9890c760cf
Previously, the function value lowering pass had special cases for when there were 0 or 1 function implementations. However, the results of the pass were incorrect in both of these cases. This change removes the specializations and fixes the transformation. In the case that there was a single function implementation, the compiler emitted a select instruction to obtain the function pointer. This selected between null and the implementing function pointer. While this was technically correct, it failed to eliminate indirect function calls. This prevented discovery of these calls by the coroutine lowering pass, and caused async function calls to be passed through unlowered. As a result, the generated code had undefined behavior (usually resulting in a segfault). In the case of no function implementations, the lowering code was correct. However, the lowering code was not run. The discovery of function signatures was accomplished by scanning implementations, and when there were no implementations nothing was discovered or lowered. For maintainability reasons, I have removed both specializations rather than fixing them. This substantially simplifies the code, and reduces the amount of variation that we need to worry about for testing purposes. The IR now generated in the cases of 0 or 1 function implementations can be efficiently simplified by LLVM's optimization passes. Therefore, there should not be a substantial regression in terms of performance or machine code size.
72 строки
3,2 КиБ
LLVM
72 строки
3,2 КиБ
LLVM
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
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target triple = "wasm32-unknown-unknown-wasm"
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%runtime.typecodeID = type { %runtime.typecodeID*, i32 }
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%runtime.funcValueWithSignature = type { i32, %runtime.typecodeID* }
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@"reflect/types.type:func:{basic:uint8}{}" = external constant %runtime.typecodeID
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@"reflect/types.type:func:{basic:int}{}" = external constant %runtime.typecodeID
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@"reflect/types.type:func:{}{basic:uint32}" = external constant %runtime.typecodeID
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@"func1Uint8$withSignature" = constant %runtime.funcValueWithSignature { i32 ptrtoint (void (i8, i8*, i8*)* @func1Uint8 to i32), %runtime.typecodeID* @"reflect/types.type:func:{basic:uint8}{}" }
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@"func2Uint8$withSignature" = constant %runtime.funcValueWithSignature { i32 ptrtoint (void (i8, i8*, i8*)* @func2Uint8 to i32), %runtime.typecodeID* @"reflect/types.type:func:{basic:uint8}{}" }
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@"main$withSignature" = constant %runtime.funcValueWithSignature { i32 ptrtoint (void (i32, i8*, i8*)* @"main$1" to i32), %runtime.typecodeID* @"reflect/types.type:func:{basic:int}{}" }
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@"main$2$withSignature" = constant %runtime.funcValueWithSignature { i32 ptrtoint (void (i32, i8*, i8*)* @"main$2" to i32), %runtime.typecodeID* @"reflect/types.type:func:{basic:int}{}" }
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declare i32 @runtime.getFuncPtr(i8*, i32, %runtime.typecodeID*, i8*, i8*)
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declare void @"internal/task.start"(i32, i8*, i8*, i8*)
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declare void @runtime.nilPanic(i8*, i8*)
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declare void @"main$1"(i32, i8*, i8*)
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declare void @"main$2"(i32, i8*, i8*)
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declare void @func1Uint8(i8, i8*, i8*)
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declare void @func2Uint8(i8, i8*, i8*)
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; There are no functions with this signature used in a func value.
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; This means that this should unconditionally nil panic.
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define i32 @runFuncNone(i8*, i32, i8* %context, i8* %parentHandle) {
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entry:
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%2 = call i32 @runtime.getFuncPtr(i8* %0, i32 %1, %runtime.typecodeID* @"reflect/types.type:func:{}{basic:uint32}", i8* undef, i8* null)
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%3 = inttoptr i32 %2 to i32 (i8*, i8*)*
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%4 = icmp eq i32 (i8*, i8*)* %3, null
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br i1 %4, label %fpcall.nil, label %fpcall.next
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fpcall.nil:
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call void @runtime.nilPanic(i8* undef, i8* null)
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unreachable
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fpcall.next:
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%5 = call i32 %3(i8* %0, i8* undef)
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ret i32 %5
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}
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; There are two functions with this signature used in a func value. That means
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; that we'll have to check at runtime which of the two it is (or whether the
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; func value is nil). This call will thus be lowered to a switch statement.
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define void @runFunc2(i8*, i32, i8, i8* %context, i8* %parentHandle) {
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entry:
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%3 = call i32 @runtime.getFuncPtr(i8* %0, i32 %1, %runtime.typecodeID* @"reflect/types.type:func:{basic:uint8}{}", i8* undef, i8* null)
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%4 = inttoptr i32 %3 to void (i8, i8*, i8*)*
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%5 = icmp eq void (i8, i8*, i8*)* %4, null
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br i1 %5, label %fpcall.nil, label %fpcall.next
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fpcall.nil:
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call void @runtime.nilPanic(i8* undef, i8* null)
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unreachable
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fpcall.next:
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call void %4(i8 %2, i8* %0, i8* undef)
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ret void
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}
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; Special case for internal/task.start.
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define void @sleepFuncValue(i8*, i32, i8* nocapture readnone %context, i8* nocapture readnone %parentHandle) {
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entry:
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%2 = call i32 @runtime.getFuncPtr(i8* %0, i32 %1, %runtime.typecodeID* @"reflect/types.type:func:{basic:int}{}", i8* undef, i8* null)
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call void @"internal/task.start"(i32 %2, i8* null, i8* undef, i8* null)
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ret void
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}
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