83305faeb5
When doing LTO on multiple archives, the order with which bitcodes are linked to the LTO module is hard to control, given that processing undefined symbols can lead to parsing of an object file, which in turn lead to parsing of another object file before finishing parsing of the previous file. This can result in encountering a non-prevailing comdat first when linking, which can make the the symbol undefined, and the real definition is added later with an additional prefix to avoid duplication (e.g. `__cxx_global_var_init` and `__cxx_global_var_init.2`) So this one-line fix ensures we compile bitcodes in the order that we process comdats, so that when multiple archived bitcode files have the same variable with the same comdat, we make sure that the prevailing comdat will be linked first in the LTO. Fixes #62243.
40 lines
1.1 KiB
LLVM
40 lines
1.1 KiB
LLVM
target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128"
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target triple = "wasm32-unknown-unknown"
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; Generated from this C++ code and simplified manually:
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;
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; int foo();
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; inline int unused = foo();
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;
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; int foo() {
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; return 42;
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; }
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$unused = comdat any
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@unused = linkonce_odr global i32 0, comdat, align 4
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@_ZGV6unused = linkonce_odr global i32 0, comdat($unused), align 4
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@llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init, ptr @unused }]
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define internal void @__cxx_global_var_init() comdat($unused) {
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entry:
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%0 = load i8, ptr @_ZGV6unused, align 4
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%1 = and i8 %0, 1
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%guard.uninitialized = icmp eq i8 %1, 0
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br i1 %guard.uninitialized, label %init.check, label %init.end
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init.check: ; preds = %entry
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store i8 1, ptr @_ZGV6unused, align 4
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%call = call i32 @foo()
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store i32 %call, ptr @unused, align 4
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br label %init.end
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init.end: ; preds = %init.check, %entry
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ret void
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}
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define i32 @foo() {
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entry:
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ret i32 42
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}
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