From 13aee94bc710bfa6277c1f07146c714ee65bf2de Mon Sep 17 00:00:00 2001 From: Mircea Trofin Date: Wed, 28 Oct 2020 20:16:51 -0700 Subject: [PATCH] [ThinLTO] Fix empty .llvmcmd sections When passing -lto-embed-bitcode=post-merge-pre-opt, we were getting empty .llvmcmd sections. It turns out that is because the CodeGenOptions::CmdArgs field was only populated when clang saw -fembed-bitcode={all|marker}. This patch always populates the CodeGenOptions::CmdArgs. The overhead of carrying through in memory in all cases is likely negligible in the grand schema of things, and it keeps the using code simple. Differential Revision: https://reviews.llvm.org/D90366 --- clang/lib/Frontend/CompilerInvocation.cpp | 32 ++++++++++++++--------------- clang/test/CodeGen/thinlto_embed_bitcode.ll | 8 ++++++++ 2 files changed, 23 insertions(+), 17 deletions(-) diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index 5175063..2257916 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -1095,23 +1095,21 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK, // FIXME: For backend options that are not yet recorded as function // attributes in the IR, keep track of them so we can embed them in a // separate data section and use them when building the bitcode. - if (Opts.getEmbedBitcode() == CodeGenOptions::Embed_All) { - for (const auto &A : Args) { - // Do not encode output and input. - if (A->getOption().getID() == options::OPT_o || - A->getOption().getID() == options::OPT_INPUT || - A->getOption().getID() == options::OPT_x || - A->getOption().getID() == options::OPT_fembed_bitcode || - A->getOption().matches(options::OPT_W_Group)) - continue; - ArgStringList ASL; - A->render(Args, ASL); - for (const auto &arg : ASL) { - StringRef ArgStr(arg); - Opts.CmdArgs.insert(Opts.CmdArgs.end(), ArgStr.begin(), ArgStr.end()); - // using \00 to separate each commandline options. - Opts.CmdArgs.push_back('\0'); - } + for (const auto &A : Args) { + // Do not encode output and input. + if (A->getOption().getID() == options::OPT_o || + A->getOption().getID() == options::OPT_INPUT || + A->getOption().getID() == options::OPT_x || + A->getOption().getID() == options::OPT_fembed_bitcode || + A->getOption().matches(options::OPT_W_Group)) + continue; + ArgStringList ASL; + A->render(Args, ASL); + for (const auto &arg : ASL) { + StringRef ArgStr(arg); + Opts.CmdArgs.insert(Opts.CmdArgs.end(), ArgStr.begin(), ArgStr.end()); + // using \00 to separate each commandline options. + Opts.CmdArgs.push_back('\0'); } } diff --git a/clang/test/CodeGen/thinlto_embed_bitcode.ll b/clang/test/CodeGen/thinlto_embed_bitcode.ll index 5f7b9f6..6c7e36e 100644 --- a/clang/test/CodeGen/thinlto_embed_bitcode.ll +++ b/clang/test/CodeGen/thinlto_embed_bitcode.ll @@ -17,12 +17,20 @@ ; round-trip through compilation and ensure the objects are the same. ; RUN: %clang -target x86_64-unknown-linux-gnu -O2 -o %t.o -x ir %t1.bc -c -fthinlto-index=%t.o.thinlto.bc -mllvm -lto-embed-bitcode=post-merge-pre-opt ; RUN: llvm-readelf -S %t.o | FileCheck %s --check-prefixes=CHECK-ELF,CHECK-ELF-CMD +; RUN: llvm-objcopy --dump-section=.llvmcmd=%t-embedded.cmd %t.o /dev/null +; RUN: grep x86_64-unknown-linux-gnu %t-embedded.cmd | count 1 ; RUN: llvm-objcopy --dump-section=.llvmbc=%t-embedded.bc %t.o /dev/null ; RUN: llvm-dis %t-embedded.bc -o - | FileCheck %s --check-prefixes=CHECK,CHECK-NOOPT ; We should only need the index and the post-thinlto merged module to generate ; the exact same .o as we originally did. ; RUN: rm %t1.bc %t2.bc ; RUN: %clang -target x86_64-unknown-linux-gnu -O2 -o %t-redo.o -x ir %t-embedded.bc -c -fthinlto-index=%t.o.thinlto.bc -mllvm -lto-embed-bitcode=post-merge-pre-opt -mllvm -thinlto-assume-merged +; +; The resulting .o is almost the same, but the .llvmcmd section would be +; different because of the extra -thinlto-assume-merged. +; A simple, meaningful comparison is to just compare the stripped objects. +; RUN: llvm-strip --strip-all %t-redo.o +; RUN: llvm-strip --strip-all %t.o ; RUN: diff %t-redo.o %t.o ; CHECK-ELF: .text PROGBITS 0000000000000000 [[#%x,OFF:]] [[#%x,SIZE:]] 00 AX 0 -- 2.7.4