llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang @llvm/pr-subscribers-clang-driver Author: R (ArcaneNibble) <details> <summary>Changes</summary> This changes the bare-metal driver logic such that it _always_ tries multilib.yaml if it exists, and it falls back to the hardwired/default RISC-V multilib selection only if a multilib.yaml doesn't exist. In contrast, the current behavior is that RISC-V can never use multilib.yaml, but other targets will try it if it exists. The flags `-march=` and `-mabi=` are exposed for multilib.yaml to match on. There is no attempt to help YAML file creators to duplicate the existing hard-wired multilib reuse logic -- they will have to implement it using `Mappings`. This should be backwards-compatible with existing sysroots, as multilib.yaml was previously never used for RISC-V, and the behavior doesn't change after this PR if the file doesn't exist. Some actual use-cases that I want this change for: * `-fno-exceptions` and `-fno-rtti` multilibs for C++ runtimes on small microcontrollers * There's currently no support for rv32e multilibs in the hard-wired logic * I want multilibs where vendor extensions such as the QingKe "XW" compressed opcodes are enabled/disabled. Permutations of features such as this can likely never be handled in hard-wired logic. --- Full diff: https://github.com/llvm/llvm-project/pull/98856.diff 2 Files Affected: - (modified) clang/lib/Driver/ToolChain.cpp (+12) - (modified) clang/lib/Driver/ToolChains/BareMetal.cpp (+9-7) ``````````diff diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp index 85ae4d2a26fee..7cd110a07bd98 100644 --- a/clang/lib/Driver/ToolChain.cpp +++ b/clang/lib/Driver/ToolChain.cpp @@ -9,6 +9,7 @@ #include "clang/Driver/ToolChain.h" #include "ToolChains/Arch/AArch64.h" #include "ToolChains/Arch/ARM.h" +#include "ToolChains/Arch/RISCV.h" #include "ToolChains/Clang.h" #include "ToolChains/CommonArgs.h" #include "ToolChains/Flang.h" @@ -258,6 +259,13 @@ static void getARMMultilibFlags(const Driver &D, } } +static void getRISCVMultilibFlags(const Driver &D, const llvm::Triple &Triple, + const llvm::opt::ArgList &Args, + Multilib::flags_list &Result) { + Result.push_back("-march=" + riscv::getRISCVArch(Args, Triple)); + Result.push_back(("-mabi=" + riscv::getRISCVABI(Args, Triple)).str()); +} + Multilib::flags_list ToolChain::getMultilibFlags(const llvm::opt::ArgList &Args) const { using namespace clang::driver::options; @@ -278,6 +286,10 @@ ToolChain::getMultilibFlags(const llvm::opt::ArgList &Args) const { case llvm::Triple::thumbeb: getARMMultilibFlags(D, Triple, Args, Result); break; + case llvm::Triple::riscv32: + case llvm::Triple::riscv64: + getRISCVMultilibFlags(D, Triple, Args, Result); + break; default: break; } diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp index 852e0442f50a2..95b4051cb74c7 100644 --- a/clang/lib/Driver/ToolChains/BareMetal.cpp +++ b/clang/lib/Driver/ToolChains/BareMetal.cpp @@ -218,17 +218,19 @@ static std::string computeBaseSysRoot(const Driver &D, void BareMetal::findMultilibs(const Driver &D, const llvm::Triple &Triple, const ArgList &Args) { DetectedMultilibs Result; - if (isRISCVBareMetal(Triple)) { + // Look for a multilib.yaml before trying target-specific hardwired logic. + // If it exists, always do what it specifies. + llvm::SmallString<128> MultilibPath(computeBaseSysRoot(D, Triple)); + llvm::sys::path::append(MultilibPath, MultilibFilename); + if (D.getVFS().exists(MultilibPath)) { + findMultilibsFromYAML(*this, D, MultilibPath, Args, Result); + SelectedMultilibs = Result.SelectedMultilibs; + Multilibs = Result.Multilibs; + } else if (isRISCVBareMetal(Triple)) { if (findRISCVMultilibs(D, Triple, Args, Result)) { SelectedMultilibs = Result.SelectedMultilibs; Multilibs = Result.Multilibs; } - } else { - llvm::SmallString<128> MultilibPath(computeBaseSysRoot(D, Triple)); - llvm::sys::path::append(MultilibPath, MultilibFilename); - findMultilibsFromYAML(*this, D, MultilibPath, Args, Result); - SelectedMultilibs = Result.SelectedMultilibs; - Multilibs = Result.Multilibs; } } `````````` </details> https://github.com/llvm/llvm-project/pull/98856 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
