e8c0ae60d7
Summary: Part of the work done in the `libc` project is to provide host services for things like `printf` or `malloc`, or generally any syscall-like behaviour. This scheme works by emitting an externally visible global called `__llvm_libc_rpc_client` that the host runtime can pick up to get a handle to the global memory associated with the client. We use the presence of this symbol to indicate whether or not we need to run an RPC server. Normally, this symbol is only present if something requiring an RPC server was linked in, such as `printf`. However, if this call to `printf` was subsequently optimizated out, the symbol would remain and cannot be removed (rightfully so) because of its linkage. This patch adds a special-case optimization to remove this symbol so we can indicate that an RPC server is no longer needed. This patch puts this logic in `OpenMPOpt` as the most readily available place for it. In the future, we should think how to move this somewhere more generic. Furthermore, we use a hard-coded runtime name (which isn't uncommon given all the other magic symbol names). But it might be nice to abstract that part away.
30 lines
1.3 KiB
LLVM
30 lines
1.3 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --function-signature --check-globals
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; RUN: opt -S -passes=openmp-opt-postlink < %s | FileCheck %s --check-prefix=POSTLINK
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; RUN: opt -S -passes=openmp-opt < %s | FileCheck %s --check-prefix=PRELINK
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@client = internal addrspace(1) global i32 zeroinitializer, align 8
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@__llvm_libc_rpc_client = protected local_unnamed_addr addrspace(1) global ptr addrspacecast (ptr addrspace(1) @client to ptr), align 8
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;.
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; POSTLINK-NOT: @[[CLIENT:[a-zA-Z0-9_$"\\.-]+]] = internal addrspace(1) global i32 0, align 8
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; POSTLINK-NOT: @[[__LLVM_LIBC_RPC_CLIENT:[a-zA-Z0-9_$"\\.-]+]] = protected local_unnamed_addr addrspace(1) global ptr addrspacecast (ptr addrspace(1) @client to ptr), align 8
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;.
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; PRELINK: @[[CLIENT:[a-zA-Z0-9_$"\\.-]+]] = internal addrspace(1) global i32 0, align 8
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; PRELINK: @[[__LLVM_LIBC_RPC_CLIENT:[a-zA-Z0-9_$"\\.-]+]] = protected local_unnamed_addr addrspace(1) global ptr addrspacecast (ptr addrspace(1) @client to ptr), align 8
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;.
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define void @a() {
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; POSTLINK-LABEL: define {{[^@]+}}@a() {
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; POSTLINK-NEXT: ret void
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;
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; PRELINK-LABEL: define {{[^@]+}}@a() {
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; PRELINK-NEXT: ret void
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;
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ret void
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}
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!llvm.module.flags = !{!0, !1, !2}
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!0 = !{i32 1, !"wchar_size", i32 4}
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!1 = !{i32 7, !"openmp", i32 50}
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!2 = !{i32 7, !"openmp-device", i32 50}
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