From 80a4e6fd31a06143b83947785ea3bd5c04344ea6 Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Fri, 22 Jul 2022 17:16:41 -0700 Subject: [PATCH] [Driver] Error for -gsplit-dwarf with RISC-V linker relaxation -gsplit-dwarf produces a .dwo file which will not be processed by the linker. If .dwo files contain relocations, they will not be resolved. Therefore the practice is that .dwo files do not contain relocations. Address ranges and location description need to use forms/entry kinds indexing into .debug_addr (DW_FORM_addrx/DW_RLE_startx_endx/etc), which is currently not implemented. There is a difficult-to-read MC error with -gsplit-dwarf with RISC-V for both -mrelax and -mno-relax. ``` % clang --target=riscv64-linux-gnu -g -gsplit-dwarf -c a.c error: A dwo section may not contain relocations ``` We expect to fix -mno-relax soon, so report a driver error for -mrelax for now. Link: https://github.com/llvm/llvm-project/issues/56642 Reviewed By: compnerd, kito-cheng Differential Revision: https://reviews.llvm.org/D130190 --- clang/include/clang/Basic/DiagnosticDriverKinds.td | 3 +++ clang/lib/Driver/ToolChains/Arch/RISCV.cpp | 12 ++++++++++-- clang/lib/Driver/ToolChains/Clang.cpp | 4 +--- clang/lib/Driver/ToolChains/Clang.h | 6 ++++++ clang/test/Driver/riscv-features.c | 7 +++++++ 5 files changed, 27 insertions(+), 5 deletions(-) diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td index 3c5f7e087de8..2f600d28fea0 100644 --- a/clang/include/clang/Basic/DiagnosticDriverKinds.td +++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td @@ -682,4 +682,7 @@ def err_drv_invalid_empty_dxil_validator_version : Error< def warn_drv_sarif_format_unstable : Warning< "diagnostic formatting in SARIF mode is currently unstable">, InGroup>; + +def err_drv_riscv_unsupported_with_linker_relaxation : Error< + "%0 is unsupported with RISC-V linker relaxation (-mrelax)">; } diff --git a/clang/lib/Driver/ToolChains/Arch/RISCV.cpp b/clang/lib/Driver/ToolChains/Arch/RISCV.cpp index 8a8ed20986c5..de6e045a9447 100644 --- a/clang/lib/Driver/ToolChains/Arch/RISCV.cpp +++ b/clang/lib/Driver/ToolChains/Arch/RISCV.cpp @@ -7,6 +7,7 @@ //===----------------------------------------------------------------------===// #include "RISCV.h" +#include "../Clang.h" #include "ToolChains/CommonArgs.h" #include "clang/Basic/CharInfo.h" #include "clang/Driver/Driver.h" @@ -137,10 +138,17 @@ void riscv::getRISCVTargetFeatures(const Driver &D, const llvm::Triple &Triple, Features.push_back("+reserve-x31"); // -mrelax is default, unless -mno-relax is specified. - if (Args.hasFlag(options::OPT_mrelax, options::OPT_mno_relax, true)) + if (Args.hasFlag(options::OPT_mrelax, options::OPT_mno_relax, true)) { Features.push_back("+relax"); - else + // -gsplit-dwarf -mrelax requires DW_AT_high_pc/DW_AT_ranges/... indexing + // into .debug_addr, which is currently not implemented. + Arg *A; + if (getDebugFissionKind(D, Args, A) != DwarfFissionKind::None) + D.Diag(clang::diag::err_drv_riscv_unsupported_with_linker_relaxation) + << A->getAsString(Args); + } else { Features.push_back("-relax"); + } // GCC Compatibility: -mno-save-restore is default, unless -msave-restore is // specified. diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index 33e3fe267c23..3044c2d92d21 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -4034,9 +4034,7 @@ static void RenderDiagnosticsOptions(const Driver &D, const ArgList &Args, options::OPT_fno_spell_checking); } -enum class DwarfFissionKind { None, Split, Single }; - -static DwarfFissionKind getDebugFissionKind(const Driver &D, +DwarfFissionKind tools::getDebugFissionKind(const Driver &D, const ArgList &Args, Arg *&Arg) { Arg = Args.getLastArg(options::OPT_gsplit_dwarf, options::OPT_gsplit_dwarf_EQ, options::OPT_gno_split_dwarf); diff --git a/clang/lib/Driver/ToolChains/Clang.h b/clang/lib/Driver/ToolChains/Clang.h index 37263efd57a5..5209c6687599 100644 --- a/clang/lib/Driver/ToolChains/Clang.h +++ b/clang/lib/Driver/ToolChains/Clang.h @@ -198,6 +198,12 @@ class LLVM_LIBRARY_VISIBILITY LinkerWrapper final : public Tool { const char *LinkingOutput) const override; }; +enum class DwarfFissionKind { None, Split, Single }; + +DwarfFissionKind getDebugFissionKind(const Driver &D, + const llvm::opt::ArgList &Args, + llvm::opt::Arg *&Arg); + } // end namespace tools } // end namespace driver diff --git a/clang/test/Driver/riscv-features.c b/clang/test/Driver/riscv-features.c index 3068ae74760b..37b6f8647d49 100644 --- a/clang/test/Driver/riscv-features.c +++ b/clang/test/Driver/riscv-features.c @@ -35,3 +35,10 @@ // RUN: not %clang -cc1 -triple riscv64-unknown-elf -target-feature +e 2>&1 | FileCheck %s -check-prefix=RV64-WITH-E // RV64-WITH-E: error: invalid feature combination: standard user-level extension 'e' requires 'rv32' + +// RUN: not %clang -c --target=riscv64-linux-gnu -gsplit-dwarf %s 2>&1 | FileCheck %s --check-prefix=ERR-SPLIT-DWARF +// RUN: not %clang -c --target=riscv64 -gsplit-dwarf=single %s 2>&1 | FileCheck %s --check-prefix=ERR-SPLIT-DWARF +// RUN: %clang -### -c --target=riscv64 -mno-relax -g -gsplit-dwarf %s 2>&1 | FileCheck %s --check-prefix=SPLIT-DWARF + +// ERR-SPLIT-DWARF: error: -gsplit-dwarf{{.*}} is unsupported with RISC-V linker relaxation (-mrelax) +// SPLIT-DWARF: "-split-dwarf-file"