a896f7f218
Previously, this pass would convert any read-only use of a runtime.stringToBytes call to use the original string buffer instead. This is incorrect: if there are any writes to the resulting buffer, none of the slice buffer pointers can be converted to use the original read-only string buffer. This commit fixes that bug and adds a test to prove the new (correct) behavior.
48 строки
1,7 КиБ
LLVM
48 строки
1,7 КиБ
LLVM
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64--linux"
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@str = constant [6 x i8] c"foobar"
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declare { ptr, i64, i64 } @runtime.stringToBytes(ptr, i64)
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declare void @printSlice(ptr nocapture readonly, i64, i64)
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declare void @writeToSlice(ptr nocapture, i64, i64)
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; Test that runtime.stringToBytes can be fully optimized away.
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define void @testReadOnly() {
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entry:
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%0 = call fastcc { ptr, i64, i64 } @runtime.stringToBytes(ptr @str, i64 6)
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%1 = extractvalue { ptr, i64, i64 } %0, 0
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%2 = extractvalue { ptr, i64, i64 } %0, 1
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%3 = extractvalue { ptr, i64, i64 } %0, 2
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call fastcc void @printSlice(ptr %1, i64 %2, i64 %3)
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ret void
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}
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; Test that even though the slice is written to, some values can be propagated.
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define void @testReadWrite() {
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entry:
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%0 = call fastcc { ptr, i64, i64 } @runtime.stringToBytes(ptr @str, i64 6)
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%1 = extractvalue { ptr, i64, i64 } %0, 0
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%2 = extractvalue { ptr, i64, i64 } %0, 1
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%3 = extractvalue { ptr, i64, i64 } %0, 2
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call fastcc void @writeToSlice(ptr %1, i64 %2, i64 %3)
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ret void
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}
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; Test that pointer values are never propagated if there is even a single write
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; to the pointer value (but len/cap values still can be).
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define void @testReadSome() {
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entry:
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%s = call fastcc { ptr, i64, i64 } @runtime.stringToBytes(ptr @str, i64 6)
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%s.ptr = extractvalue { ptr, i64, i64 } %s, 0
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%s.len = extractvalue { ptr, i64, i64 } %s, 1
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%s.cap = extractvalue { ptr, i64, i64 } %s, 2
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call fastcc void @writeToSlice(ptr %s.ptr, i64 %s.len, i64 %s.cap)
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%s.ptr2 = extractvalue { ptr, i64, i64 } %s, 0
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%s.len2 = extractvalue { ptr, i64, i64 } %s, 1
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%s.cap2 = extractvalue { ptr, i64, i64 } %s, 2
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call fastcc void @printSlice(ptr %s.ptr2, i64 %s.len2, i64 %s.cap2)
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ret void
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}
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