wasm: add recover support

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.
This commit is contained in:
Ayke van Laethem
2024-08-03 09:56:19 +02:00
parent 2f7952ff29
commit 89ffb47a0c
28 changed files with 885 additions and 397 deletions
+25 -24
View File
@@ -13,30 +13,31 @@ target triple = "wasm32-unknown-wasi"
; Function Attrs: allockind("alloc,zeroed") allocsize(0)
declare noalias nonnull ptr @runtime.alloc(i32, ptr, ptr) #0
; Function Attrs: nounwind
declare void @runtime.trackPointer(ptr nocapture readonly, ptr, ptr) #1
; Function Attrs: nounwind
define hidden void @main.init(ptr %context) unnamed_addr #2 {
define hidden void @main.init(ptr %context) unnamed_addr #1 {
entry:
ret void
}
; Function Attrs: nounwind
define hidden i32 @main.addInt(i32 %x, i32 %y, ptr %context) unnamed_addr #2 {
define hidden i32 @main.addInt(i32 %x, i32 %y, ptr %context) unnamed_addr #1 {
entry:
%0 = add i32 %x, %y
ret i32 %0
}
; Function Attrs: nounwind
define hidden i1 @main.equalInt(i32 %x, i32 %y, ptr %context) unnamed_addr #2 {
define hidden i1 @main.equalInt(i32 %x, i32 %y, ptr %context) unnamed_addr #1 {
entry:
%0 = icmp eq i32 %x, %y
ret i1 %0
}
; Function Attrs: nounwind
define hidden i32 @main.divInt(i32 %x, i32 %y, ptr %context) unnamed_addr #2 {
define hidden i32 @main.divInt(i32 %x, i32 %y, ptr %context) unnamed_addr #1 {
entry:
%0 = icmp eq i32 %y, 0
br i1 %0, label %divbyzero.throw, label %divbyzero.next
@@ -54,10 +55,10 @@ divbyzero.throw: ; preds = %entry
unreachable
}
declare void @runtime.divideByZeroPanic(ptr) #1
declare void @runtime.divideByZeroPanic(ptr) #2
; Function Attrs: nounwind
define hidden i32 @main.divUint(i32 %x, i32 %y, ptr %context) unnamed_addr #2 {
define hidden i32 @main.divUint(i32 %x, i32 %y, ptr %context) unnamed_addr #1 {
entry:
%0 = icmp eq i32 %y, 0
br i1 %0, label %divbyzero.throw, label %divbyzero.next
@@ -72,7 +73,7 @@ divbyzero.throw: ; preds = %entry
}
; Function Attrs: nounwind
define hidden i32 @main.remInt(i32 %x, i32 %y, ptr %context) unnamed_addr #2 {
define hidden i32 @main.remInt(i32 %x, i32 %y, ptr %context) unnamed_addr #1 {
entry:
%0 = icmp eq i32 %y, 0
br i1 %0, label %divbyzero.throw, label %divbyzero.next
@@ -91,7 +92,7 @@ divbyzero.throw: ; preds = %entry
}
; Function Attrs: nounwind
define hidden i32 @main.remUint(i32 %x, i32 %y, ptr %context) unnamed_addr #2 {
define hidden i32 @main.remUint(i32 %x, i32 %y, ptr %context) unnamed_addr #1 {
entry:
%0 = icmp eq i32 %y, 0
br i1 %0, label %divbyzero.throw, label %divbyzero.next
@@ -106,61 +107,61 @@ divbyzero.throw: ; preds = %entry
}
; Function Attrs: nounwind
define hidden i1 @main.floatEQ(float %x, float %y, ptr %context) unnamed_addr #2 {
define hidden i1 @main.floatEQ(float %x, float %y, ptr %context) unnamed_addr #1 {
entry:
%0 = fcmp oeq float %x, %y
ret i1 %0
}
; Function Attrs: nounwind
define hidden i1 @main.floatNE(float %x, float %y, ptr %context) unnamed_addr #2 {
define hidden i1 @main.floatNE(float %x, float %y, ptr %context) unnamed_addr #1 {
entry:
%0 = fcmp une float %x, %y
ret i1 %0
}
; Function Attrs: nounwind
define hidden i1 @main.floatLower(float %x, float %y, ptr %context) unnamed_addr #2 {
define hidden i1 @main.floatLower(float %x, float %y, ptr %context) unnamed_addr #1 {
entry:
%0 = fcmp olt float %x, %y
ret i1 %0
}
; Function Attrs: nounwind
define hidden i1 @main.floatLowerEqual(float %x, float %y, ptr %context) unnamed_addr #2 {
define hidden i1 @main.floatLowerEqual(float %x, float %y, ptr %context) unnamed_addr #1 {
entry:
%0 = fcmp ole float %x, %y
ret i1 %0
}
; Function Attrs: nounwind
define hidden i1 @main.floatGreater(float %x, float %y, ptr %context) unnamed_addr #2 {
define hidden i1 @main.floatGreater(float %x, float %y, ptr %context) unnamed_addr #1 {
entry:
%0 = fcmp ogt float %x, %y
ret i1 %0
}
; Function Attrs: nounwind
define hidden i1 @main.floatGreaterEqual(float %x, float %y, ptr %context) unnamed_addr #2 {
define hidden i1 @main.floatGreaterEqual(float %x, float %y, ptr %context) unnamed_addr #1 {
entry:
%0 = fcmp oge float %x, %y
ret i1 %0
}
; Function Attrs: nounwind
define hidden float @main.complexReal(float %x.r, float %x.i, ptr %context) unnamed_addr #2 {
define hidden float @main.complexReal(float %x.r, float %x.i, ptr %context) unnamed_addr #1 {
entry:
ret float %x.r
}
; Function Attrs: nounwind
define hidden float @main.complexImag(float %x.r, float %x.i, ptr %context) unnamed_addr #2 {
define hidden float @main.complexImag(float %x.r, float %x.i, ptr %context) unnamed_addr #1 {
entry:
ret float %x.i
}
; Function Attrs: nounwind
define hidden { float, float } @main.complexAdd(float %x.r, float %x.i, float %y.r, float %y.i, ptr %context) unnamed_addr #2 {
define hidden { float, float } @main.complexAdd(float %x.r, float %x.i, float %y.r, float %y.i, ptr %context) unnamed_addr #1 {
entry:
%0 = fadd float %x.r, %y.r
%1 = fadd float %x.i, %y.i
@@ -170,7 +171,7 @@ entry:
}
; Function Attrs: nounwind
define hidden { float, float } @main.complexSub(float %x.r, float %x.i, float %y.r, float %y.i, ptr %context) unnamed_addr #2 {
define hidden { float, float } @main.complexSub(float %x.r, float %x.i, float %y.r, float %y.i, ptr %context) unnamed_addr #1 {
entry:
%0 = fsub float %x.r, %y.r
%1 = fsub float %x.i, %y.i
@@ -180,7 +181,7 @@ entry:
}
; Function Attrs: nounwind
define hidden { float, float } @main.complexMul(float %x.r, float %x.i, float %y.r, float %y.i, ptr %context) unnamed_addr #2 {
define hidden { float, float } @main.complexMul(float %x.r, float %x.i, float %y.r, float %y.i, ptr %context) unnamed_addr #1 {
entry:
%0 = fmul float %x.r, %y.r
%1 = fmul float %x.i, %y.i
@@ -194,19 +195,19 @@ entry:
}
; Function Attrs: nounwind
define hidden void @main.foo(ptr %context) unnamed_addr #2 {
define hidden void @main.foo(ptr %context) unnamed_addr #1 {
entry:
call void @"main.foo$1"(%main.kv.0 zeroinitializer, ptr undef)
ret void
}
; Function Attrs: nounwind
define internal void @"main.foo$1"(%main.kv.0 %b, ptr %context) unnamed_addr #2 {
define internal void @"main.foo$1"(%main.kv.0 %b, ptr %context) unnamed_addr #1 {
entry:
ret void
}
attributes #0 = { allockind("alloc,zeroed") allocsize(0) "alloc-family"="runtime.alloc" "target-features"="+bulk-memory,+mutable-globals,+nontrapping-fptoint,+sign-ext" }
attributes #1 = { "target-features"="+bulk-memory,+mutable-globals,+nontrapping-fptoint,+sign-ext" }
attributes #2 = { nounwind "target-features"="+bulk-memory,+mutable-globals,+nontrapping-fptoint,+sign-ext" }
attributes #0 = { allockind("alloc,zeroed") allocsize(0) "alloc-family"="runtime.alloc" "target-features"="+bulk-memory,+exception-handling,+mutable-globals,+nontrapping-fptoint,+sign-ext" }
attributes #1 = { nounwind "target-features"="+bulk-memory,+exception-handling,+mutable-globals,+nontrapping-fptoint,+sign-ext" }
attributes #2 = { "target-features"="+bulk-memory,+exception-handling,+mutable-globals,+nontrapping-fptoint,+sign-ext" }
attributes #3 = { nounwind }