Author: Simon Tatham Date: 2025-07-18T09:34:42+01:00 New Revision: 3ce06b8c2196be6368f0e06862ac1849379cce41
URL: https://github.com/llvm/llvm-project/commit/3ce06b8c2196be6368f0e06862ac1849379cce41 DIFF: https://github.com/llvm/llvm-project/commit/3ce06b8c2196be6368f0e06862ac1849379cce41.diff LOG: [Clang][Driver] Expose relocation model as multilib flags (#149132) If a multilib collection contains libraries built for different methods of accessing global data (via absolute address, or via a GOT in -fPIC style, or as an offset from a fixed register in Arm -frwpi style), then `multilib.yaml` will need to know which relocation model an application is using in order to select the right library. Even if a multilib collection only supports one relocation model, it's still useful for `multilib.yaml` to be able to tell if the user has selected the right one, so as to give a useful error message if they haven't, instead of silently selecting a library that won't work. In this commit we determine the PIC / ROPI / RWPI status using the existing logic in `ParsePICArgs`, and translate it back into a canonical set of multilib selection flags. Added: Modified: clang/lib/Driver/ToolChain.cpp clang/test/Driver/print-multi-selection-flags.c Removed: ################################################################################ diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp index 3f9b808b2722e..481f575518b93 100644 --- a/clang/lib/Driver/ToolChain.cpp +++ b/clang/lib/Driver/ToolChain.cpp @@ -258,10 +258,10 @@ static void getAArch64MultilibFlags(const Driver &D, processMultilibCustomFlags(Result, Args); } -static void getARMMultilibFlags(const Driver &D, - const llvm::Triple &Triple, - const llvm::opt::ArgList &Args, - Multilib::flags_list &Result) { +static void getARMMultilibFlags(const Driver &D, const llvm::Triple &Triple, + llvm::Reloc::Model RelocationModel, + const llvm::opt::ArgList &Args, + Multilib::flags_list &Result) { std::vector<StringRef> Features; llvm::ARM::FPUKind FPUKind = tools::arm::getARMTargetFeatures( D, Triple, Args, Features, false /*ForAs*/, true /*ForMultilib*/); @@ -304,6 +304,18 @@ static void getARMMultilibFlags(const Driver &D, llvm_unreachable("Invalid float ABI"); } + if (RelocationModel == llvm::Reloc::ROPI || + RelocationModel == llvm::Reloc::ROPI_RWPI) + Result.push_back("-fropi"); + else + Result.push_back("-fno-ropi"); + + if (RelocationModel == llvm::Reloc::RWPI || + RelocationModel == llvm::Reloc::ROPI_RWPI) + Result.push_back("-frwpi"); + else + Result.push_back("-fno-rwpi"); + const Arg *BranchProtectionArg = Args.getLastArgNoClaim(options::OPT_mbranch_protection_EQ); if (BranchProtectionArg) { @@ -344,6 +356,18 @@ ToolChain::getMultilibFlags(const llvm::opt::ArgList &Args) const { const llvm::Triple Triple(ComputeEffectiveClangTriple(Args)); Result.push_back("--target=" + Triple.str()); + // A diff erence of relocation model (absolutely addressed data, PIC, Arm + // ROPI/RWPI) is likely to change whether a particular multilib variant is + // compatible with a given link. Determine the relocation model of the + // current link, so as to add appropriate multilib flags. + llvm::Reloc::Model RelocationModel; + unsigned PICLevel; + bool IsPIE; + { + RegisterEffectiveTriple TripleRAII(*this, Triple); + std::tie(RelocationModel, PICLevel, IsPIE) = ParsePICArgs(*this, Args); + } + switch (Triple.getArch()) { case llvm::Triple::aarch64: case llvm::Triple::aarch64_32: @@ -354,7 +378,7 @@ ToolChain::getMultilibFlags(const llvm::opt::ArgList &Args) const { case llvm::Triple::armeb: case llvm::Triple::thumb: case llvm::Triple::thumbeb: - getARMMultilibFlags(D, Triple, Args, Result); + getARMMultilibFlags(D, Triple, RelocationModel, Args, Result); break; case llvm::Triple::riscv32: case llvm::Triple::riscv64: @@ -376,6 +400,12 @@ ToolChain::getMultilibFlags(const llvm::opt::ArgList &Args) const { else Result.push_back("-fexceptions"); + if (RelocationModel == llvm::Reloc::PIC_) + Result.push_back(IsPIE ? (PICLevel > 1 ? "-fPIE" : "-fpie") + : (PICLevel > 1 ? "-fPIC" : "-fpic")); + else + Result.push_back("-fno-pic"); + // Sort and remove duplicates. std::sort(Result.begin(), Result.end()); Result.erase(llvm::unique(Result), Result.end()); diff --git a/clang/test/Driver/print-multi-selection-flags.c b/clang/test/Driver/print-multi-selection-flags.c index 5f9383fbed8f4..8cf8f04bb6b48 100644 --- a/clang/test/Driver/print-multi-selection-flags.c +++ b/clang/test/Driver/print-multi-selection-flags.c @@ -107,3 +107,22 @@ // CHECK-AARCH64-MULTILIB-CUSTOM-FLAG: --target=aarch64-unknown-none-eabi // CHECK-MULTILIB-CUSTOM-FLAG-DAG: -fmultilib-flag=foo // CHECK-MULTILIB-CUSTOM-FLAG-DAG: -fmultilib-flag=bar + +// RUN: %clang -multi-lib-config=%S/Inputs/multilib/empty.yaml -print-multi-flags-experimental --target=arm-none-eabi -march=armv7a -fropi | FileCheck --check-prefixes=CHECK-ROPI,CHECK-NO-RWPI,CHECK-NO-PIC %s +// RUN: %clang -multi-lib-config=%S/Inputs/multilib/empty.yaml -print-multi-flags-experimental --target=arm-none-eabi -march=armv7a -frwpi | FileCheck --check-prefixes=CHECK-NO-ROPI,CHECK-RWPI,CHECK-NO-PIC %s +// RUN: %clang -multi-lib-config=%S/Inputs/multilib/empty.yaml -print-multi-flags-experimental --target=arm-none-eabi -march=armv7a -fropi -frwpi | FileCheck --check-prefixes=CHECK-ROPI,CHECK-RWPI,CHECK-NO-PIC %s +// RUN: %clang -multi-lib-config=%S/Inputs/multilib/empty.yaml -print-multi-flags-experimental --target=arm-none-eabi -march=armv7a -fno-ropi -fno-rwpi | FileCheck --check-prefixes=CHECK-NO-ROPI,CHECK-NO-RWPI,CHECK-NO-PIC %s +// RUN: %clang -multi-lib-config=%S/Inputs/multilib/empty.yaml -print-multi-flags-experimental --target=arm-none-eabi -march=armv7a | FileCheck --check-prefixes=CHECK-NO-ROPI,CHECK-NO-RWPI,CHECK-NO-PIC %s +// RUN: %clang -multi-lib-config=%S/Inputs/multilib/empty.yaml -print-multi-flags-experimental --target=arm-none-eabi -march=armv7a -fpic | FileCheck --check-prefixes=CHECK-NO-ROPI,CHECK-NO-RWPI,CHECK-PIC1 %s +// RUN: %clang -multi-lib-config=%S/Inputs/multilib/empty.yaml -print-multi-flags-experimental --target=arm-none-eabi -march=armv7a -fPIC | FileCheck --check-prefixes=CHECK-NO-ROPI,CHECK-NO-RWPI,CHECK-PIC2 %s +// RUN: %clang -multi-lib-config=%S/Inputs/multilib/empty.yaml -print-multi-flags-experimental --target=arm-none-eabi -march=armv7a -fpie | FileCheck --check-prefixes=CHECK-NO-ROPI,CHECK-NO-RWPI,CHECK-PIE1 %s +// RUN: %clang -multi-lib-config=%S/Inputs/multilib/empty.yaml -print-multi-flags-experimental --target=arm-none-eabi -march=armv7a -fPIE | FileCheck --check-prefixes=CHECK-NO-ROPI,CHECK-NO-RWPI,CHECK-PIE2 %s +// CHECK-PIC2: -fPIC +// CHECK-PIE2: -fPIE +// CHECK-NO-PIC: -fno-pic +// CHECK-NO-ROPI: -fno-ropi +// CHECK-NO-RWPI: -fno-rwpi +// CHECK-PIC1: -fpic +// CHECK-PIE1: -fpie +// CHECK-ROPI: -fropi +// CHECK-RWPI: -frwpi _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
