tinygo/compiler/testdata/basic.ll
Ayke van Laethem c41a212712 wasm: avoid miscompile with ThinLTO
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).
2023-01-18 08:24:42 +01:00

219 строки
6,3 КиБ
LLVM

; ModuleID = 'basic.go'
source_filename = "basic.go"
target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20"
target triple = "wasm32-unknown-wasi"
%main.kv = type { float, i32, i32, i32 }
%main.kv.0 = type { i8, i32, i32, i32 }
@main.kvGlobal = hidden global %main.kv zeroinitializer, align 4
@main.a = hidden global { ptr, i32, i32 } zeroinitializer, align 4
@main.b = hidden global [2 x ptr] zeroinitializer, align 4
declare noalias nonnull ptr @runtime.alloc(i32, ptr, ptr) #0
declare void @runtime.trackPointer(ptr nocapture readonly, ptr, ptr) #0
; Function Attrs: nounwind
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 #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 #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 #1 {
entry:
%0 = icmp eq i32 %y, 0
br i1 %0, label %divbyzero.throw, label %divbyzero.next
divbyzero.next: ; preds = %entry
%1 = icmp eq i32 %y, -1
%2 = icmp eq i32 %x, -2147483648
%3 = and i1 %1, %2
%4 = select i1 %3, i32 1, i32 %y
%5 = sdiv i32 %x, %4
ret i32 %5
divbyzero.throw: ; preds = %entry
call void @runtime.divideByZeroPanic(ptr undef) #2
unreachable
}
declare void @runtime.divideByZeroPanic(ptr) #0
; Function Attrs: nounwind
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
divbyzero.next: ; preds = %entry
%1 = udiv i32 %x, %y
ret i32 %1
divbyzero.throw: ; preds = %entry
call void @runtime.divideByZeroPanic(ptr undef) #2
unreachable
}
; Function Attrs: nounwind
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
divbyzero.next: ; preds = %entry
%1 = icmp eq i32 %y, -1
%2 = icmp eq i32 %x, -2147483648
%3 = and i1 %1, %2
%4 = select i1 %3, i32 1, i32 %y
%5 = srem i32 %x, %4
ret i32 %5
divbyzero.throw: ; preds = %entry
call void @runtime.divideByZeroPanic(ptr undef) #2
unreachable
}
; Function Attrs: nounwind
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
divbyzero.next: ; preds = %entry
%1 = urem i32 %x, %y
ret i32 %1
divbyzero.throw: ; preds = %entry
call void @runtime.divideByZeroPanic(ptr undef) #2
unreachable
}
; Function Attrs: nounwind
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 #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 #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 #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 #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 #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 #1 {
entry:
ret float %x.r
}
; Function Attrs: nounwind
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 #1 {
entry:
%0 = fadd float %x.r, %y.r
%1 = fadd float %x.i, %y.i
%2 = insertvalue { float, float } undef, float %0, 0
%3 = insertvalue { float, float } %2, float %1, 1
ret { float, float } %3
}
; 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 #1 {
entry:
%0 = fsub float %x.r, %y.r
%1 = fsub float %x.i, %y.i
%2 = insertvalue { float, float } undef, float %0, 0
%3 = insertvalue { float, float } %2, float %1, 1
ret { float, float } %3
}
; 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 #1 {
entry:
%0 = fmul float %x.r, %y.r
%1 = fmul float %x.i, %y.i
%2 = fsub float %0, %1
%3 = fmul float %x.r, %y.i
%4 = fmul float %x.i, %y.r
%5 = fadd float %3, %4
%6 = insertvalue { float, float } undef, float %2, 0
%7 = insertvalue { float, float } %6, float %5, 1
ret { float, float } %7
}
; Function Attrs: nounwind
define hidden void @main.foo(ptr %context) unnamed_addr #1 {
entry:
%complit = alloca %main.kv.0, align 8
%stackalloc = alloca i8, align 1
store %main.kv.0 zeroinitializer, ptr %complit, align 8
call void @runtime.trackPointer(ptr nonnull %complit, ptr nonnull %stackalloc, ptr undef) #2
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 #1 {
entry:
%b1 = alloca %main.kv.0, align 8
%stackalloc = alloca i8, align 1
store %main.kv.0 zeroinitializer, ptr %b1, align 8
call void @runtime.trackPointer(ptr nonnull %b1, ptr nonnull %stackalloc, ptr undef) #2
store %main.kv.0 %b, ptr %b1, align 8
ret void
}
attributes #0 = { "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" }
attributes #1 = { nounwind "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" }
attributes #2 = { nounwind }