d1fd72343c
The idea is that the CC1 default for ELF should set dso_local on default
visibility external linkage definitions in the default -mrelocation-model pic
mode (-fpic/-fPIC) to match COFF/Mach-O and make output IR similar.
The refactoring is made available by 2820a2ca3a.
Currently only x86 supports local aliases. We move the decision to the driver.
There are three CC1 states:
* -fsemantic-interposition: make some linkages interposable and make default visibility external linkage definitions dso_preemptable.
* (default): selected if the target supports .Lfoo$local: make default visibility external linkage definitions dso_local
* -fhalf-no-semantic-interposition: if neither option is set or the target does not support .Lfoo$local: like -fno-semantic-interposition but local aliases are not used. So references can be interposed if not optimized out.
Add -fhalf-no-semantic-interposition to a few tests using the half-based semantic interposition behavior.
20 lines
1.4 KiB
C++
20 lines
1.4 KiB
C++
// The VTable is not in a comdat but the inline methods are.
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// This doesn’t affect the vtable or the stubs we emit.
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// RUN: %clang_cc1 %s -triple=aarch64 -O1 -S -o - -emit-llvm -fexperimental-relative-c++-abi-vtables -fhalf-no-semantic-interposition | FileCheck %s
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// RUN: %clang_cc1 %s -triple=x86_64 -O1 -S -o - -emit-llvm -fexperimental-relative-c++-abi-vtables -fhalf-no-semantic-interposition | FileCheck %s
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// CHECK: $_ZTI1A.rtti_proxy = comdat any
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// The vtable has a key function (A::foo()) so it does not have a comdat
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// CHECK: @_ZTV1A.local = private unnamed_addr constant { [4 x i32] } { [4 x i32] [i32 0, i32 trunc (i64 sub (i64 ptrtoint ({ i8*, i8* }** @_ZTI1A.rtti_proxy to i64), i64 ptrtoint (i32* getelementptr inbounds ({ [4 x i32] }, { [4 x i32] }* @_ZTV1A.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (void (%class.A*)* dso_local_equivalent @_ZN1A3fooEv to i64), i64 ptrtoint (i32* getelementptr inbounds ({ [4 x i32] }, { [4 x i32] }* @_ZTV1A.local, i32 0, i32 0, i32 2) to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (void (%class.A*)* dso_local_equivalent @_ZN1A3barEv to i64), i64 ptrtoint (i32* getelementptr inbounds ({ [4 x i32] }, { [4 x i32] }* @_ZTV1A.local, i32 0, i32 0, i32 2) to i64)) to i32)] }, align 4
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// CHECK: @_ZTV1A ={{.*}} unnamed_addr alias { [4 x i32] }, { [4 x i32] }* @_ZTV1A.local
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class A {
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public:
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virtual void foo(); // Key func
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inline virtual void bar() {}
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};
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void A::foo() {}
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