0404605dda
Before this change, we would pass all non-HFA record arguments on Windows with byval. Byval often blocks optimizations and results in bad code generation. Windows now uses the existing workaround that other x86_32 platforms use. I also expanded the workaround to handle C++ records with constructors on Windows. On non-Windows platforms, we have to keep generating the same LLVM IR prototypes if we want our bitcode to be ABI compatible. Otherwise we will encounter mismatch issues like PR21573. Essentially fixes PR27522 in Clang instead of LLVM. Reviewers: hans Differential Revision: http://reviews.llvm.org/D19756 llvm-svn: 268261
45 lines
1.4 KiB
C++
45 lines
1.4 KiB
C++
// RUN: %clang_cc1 -triple i386-pc-win32 -emit-llvm %s -o - | FileCheck %s
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// PR15768
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// A trivial 20 byte struct is returned indirectly and taken as byval.
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struct S {
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S();
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int a, b, c, d, e;
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};
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struct C {
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S variadic_sret(const char *f, ...);
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S __cdecl cdecl_sret();
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S __cdecl byval_and_sret(S a);
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int c;
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};
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S C::variadic_sret(const char *f, ...) { return S(); }
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S C::cdecl_sret() { return S(); }
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S C::byval_and_sret(S a) { return S(); }
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// CHECK: define void @"\01?variadic_sret@C@@QAA?AUS@@PBDZZ"(%struct.C* %this, %struct.S* noalias sret %agg.result, i8* %f, ...)
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// CHECK: define void @"\01?cdecl_sret@C@@QAA?AUS@@XZ"(%struct.C* %this, %struct.S* noalias sret %agg.result)
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// CHECK: define void @"\01?byval_and_sret@C@@QAA?AUS@@U2@@Z"(%struct.C* %this, %struct.S* noalias sret %agg.result, %struct.S* byval align 4 %a)
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int main() {
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C c;
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c.variadic_sret("asdf");
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c.cdecl_sret();
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c.byval_and_sret(S());
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}
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// CHECK-LABEL: define i32 @main()
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// CHECK: call void {{.*}} @"\01?variadic_sret@C@@QAA?AUS@@PBDZZ"
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// CHECK: call void @"\01?cdecl_sret@C@@QAA?AUS@@XZ"
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// CHECK: call void @"\01?byval_and_sret@C@@QAA?AUS@@U2@@Z"
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// __fastcall has similar issues.
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struct A {
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S __fastcall f(int x);
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};
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S A::f(int x) {
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return S();
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}
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// CHECK-LABEL: define x86_fastcallcc void @"\01?f@A@@QAI?AUS@@H@Z"(%struct.A* inreg %this, %struct.S* inreg noalias sret %agg.result, i32 %x)
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