forked from OSchip/llvm-project
				
			
		
			
				
	
	
		
			68 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			68 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			C++
		
	
	
	
| // RUN: %clang_cc1 -triple arm64-apple-ios7.0 -target-abi darwinpcs -emit-llvm -o - %s | FileCheck %s
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| // RUN: %clang_cc1 -triple aarch64-linux-gnu -emit-llvm -o - -x c %s | FileCheck %s --check-prefix=CHECK-GNU-C
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| // RUN: %clang_cc1 -triple aarch64-linux-gnu -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-GNU-CXX
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| 
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| // Empty structs are ignored for PCS purposes on Darwin and in C mode elsewhere.
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| // In C++ mode on ELF they consume a register slot though. Functions are
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| // slightly bigger than minimal to make confirmation against actual GCC
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| // behaviour easier.
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| 
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| #if __cplusplus
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| #define EXTERNC extern "C"
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| #else
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| #define EXTERNC
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| #endif
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| 
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| struct Empty {};
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| 
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| // CHECK: define i32 @empty_arg(i32 %a)
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| // CHECK-GNU-C: define i32 @empty_arg(i32 %a)
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| // CHECK-GNU-CXX: define i32 @empty_arg(i8 %e.coerce, i32 %a)
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| EXTERNC int empty_arg(struct Empty e, int a) {
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|   return a;
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| }
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| 
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| // CHECK: define void @empty_ret()
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| // CHECK-GNU-C: define void @empty_ret()
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| // CHECK-GNU-CXX: define void @empty_ret()
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| EXTERNC struct Empty empty_ret() {
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|   struct Empty e;
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|   return e;
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| }
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| 
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| // However, what counts as "empty" is a baroque mess. This is super-empty, it's
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| // ignored even in C++ mode. It also has sizeof == 0, violating C++, but that's
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| // legacy for you:
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| 
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| struct SuperEmpty {
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|   int arr[0];
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| };
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| 
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| // CHECK: define i32 @super_empty_arg(i32 %a)
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| // CHECK-GNU-C: define i32 @super_empty_arg(i32 %a)
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| // CHECK-GNU-CXX: define i32 @super_empty_arg(i32 %a)
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| EXTERNC int super_empty_arg(struct SuperEmpty e, int a) {
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|   return a;
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| }
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| 
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| // This is not empty. It has 0 size but consumes a register slot for GCC.
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| 
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| struct SortOfEmpty {
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|   struct SuperEmpty e;
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| };
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| 
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| // CHECK: define i32 @sort_of_empty_arg(i32 %a)
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| // CHECK-GNU-C: define i32 @sort_of_empty_arg(i32 %a)
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| // CHECK-GNU-CXX: define i32 @sort_of_empty_arg(i8 %e.coerce, i32 %a)
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| EXTERNC int sort_of_empty_arg(struct Empty e, int a) {
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|   return a;
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| }
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| 
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| // CHECK: define void @sort_of_empty_ret()
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| // CHECK-GNU-C: define void @sort_of_empty_ret()
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| // CHECK-GNU-CXX: define void @sort_of_empty_ret()
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| EXTERNC struct SortOfEmpty sort_of_empty_ret() {
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|   struct SortOfEmpty e;
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|   return e;
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| }
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