From 0b5b5abb4c632c8527c0ba5c6d4e0ea0cb0ba463 Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Fri, 10 May 2019 02:08:21 +0000 Subject: [PATCH] Change -gz and -Wa,--compress-debug-sections to use gABI compression (SHF_COMPRESSED) Since July 15, 2015 (binutils-gdb commit 19a7fe52ae3d0971e67a134bcb1648899e21ae1c, included in 2.26), gas --compress-debug-sections=zlib (gcc -gz) means zlib-gabi: SHF_COMPRESSED. Before that it meant zlib-gnu (.zdebug). clang's -gz was introduced in rC306115 (Jun 2017) to indicate zlib-gnu. It is 2019 now and it is not unreasonable to assume users of the new feature to have new linkers (ld.bfd/gold >= 2.26, lld >= rLLD273661). Change clang's default accordingly to improve standard conformance. zlib-gnu becomes out of fashion and gets poorer toolchain support. Its mangled names confuse tools and are more likely to cause problems. Reviewed By: compnerd Differential Revision: https://reviews.llvm.org/D61689 llvm-svn: 360403 --- clang/docs/ReleaseNotes.rst | 5 ++++- clang/lib/Frontend/CompilerInvocation.cpp | 3 +-- clang/tools/driver/cc1as_main.cpp | 3 +-- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 1f09655027fc4..cf15a024fca33 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -77,7 +77,10 @@ Modified Compiler Flags - `clang -dumpversion` now returns the version of Clang itself. -- ... +- On ELF, ``-gz`` now defaults to ``-gz=zlib``. It produces ``SHF_COMPRESSED`` + style compression of debug information. GNU binutils 2.26 or newer, or lld is + required to link produced object files. Use ``-gz=zlib-gnu`` to get the old + behavior. New Pragmas in Clang -------------------- diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index 39b4122d752a8..cf68235954942 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -1053,8 +1053,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK, if (const Arg *A = Args.getLastArg(OPT_compress_debug_sections, OPT_compress_debug_sections_EQ)) { if (A->getOption().getID() == OPT_compress_debug_sections) { - // TODO: be more clever about the compression type auto-detection - Opts.setCompressDebugSections(llvm::DebugCompressionType::GNU); + Opts.setCompressDebugSections(llvm::DebugCompressionType::Z); } else { auto DCT = llvm::StringSwitch(A->getValue()) .Case("none", llvm::DebugCompressionType::None) diff --git a/clang/tools/driver/cc1as_main.cpp b/clang/tools/driver/cc1as_main.cpp index c0334609be5f7..f9c25399b372c 100644 --- a/clang/tools/driver/cc1as_main.cpp +++ b/clang/tools/driver/cc1as_main.cpp @@ -221,8 +221,7 @@ bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts, if (const Arg *A = Args.getLastArg(OPT_compress_debug_sections, OPT_compress_debug_sections_EQ)) { if (A->getOption().getID() == OPT_compress_debug_sections) { - // TODO: be more clever about the compression type auto-detection - Opts.CompressDebugSections = llvm::DebugCompressionType::GNU; + Opts.CompressDebugSections = llvm::DebugCompressionType::Z; } else { Opts.CompressDebugSections = llvm::StringSwitch(A->getValue())