c41a212712
I found that when I enable ThinLTO, a miscompilation triggers that had
been hidden all the time previously. The bug appears to happen as
follows:
1. TinyGo generates a function with a runtime.trackPointer call, but
without an alloca (or the alloca gets optimized away).
2. LLVM sees that no alloca needs to be kept alive across the
runtime.trackPointer call, and therefore it adds the 'tail' flag.
One of the effects of this flag is that it makes it undefined
behavior to keep allocas alive across the call (which is still safe
at that point).
3. The GC lowering pass adds a stack slot alloca and converts
runtime.trackPointer calls into alloca stores.
The last step triggers the bug: the compiler inserts an alloca where
there was none before but that's not valid as long as the 'tail' flag is
present.
This patch fixes the bug in a somewhat dirty way, by always creating a
dummy alloca so that LLVM won't do the optimization in step 2 (and
possibly other optimizations that rely on there being no alloca
instruction).
138 строки
7,8 КиБ
LLVM
138 строки
7,8 КиБ
LLVM
; ModuleID = 'interface.go'
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source_filename = "interface.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.typecodeID = type { ptr, i32, ptr, ptr, i32 }
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%runtime._interface = type { i32, ptr }
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%runtime._string = type { ptr, i32 }
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@"reflect/types.type:basic:int" = linkonce_odr constant %runtime.typecodeID { ptr null, i32 0, ptr null, ptr @"reflect/types.type:pointer:basic:int", i32 0 }
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@"reflect/types.type:pointer:basic:int" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.type:basic:int", i32 0, ptr null, ptr null, i32 0 }
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@"reflect/types.type:pointer:named:error" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.type:named:error", i32 0, ptr null, ptr null, i32 0 }
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@"reflect/types.type:named:error" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.type:interface:{Error:func:{}{basic:string}}", i32 0, ptr null, ptr @"reflect/types.type:pointer:named:error", i32 ptrtoint (ptr @"interface:{Error:func:{}{basic:string}}.$typeassert" to i32) }
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@"reflect/types.type:interface:{Error:func:{}{basic:string}}" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.interface:interface{Error() string}$interface", i32 0, ptr null, ptr @"reflect/types.type:pointer:interface:{Error:func:{}{basic:string}}", i32 ptrtoint (ptr @"interface:{Error:func:{}{basic:string}}.$typeassert" to i32) }
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@"reflect/methods.Error() string" = linkonce_odr constant i8 0, align 1
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@"reflect/types.interface:interface{Error() string}$interface" = linkonce_odr constant [1 x ptr] [ptr @"reflect/methods.Error() string"]
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@"reflect/types.type:pointer:interface:{Error:func:{}{basic:string}}" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.type:interface:{Error:func:{}{basic:string}}", i32 0, ptr null, ptr null, i32 0 }
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@"reflect/types.type:pointer:interface:{String:func:{}{basic:string}}" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.type:interface:{String:func:{}{basic:string}}", i32 0, ptr null, ptr null, i32 0 }
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@"reflect/types.type:interface:{String:func:{}{basic:string}}" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.interface:interface{String() string}$interface", i32 0, ptr null, ptr @"reflect/types.type:pointer:interface:{String:func:{}{basic:string}}", i32 ptrtoint (ptr @"interface:{String:func:{}{basic:string}}.$typeassert" to i32) }
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@"reflect/methods.String() string" = linkonce_odr constant i8 0, align 1
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@"reflect/types.interface:interface{String() string}$interface" = linkonce_odr constant [1 x ptr] [ptr @"reflect/methods.String() string"]
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@"reflect/types.typeid:basic:int" = external constant i8
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declare noalias nonnull ptr @runtime.alloc(i32, ptr, ptr) #0
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declare void @runtime.trackPointer(ptr nocapture readonly, ptr, ptr) #0
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; Function Attrs: nounwind
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define hidden void @main.init(ptr %context) unnamed_addr #1 {
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entry:
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ret void
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}
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; Function Attrs: nounwind
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define hidden %runtime._interface @main.simpleType(ptr %context) unnamed_addr #1 {
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entry:
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%stackalloc = alloca i8, align 1
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call void @runtime.trackPointer(ptr null, ptr nonnull %stackalloc, ptr undef) #6
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ret %runtime._interface { i32 ptrtoint (ptr @"reflect/types.type:basic:int" to i32), ptr null }
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}
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; Function Attrs: nounwind
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define hidden %runtime._interface @main.pointerType(ptr %context) unnamed_addr #1 {
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entry:
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%stackalloc = alloca i8, align 1
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call void @runtime.trackPointer(ptr null, ptr nonnull %stackalloc, ptr undef) #6
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ret %runtime._interface { i32 ptrtoint (ptr @"reflect/types.type:pointer:basic:int" to i32), ptr null }
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}
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; Function Attrs: nounwind
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define hidden %runtime._interface @main.interfaceType(ptr %context) unnamed_addr #1 {
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entry:
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%stackalloc = alloca i8, align 1
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call void @runtime.trackPointer(ptr null, ptr nonnull %stackalloc, ptr undef) #6
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ret %runtime._interface { i32 ptrtoint (ptr @"reflect/types.type:pointer:named:error" to i32), ptr null }
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}
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declare i1 @"interface:{Error:func:{}{basic:string}}.$typeassert"(i32) #2
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; Function Attrs: nounwind
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define hidden %runtime._interface @main.anonymousInterfaceType(ptr %context) unnamed_addr #1 {
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entry:
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%stackalloc = alloca i8, align 1
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call void @runtime.trackPointer(ptr null, ptr nonnull %stackalloc, ptr undef) #6
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ret %runtime._interface { i32 ptrtoint (ptr @"reflect/types.type:pointer:interface:{String:func:{}{basic:string}}" to i32), ptr null }
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}
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declare i1 @"interface:{String:func:{}{basic:string}}.$typeassert"(i32) #3
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; Function Attrs: nounwind
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define hidden i1 @main.isInt(i32 %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
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entry:
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%typecode = call i1 @runtime.typeAssert(i32 %itf.typecode, ptr nonnull @"reflect/types.typeid:basic:int", ptr undef) #6
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br i1 %typecode, label %typeassert.ok, label %typeassert.next
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typeassert.next: ; preds = %typeassert.ok, %entry
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ret i1 %typecode
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typeassert.ok: ; preds = %entry
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br label %typeassert.next
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}
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declare i1 @runtime.typeAssert(i32, ptr dereferenceable_or_null(1), ptr) #0
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; Function Attrs: nounwind
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define hidden i1 @main.isError(i32 %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
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entry:
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%0 = call i1 @"interface:{Error:func:{}{basic:string}}.$typeassert"(i32 %itf.typecode) #6
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br i1 %0, label %typeassert.ok, label %typeassert.next
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typeassert.next: ; preds = %typeassert.ok, %entry
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ret i1 %0
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typeassert.ok: ; preds = %entry
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br label %typeassert.next
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}
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; Function Attrs: nounwind
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define hidden i1 @main.isStringer(i32 %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
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entry:
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%0 = call i1 @"interface:{String:func:{}{basic:string}}.$typeassert"(i32 %itf.typecode) #6
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br i1 %0, label %typeassert.ok, label %typeassert.next
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typeassert.next: ; preds = %typeassert.ok, %entry
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ret i1 %0
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typeassert.ok: ; preds = %entry
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br label %typeassert.next
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}
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; Function Attrs: nounwind
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define hidden i8 @main.callFooMethod(i32 %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
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entry:
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%0 = call i8 @"interface:{String:func:{}{basic:string},main.foo:func:{basic:int}{basic:uint8}}.foo$invoke"(ptr %itf.value, i32 3, i32 %itf.typecode, ptr undef) #6
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ret i8 %0
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}
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declare i8 @"interface:{String:func:{}{basic:string},main.foo:func:{basic:int}{basic:uint8}}.foo$invoke"(ptr, i32, i32, ptr) #4
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; Function Attrs: nounwind
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define hidden %runtime._string @main.callErrorMethod(i32 %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
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entry:
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%stackalloc = alloca i8, align 1
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%0 = call %runtime._string @"interface:{Error:func:{}{basic:string}}.Error$invoke"(ptr %itf.value, i32 %itf.typecode, ptr undef) #6
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%1 = extractvalue %runtime._string %0, 0
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call void @runtime.trackPointer(ptr %1, ptr nonnull %stackalloc, ptr undef) #6
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ret %runtime._string %0
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}
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declare %runtime._string @"interface:{Error:func:{}{basic:string}}.Error$invoke"(ptr, i32, ptr) #5
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attributes #0 = { "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" }
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attributes #1 = { nounwind "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" }
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attributes #2 = { "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" "tinygo-methods"="reflect/methods.Error() string" }
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attributes #3 = { "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" "tinygo-methods"="reflect/methods.String() string" }
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attributes #4 = { "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" "tinygo-invoke"="main.$methods.foo(int) uint8" "tinygo-methods"="reflect/methods.String() string; main.$methods.foo(int) uint8" }
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attributes #5 = { "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" "tinygo-invoke"="reflect/methods.Error() string" "tinygo-methods"="reflect/methods.Error() string" }
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attributes #6 = { nounwind }
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