr nonnull %defer.alloca, ptr nonnull %stackalloc, ptr undef)
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store i32 0, ptr %defer.alloca, align 4
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%defer.alloca.repack13 = getelementptr inbounds { i32, ptr }, ptr %defer.alloca, i32 0, i32 1
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store ptr null, ptr %defer.alloca.repack13, align 4
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store ptr %defer.alloca, ptr %deferPtr, align 4
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invoke void @main.external(ptr undef)
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to label %invoke.cont unwind label %catch.dispatch
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invoke.cont: ; preds = %entry
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br label %rundefers.block
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rundefers.after: ; preds = %rundefers.end
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call void @runtime.destroyDeferFrameWasmEH(ptr nonnull %deferframe.buf, ptr undef)
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ret void
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rundefers.block: ; preds = %invoke.cont
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br label %rundefers.loophead
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rundefers.loophead: ; preds = %rundefers.catch.start, %rundefers.callback0, %rundefers.block
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%0 = load ptr, ptr %deferPtr, align 4
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%stackIsNil = icmp eq ptr %0, null
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br i1 %stackIsNil, label %rundefers.end, label %rundefers.loop
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rundefers.loop: ; preds = %rundefers.loophead
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%stack.next.gep = getelementptr inbounds %runtime._defer, ptr %0, i32 0, i32 1
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%stack.next = load ptr, ptr %stack.next.gep, align 4
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store ptr %stack.next, ptr %deferPtr, align 4
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%callback = load i32, ptr %0, align 4
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switch i32 %callback, label %rundefers.default [
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i32 0, label %rundefers.callback0
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]
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rundefers.callback0: ; preds = %rundefers.loop
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invoke void @"main.deferSimple$1"(ptr undef)
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to label %rundefers.loophead unwind label %rundefers.catch.dispatch
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rundefers.default: ; preds = %rundefers.loop
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unreachable
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rundefers.catch.dispatch: ; preds = %rundefers.callback0
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%1 = catchswitch within none [label %rundefers.catch.start] unwind to caller
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rundefers.catch.start: ; preds = %rundefers.catch.dispatch
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%2 = catchpad within %1 [ptr null]
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catchret from %2 to label %rundefers.loophead
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rundefers.end: ; preds = %rundefers.loophead
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br label %rundefers.after
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recover: ; preds = %rundefers.end1
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call void @runtime.destroyDeferFrameWasmEH(ptr nonnull %deferframe.buf, ptr undef)
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ret void
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catch.dispatch: ; preds = %entry
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%3 = catchswitch within none [label %catch.start] unwind to caller
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catch.start: ; preds = %catch.dispatch
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%4 = catchpad within %3 [ptr null]
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catchret from %4 to label %rundefers
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rundefers: ; preds = %catch.start
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br label %rundefers.loophead4
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rundefers.loophead4: ; preds = %rundefers.catch.start6, %rundefers.callback012, %rundefers
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%5 = load ptr, ptr %deferPtr, align 4
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%stackIsNil7 = icmp eq ptr %5, null
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br i1 %stackIsNil7, label %rundefers.end1, label %rundefers.loop3
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rundefers.loop3: ; preds = %rundefers.loophead4
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%stack.next.gep8 = getelementptr inbounds %runtime._defer, ptr %5, i32 0, i32 1
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%stack.next9 = load ptr, ptr %stack.next.gep8, align 4
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store ptr %stack.next9, ptr %deferPtr, align 4
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%callback11 = load i32, ptr %5, align 4
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switch i32 %callback11, label %rundefers.default2 [
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i32 0, label %rundefers.callback012
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]
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rundefers.callback012: ; preds = %rundefers.loop3
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invoke void @"main.deferSimple$1"(ptr undef)
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to label %rundefers.loophead4 unwind label %rundefers.catch.dispatch5
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rundefers.default2: ; preds = %rundefers.loop3
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unreachable
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rundefers.catch.dispatch5: ; preds = %rundefers.callback012
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%6 = catchswitch within none [label %rundefers.catch.start6] unwind to caller
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rundefers.catch.start6: ; preds = %rundefers.catch.dispatch5
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%7 = catchpad within %6 [ptr null]
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catchret from %7 to label %rundefers.loophead4
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rundefers.end1: ; preds = %rundefers.loophead4
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br label %recover
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}
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declare i32 @__gxx_wasm_personality_v0(...)
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declare void @runtime.setupDeferFrameWasmEH(ptr dereferenceable_or_null(16), ptr) #2
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declare void @runtime.destroyDeferFrameWasmEH(ptr dereferenceable_or_null(16), ptr) #2
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define internal void @"main.deferSimple$1"(ptr %context) unnamed_addr #2 {
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entry:
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call void @runtime.printint32(i32 3, ptr undef)
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ret void
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}
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declare void @runtime.printint32(i32, ptr) #2
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define hidden void @main.deferMultiple(ptr %context) unnamed_addr #2 personality ptr @__gxx_wasm_personality_v0 {
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entry:
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%defer.alloca2 = alloca { i32, ptr }, align 8
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%defer.alloca = alloca { i32, ptr }, align 8
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%deferPtr = alloca ptr, align 4
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store ptr null, ptr %deferPtr, align 4
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%deferframe.buf = alloca %runtime.deferFrameWasmEH, align 8
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call void @runtime.setupDeferFrameWasmEH(ptr nonnull %deferframe.buf, ptr undef)
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%stackalloc = alloca i8, align 1
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call void @runtime.trackPointer(ptr nonnull %defer.alloca, ptr nonnull %stackalloc, ptr undef)
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store i32 0, ptr %defer.alloca, align 4
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%defer.alloca.repack16 = getelementptr inbounds { i32, ptr }, ptr %defer.alloca, i32 0, i32 1
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store ptr null, ptr %defer.alloca.repack16, align 4
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store ptr %defer.alloca, ptr %deferPtr, align 4
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call void @runtime.trackPointer(ptr nonnull %defer.alloca2, ptr nonnull %stackalloc, ptr undef)
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store i32 1, ptr %defer.alloca2, align 4
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%defer.alloca2.repack17 = getelementptr inbounds { i32, ptr }, ptr %defer.alloca2, i32 0, i32 1
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store ptr %defer.alloca, ptr %defer.alloca2.repack17, align 4
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store ptr %defer.alloca2, ptr %deferPtr, align 4
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invoke void @main.external(ptr undef)
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to label %invoke.cont unwind label %catch.dispatch
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invoke.cont: ; preds = %entry
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br label %rundefers.block
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rundefers.after: ; preds = %rundefers.end
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call void @runtime.destroyDeferFrameWasmEH(ptr nonnull %deferframe.buf, ptr undef)
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ret void
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rundefers.block: ; preds = %invoke.cont
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br label %rundefers.loophead
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rundefers.loophead: ; preds = %rundefers.catch.start, %rundefers.callback1, %rundefers.callback0, %rundefers.block
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%0 = load ptr, ptr %deferPtr, align 4
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%stackIsNil = icmp eq ptr %0, null
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br i1 %stackIsNil, label %rundefers.end, label %rundefers.loop
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rundefers.loop: ; preds = %rundefers.loophead
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%stack.next.gep = getelementptr inbounds %runtime._defer, ptr %0, i32 0, i32 1
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%stack.next = load ptr, ptr %stack.next.gep, align 4
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store ptr %stack.next, ptr %deferPtr, align 4
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%callback = load i32, ptr %0, align 4
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switch i32 %callback, label %rundefers.default [
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i32 0, label %rundefers.callback0
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i32 1, label %rundefers.callback1
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]
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rundefers.callback0: ; preds = %rundefers.loop
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invoke void @"main.deferMultiple$1"(ptr undef)
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to label %rundefers.loophead unwind label %rundefers.catch.dispatch
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rundefers.callback1: ; preds = %rundefers.loop
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invoke void @"main.deferMultiple$2"(ptr undef)
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to label %rundefers.loophead unwind label %rundefers.catch.dispatch
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rundefers.default: ; preds = %rundefers.loop
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unreachable
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rundefers.catch.dispatch: ; preds = %rundefers.callback1, %rundefers.callback0
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%1 = catchswitch within none [label %rundefers.catch.start] unwind to caller
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rundefers.catch.start: ; preds = %rundefers.catch.dispatch
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%2 = catchpad within %1 [ptr null]
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catchret from %2 to label %rundefers.loophead
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rundefers.end: ; preds = %rundefers.loophead
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br label %rundefers.after
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recover: ; preds = %rundefers.end3
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call void @runtime.destroyDeferFrameWasmEH(ptr nonnull %deferframe.buf, ptr undef)
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ret void
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catch.dispatch: ; preds = %entry
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%3 = catchswitch within none [label %catch.start] unwind to caller
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catch.start: ; preds = %catch.dispatch
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%4 = catchpad within %3 [ptr null]
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catchret from %4 to label %rundefers
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rundefers: ; preds = %catch.start
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br label %rundefers.loophead6
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rundefers.loophead6: ; preds = %rundefers.catch.start8, %rundefers.callback115, %rundefers.callback014, %rundefers
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%5 = load ptr, ptr %deferPtr, align 4
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%stackIsNil9 = icmp eq ptr %5, null
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br i1 %stackIsNil9, label %rundefers.end3, label %rundefers.loop5
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rundefers.loop5: ; preds = %rundefers.loophead6
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%stack.next.gep10 = getelementptr inbounds %runtime._defer, ptr %5, i32 0, i32 1
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%stack.next11 = load ptr, ptr %stack.next.gep10, align 4
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store ptr %stack.next11, ptr %deferPtr, align 4
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%callback13 = load i32, ptr %5, align 4
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switch i32 %callback13, label %rundefers.default4 [
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i32 0, label %rundefers.callback014
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i32 1, label %rundefers.callback115
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]
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rundefers.callback014: ; preds = %rundefers.loop5
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invoke void @"main.deferMultiple$1"(ptr undef)
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to label %rundefers.loophead6 unwind label %rundefers.catch.dispatch7
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rundefers.callback115: ; preds = %rundefers.loop5
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invoke void @"main.deferMultiple$2"(ptr undef)
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to label %rundefers.loophead6 unwind label %rundefers.catch.dispatch7
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rundefers.default4: ; preds = %rundefers.loop5
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unreachable
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rundefers.catch.dispatch7: ; preds = %rundefers.callback115, %rundefers.callback014
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%6 = catchswitch within none [label %rundefers.catch.start8] unwind to caller
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rundefers.catch.start8: ; preds = %rundefers.catch.dispatch7
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%7 = catchpad within %6 [ptr null]
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catchret from %7 to label %rundefers.loophead6
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rundefers.end3: ; preds = %rundefers.loophead6
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br label %recover
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}
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define internal void @"main.deferMultiple$1"(ptr %context) unnamed_addr #2 {
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entry:
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call void @runtime.printint32(i32 3, ptr undef)
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ret void
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}
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define internal void @"main.deferMultiple$2"(ptr %context) unnamed_addr #2 {
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entry:
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call void @runtime.printint32(i32 5, ptr undef)
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ret void
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}
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attributes #0 = { allockind("alloc,zeroed") allocsize(0) "alloc-family"="runtime.alloc" "target-features"="+bulk-memory,+exception-handling,+mutable-globals,+nontrapping-fptoint,+sign-ext" }
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attributes #1 = { nounwind "target-features"="+bulk-memory,+exception-handling,+mutable-globals,+nontrapping-fptoint,+sign-ext" }
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attributes #2 = { "target-features"="+bulk-memory,+exception-handling,+mutable-globals,+nontrapping-fptoint,+sign-ext" }
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