From ca65969c3ea0ad3db31e8b3646b960c75ef5f6c8 Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Sun, 5 Feb 2023 10:46:43 -0800 Subject: [PATCH] [AArch64] Unconditionally use DW_EH_PE_indirect|DW_EH_PE_pcrel personality/lsda/ttype encodings For -fno-pic, without DW_EH_PE_indirect, the personality routine pointer in a CIE needs an R_AARCH64_ABS64 relocation. In common configurations that `__gcc_personality_v0` is defined in a shared object, this will lead to a discouraged canonical PLT entry, or, if `ld.lld -z notext` (betwen D122459 and D143136), a dynamic R_AARCH64_ABS64 relocation with an incorrect offset: https://github.com/llvm/llvm-project/issues/60392 Since GCC uses DW_EH_PE_indirect for -fno-pic code (the behavior hasn't changed since the initial port in 2012), let's follow suit by simplifying the code. ( For tiny and small code models, we use DW_EH_PE_sdata8 instead of GCC's DW_EH_PE_sdata4. This is a deliberate choice to support personality-.eh_frame offset > 2GiB. This is unneeded for small code model since "Max text segment size < 2GiB" but making `-fno-pic -mcmodel={tiny,small}` different seems unnecessary: the scenarios that uses both -fno-pic and C++ exceptions have been increasingly rare now, so there is little advantage optimizing for the little size saving with code complexity. ) --- Two clang/test/Interpreter tests would fail without 6747fc07d1aa94e22622e278e5a02ba70675ac9b ([ORC] Use JITLink as the default linker for LLJIT on Linux/arm64.) Reviewed By: MatzeB Differential Revision: https://reviews.llvm.org/D143039 --- llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp | 28 +++++++--------------- llvm/test/CodeGen/AArch64/arm64-big-endian-eh.ll | 3 ++- llvm/test/CodeGen/AArch64/pic-eh-stubs.ll | 1 + .../test/DebugInfo/AArch64/eh_frame_personality.ll | 2 +- .../CodeGenPrepare/AArch64/large-offset-gep.ll | 4 ++-- 5 files changed, 14 insertions(+), 24 deletions(-) diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp index 39f7ee7..bdb328f 100644 --- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp +++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp @@ -182,26 +182,14 @@ void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx, // The small model guarantees static code/data size < 4GB, but not where it // will be in memory. Most of these could end up >2GB away so even a signed // pc-relative 32-bit address is insufficient, theoretically. - if (isPositionIndependent()) { - // ILP32 uses sdata4 instead of sdata8 - if (TgtM.getTargetTriple().getEnvironment() == Triple::GNUILP32) { - PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | - dwarf::DW_EH_PE_sdata4; - LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; - TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | - dwarf::DW_EH_PE_sdata4; - } else { - PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | - dwarf::DW_EH_PE_sdata8; - LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8; - TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | - dwarf::DW_EH_PE_sdata8; - } - } else { - PersonalityEncoding = dwarf::DW_EH_PE_absptr; - LSDAEncoding = dwarf::DW_EH_PE_absptr; - TTypeEncoding = dwarf::DW_EH_PE_absptr; - } + // + // Use DW_EH_PE_indirect even for -fno-pic to avoid copy relocations. + LSDAEncoding = dwarf::DW_EH_PE_pcrel | + (TgtM.getTargetTriple().getEnvironment() == Triple::GNUILP32 + ? dwarf::DW_EH_PE_sdata4 + : dwarf::DW_EH_PE_sdata8); + PersonalityEncoding = LSDAEncoding | dwarf::DW_EH_PE_indirect; + TTypeEncoding = LSDAEncoding | dwarf::DW_EH_PE_indirect; break; case Triple::lanai: LSDAEncoding = dwarf::DW_EH_PE_absptr; diff --git a/llvm/test/CodeGen/AArch64/arm64-big-endian-eh.ll b/llvm/test/CodeGen/AArch64/arm64-big-endian-eh.ll index c6f955f0..6c54cec 100644 --- a/llvm/test/CodeGen/AArch64/arm64-big-endian-eh.ll +++ b/llvm/test/CodeGen/AArch64/arm64-big-endian-eh.ll @@ -71,5 +71,6 @@ declare void @_ZSt9terminatev() ; CHECK-LABEL: Contents of section .eh_frame: ; CHECK-NEXT: {{^ 0000}} ; CHECK-NEXT: {{^ 0010}} -; CHECK-NEXT: 0000 0000001c +; CHECK-NEXT: 0020 0000000c 00440e10 9e040000 0000001c .....D.......... +; CHECK-NEXT: 0030 00000000 017a504c 5200017c 1e0b9c00 .....zPLR..|.... diff --git a/llvm/test/CodeGen/AArch64/pic-eh-stubs.ll b/llvm/test/CodeGen/AArch64/pic-eh-stubs.ll index 3d072bc..bdb557e 100644 --- a/llvm/test/CodeGen/AArch64/pic-eh-stubs.ll +++ b/llvm/test/CodeGen/AArch64/pic-eh-stubs.ll @@ -1,3 +1,4 @@ +; RUN: llc -mtriple=aarch64-none-linux-gnu -relocation-model=static -simplifycfg-require-and-preserve-domtree=1 -o - %s | FileCheck %s ; RUN: llc -mtriple=aarch64-none-linux-gnu -relocation-model=pic -simplifycfg-require-and-preserve-domtree=1 -o - %s | FileCheck %s ; RUN: llc -mtriple=aarch64_be-none-linux-gnu -relocation-model=pic -simplifycfg-require-and-preserve-domtree=1 -o - %s | FileCheck %s diff --git a/llvm/test/DebugInfo/AArch64/eh_frame_personality.ll b/llvm/test/DebugInfo/AArch64/eh_frame_personality.ll index 912ebf1..2ee65a8 100644 --- a/llvm/test/DebugInfo/AArch64/eh_frame_personality.ll +++ b/llvm/test/DebugInfo/AArch64/eh_frame_personality.ll @@ -17,7 +17,7 @@ clean: ; CHECK: Contents of section .eh_frame: ; CHECK: 0000 1c000000 00000000 017a504c 5200017c .........zPLR..| -; CHECK: 0010 1e0b0000 00000000 00000000 1b0c1f00 ................ +; CHECK: 0010 1e0b9c00 00000000 0000001c 1b0c1f00 ................ ; Don't really care about the rest: diff --git a/llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll b/llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll index 9d8ef90..301bf66b 100644 --- a/llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll +++ b/llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll @@ -138,8 +138,8 @@ define void @test4(i32 %n) uwtable personality ptr @__FrameHandler { ; CHECK-LABEL: test4: ; CHECK: .Lfunc_begin0: ; CHECK-NEXT: .cfi_startproc -; CHECK-NEXT: .cfi_personality 0, __FrameHandler -; CHECK-NEXT: .cfi_lsda 0, .Lexception0 +; CHECK-NEXT: .cfi_personality 156, DW.ref.__FrameHandler +; CHECK-NEXT: .cfi_lsda 28, .Lexception0 ; CHECK-NEXT: // %bb.0: // %entry ; CHECK-NEXT: stp x30, x21, [sp, #-32]! // 16-byte Folded Spill ; CHECK-NEXT: .cfi_def_cfa_offset 32 -- 2.7.4