[PATCH] D132843: [RISCV] Ensure target features get passed to the LTO linker for RISC-V

[Lewis Revill via Phabricator via cfe-commits]

lewis-revill created this revision.
lewis-revill added reviewers: efriedma, lenary, jrtc27, asb.
Herald added subscribers: sunshaoce, VincentWu, luke957, ormris, StephenFan, vkmr, frasercrmck, evandro, luismarques, apazos, sameer.abuasal, simoncook, s.egerton, Jim, benna, psnobl, jocewei, PkmX, the_o, brucehoult, MartinMosbeck, rogfer01, steven_wu, edward-jones, zzheng, shiva0217, kito-cheng, niosHD, sabuasal, johnrusso, rbar, hiraditya, arichardson, inglorion.
Herald added a project: All.
lewis-revill requested review of this revision.
Herald added subscribers: cfe-commits, pcwang-thead, eopXD, MaskRay.
Herald added a project: clang.

This patch fixes an issue whereby the LTO linker would not receive any information about target features, so things like architecture extensions would not be accounted for during codegen.

There is perhaps an outstanding question as to why this is required versus obtaining the target features from bitcode. This is the approach I implemented for now, but would be happy to look into whether I can make it work via bitcode if desired.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D132843

Files:
  clang/lib/Driver/ToolChains/Arch/RISCV.cpp
  clang/lib/Driver/ToolChains/Arch/RISCV.h
  clang/lib/Driver/ToolChains/CommonArgs.cpp
  clang/test/Driver/lto.c


Index: clang/test/Driver/lto.c
===================================================================
--- clang/test/Driver/lto.c
+++ clang/test/Driver/lto.c
@@ -155,3 +155,8 @@
 // RISCV-SPEC-ABI-2: "-plugin-opt=-target-abi=ilp32d"
 // RISCV-SPEC-ABI-3: "-plugin-opt=-target-abi=lp64"
 // RISCV-SPEC-ABI-4: "-plugin-opt=-target-abi=lp64f"
+
+// RUN: %clang -target riscv32-unknown-elf %s -fuse-ld=gold -flto -mrelax \
+// RUN:   -### 2>&1 | FileCheck %s --check-prefix=RV32-RELAX-ATTR
+//
+// RV32-RELAX-ATTR: "-plugin-opt=-mattr=+relax"
Index: clang/lib/Driver/ToolChains/CommonArgs.cpp
===================================================================
--- clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -637,6 +637,7 @@
   case llvm::Triple::riscv32:
   case llvm::Triple::riscv64: {
     riscv::addRISCVTargetABIArgs(ToolChain, Args, CmdArgs);
+    riscv::addRISCVTargetFeatureArgs(ToolChain, Args, CmdArgs);
     break;
   }
   }
Index: clang/lib/Driver/ToolChains/Arch/RISCV.h
===================================================================
--- clang/lib/Driver/ToolChains/Arch/RISCV.h
+++ clang/lib/Driver/ToolChains/Arch/RISCV.h
@@ -30,6 +30,10 @@
 void addRISCVTargetABIArgs(const ToolChain &ToolChain,
                            const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs);
+
+void addRISCVTargetFeatureArgs(const ToolChain &ToolChain,
+                               const llvm::opt::ArgList &Args,
+                               llvm::opt::ArgStringList &CmdArgs);
 } // end namespace riscv
 } // namespace tools
 } // end namespace driver
Index: clang/lib/Driver/ToolChains/Arch/RISCV.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Arch/RISCV.cpp
+++ clang/lib/Driver/ToolChains/Arch/RISCV.cpp
@@ -313,3 +313,15 @@
   CmdArgs.push_back(
       Args.MakeArgString(Twine("-plugin-opt=-target-abi=") + ABIName));
 }
+
+void riscv::addRISCVTargetFeatureArgs(const ToolChain &ToolChain,
+                                      const llvm::opt::ArgList &Args,
+                                      llvm::opt::ArgStringList &CmdArgs) {
+  const Driver &D = ToolChain.getDriver();
+
+  // Pass a plugin-opt for each of the target features to the LTO linker.
+  std::vector<StringRef> Features;
+  riscv::getRISCVTargetFeatures(D, ToolChain.getTriple(), Args, Features);
+  for (StringRef F : Features)
+    CmdArgs.push_back(Args.MakeArgString("-plugin-opt=-mattr=" + F));
+}


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D132843.456301.patch
Type: text/x-patch
Size: 2540 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20220829/582b67ca/attachment-0001.bin>