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 2820a2ca3a0e69c3f301845420e0067ffff2251b. 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.
39 lines
1.6 KiB
C
39 lines
1.6 KiB
C
/// -fno-semantic-interposition is the default and local aliases (via dso_local) are allowed.
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// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -mrelocation-model pic -pic-level 1 %s -o - | FileCheck %s --check-prefixes=CHECK,NOMETADATA
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/// -fsemantic-interposition sets a module metadata.
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// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -mrelocation-model pic -pic-level 1 -fsemantic-interposition %s -o - | FileCheck %s --check-prefixes=PREEMPT,METADATA
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/// Traditional half-baked behavior: interprocedural optimizations are allowed
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/// but local aliases are not used.
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// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -mrelocation-model pic -pic-level 1 -fhalf-no-semantic-interposition %s -o - | FileCheck %s --check-prefixes=PREEMPT,NOMETADATA
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// CHECK: @var = dso_local global i32 0, align 4
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// CHECK: @ext_var = external global i32, align 4
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// CHECK: @ifunc = ifunc i32 (), bitcast (i8* ()* @ifunc_resolver to i32 ()*)
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// CHECK: define dso_local i32 @func()
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// CHECK: declare i32 @ext()
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// PREEMPT: @var = global i32 0, align 4
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// PREEMPT: @ext_var = external global i32, align 4
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// PREEMPT: @ifunc = ifunc i32 (), bitcast (i8* ()* @ifunc_resolver to i32 ()*)
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// PREEMPT: define i32 @func()
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// PREEMPT: declare i32 @ext()
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// METADATA: !{{[0-9]+}} = !{i32 1, !"SemanticInterposition", i32 1}
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// NOMETADATA-NOT: "SemanticInterposition"
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int var;
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extern int ext_var;
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int ifunc(void) __attribute__((ifunc("ifunc_resolver")));
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int func(void) { return 0; }
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int ext(void);
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static void *ifunc_resolver() { return func; }
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int foo() {
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return var + ext_var + ifunc() + func() + ext();
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}
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