c86899d2d2
In MSVC, when `/d1initall` is enabled, `__declspec(no_init_all)` can be applied to a type to suppress auto-initialization for all instances of that type or to a function to suppress auto-initialization for all locals within that function. This change does the same for Clang, except that it applies to the `-ftrivial-auto-var-init` flag instead. NOTE: I did not add a Clang-specific spelling for this but would be happy to make a followup PR if folks are interested in that.
59 lines
1.9 KiB
C++
59 lines
1.9 KiB
C++
// RUN: %clang_cc1 -std=c++14 -triple x86_64-unknown-unknown -fblocks -fdeclspec -ftrivial-auto-var-init=zero %s -emit-llvm -o - | FileCheck %s
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struct S { char c; };
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class C { char c; };
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enum class E { ZERO };
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union U { char c; int i; };
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struct __declspec(no_init_all) NoInitS { char c; };
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class __declspec(no_init_all) NoInitC { char c; };
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enum class __declspec(no_init_all) NoInitE { ZERO };
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union __declspec(no_init_all) NoInitU { char c; int i; };
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extern "C" {
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void test_no_attr() {
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// CHECK-LABEL: @test_no_attr()
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// CHECK-NEXT: entry:
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// CHECK-NEXT: %s = alloca %struct.S, align 1
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// CHECK-NEXT: %c = alloca %class.C, align 1
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// CHECK-NEXT: %e = alloca i32, align 4
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// CHECK-NEXT: %u = alloca %union.U, align 4
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// CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 1 %s, i8 0, i64 1, i1 false)
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// CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 1 %c, i8 0, i64 1, i1 false)
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// CHECK-NEXT: store i32 0, ptr %e, align 4
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// CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 4 %u, i8 0, i64 4, i1 false)
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// CHECK-NEXT ret void
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S s;
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C c;
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E e;
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U u;
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}
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void __declspec(no_init_all) test_attr_on_function() {
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// CHECK-LABEL: @test_attr_on_function()
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// CHECK-NEXT: entry:
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// CHECK-NEXT: %s = alloca %struct.S, align 1
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// CHECK-NEXT: %c = alloca %class.C, align 1
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// CHECK-NEXT: %e = alloca i32, align 4
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// CHECK-NEXT: %u = alloca %union.U, align 4
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// CHECK-NEXT: ret void
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S s;
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C c;
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E e;
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U u;
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}
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void test_attr_on_decl() {
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// CHECK-LABEL: @test_attr_on_decl()
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// CHECK-NEXT: entry:
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// CHECK-NEXT: %s = alloca %struct.NoInitS, align 1
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// CHECK-NEXT: %c = alloca %class.NoInitC, align 1
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// CHECK-NEXT: %e = alloca i32, align 4
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// CHECK-NEXT: %u = alloca %union.NoInitU, align 4
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// CHECK-NEXT: ret void
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NoInitS s;
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NoInitC c;
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NoInitE e;
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NoInitU u;
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}
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} |