bc48b3f8b8
When generating C++ vtables, Clang declares virtual functions as `void(void)` when their signature is not known (e.g.parameter types are forward-declared). As WASM type checks imports, this would conflict with the real definition during linking. Commit 59f959ff introduced a workaround for this by deferring signature assignment until a definition or direct call is seen. When performing LTO, LLD first scans the bitcode files and creates `DefinedFunction` symbol table entries for their contents. After LTO codegen, they are replaced with `UndefinedFunction`s (so that the definitions will be pulled in from the native LTO-d files when they are added). At this point, if a function is only referenced in bitcode, its signature remains `nullptr`. From here, it should have behaved like in the non-LTO case: the first direct call sets the signature. However, as the `isCalledDirectly` flag was set to true, the missing signature was filled in by the type of the first reference to the function, which could be a `void(void)` vtable entry, which would then conflict with the real definition. This commit sets `isCalledDirectly` to false so that the signature will only be populated when a direct call is found. See godotengine/godot#104497 and emscripten-core/emscripten#10831
46 lines
1.3 KiB
LLVM
46 lines
1.3 KiB
LLVM
; RUN: rm -rf %t && split-file %s %t && cd %t
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; RUN: opt -thinlto-bc a.ll -o a.o
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; RUN: opt -thinlto-bc b.ll -o b.o
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; RUN: llvm-ar rcs b.a b.o
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; RUN: opt -thinlto-bc c.ll -o c.o
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;; Taking the address of the incorrectly declared @foo should not generate a warning.
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; RUN: wasm-ld --fatal-warnings --no-entry --export-all a.o b.a -o a.out \
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; RUN: | FileCheck %s --implicit-check-not 'warning' --allow-empty
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;; But we should still warn if we call the function with the wrong signature.
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; RUN: not wasm-ld --fatal-warnings --no-entry --export-all a.o b.a c.o -o b.out 2>&1 \
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; RUN: | FileCheck %s --check-prefix=INVALID
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; INVALID: error: function signature mismatch: foo
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; INVALID: >>> defined as () -> void
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; INVALID: >>> defined as () -> i32
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;--- a.ll
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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-unknown"
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@ptr = constant ptr @foo
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declare void @foo()
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;--- b.ll
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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-unknown"
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define i32 @foo() noinline {
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entry:
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ret i32 42
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}
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;--- c.ll
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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-unknown"
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declare void @foo()
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define void @invalid() {
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entry:
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call void @foo()
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ret void
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}
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