Add AIX toolchain and basic linker functionality

Summary:
This patch adds AIX toolchain infrastructure into driver, and enables AIX
system linker invocation with some basic functionality support

Reviewers: daltenty, hubert.reinterpretcast, jasonliu, Xiangling_L

Reviewed By: jasonliu

Subscribers: Xiangling_L, jasonliu, ormris, wuzish, nemanjai, mgorny, kbarton, jfb, jsji, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D68340

Author: steven-wan-yu

clang/lib/Driver/CMakeLists.txt

@@ -30,6 +30,7 @@ add_clang_library(clangDriver
   ToolChains/Arch/Sparc.cpp
   ToolChains/Arch/SystemZ.cpp
   ToolChains/Arch/X86.cpp
+  ToolChains/AIX.cpp
   ToolChains/Ananas.cpp
   ToolChains/AMDGPU.cpp
   ToolChains/AVR.cpp

clang/lib/Driver/Driver.cpp

@@ -8,6 +8,7 @@
 
 #include "clang/Driver/Driver.h"
 #include "InputInfo.h"
+#include "ToolChains/AIX.h"
 #include "ToolChains/AMDGPU.h"
 #include "ToolChains/AVR.h"
 #include "ToolChains/Ananas.h"
@@ -4699,6 +4700,9 @@ const ToolChain &Driver::getToolChain(const ArgList &Args,
   auto &TC = ToolChains[Target.str()];
   if (!TC) {
     switch (Target.getOS()) {
+    case llvm::Triple::AIX:
+      TC = std::make_unique<toolchains::AIX>(*this, Target, Args);
+      break;
     case llvm::Triple::Haiku:
       TC = std::make_unique<toolchains::Haiku>(*this, Target, Args);
       break;

clang/lib/Driver/ToolChains/AIX.cpp

@@ -0,0 +1,101 @@
+//===--- AIX.cpp - AIX ToolChain Implementations ----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "AIX.h"
+#include "Arch/PPC.h"
+#include "CommonArgs.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Options.h"
+#include "clang/Driver/SanitizerArgs.h"
+#include "llvm/Option/ArgList.h"
+
+namespace aix = clang::driver::tools::aix;
+using AIX = clang::driver::toolchains::AIX;
+
+using namespace llvm::opt;
+
+void aix::Linker::ConstructJob(Compilation &C, const JobAction &JA,
+                               const InputInfo &Output,
+                               const InputInfoList &Inputs, const ArgList &Args,
+                               const char *LinkingOutput) const {
+  const AIX &ToolChain = static_cast<const AIX &>(getToolChain());
+  ArgStringList CmdArgs;
+
+  const bool IsArch32Bit = ToolChain.getTriple().isArch32Bit();
+  const bool IsArch64Bit = ToolChain.getTriple().isArch64Bit();
+  // Only support 32 and 64 bit.
+  if (!(IsArch32Bit || IsArch64Bit))
+    llvm_unreachable("Unsupported bit width value.");
+
+  // Force static linking when "-static" is present.
+  if (Args.hasArg(options::OPT_static))
+    CmdArgs.push_back("-bnso");
+
+  // Specify linker output file.
+  assert((Output.isFilename() || Output.isNothing()) && "Invalid output.");
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } 
+
+  // Set linking mode (i.e., 32/64-bit) and the address of
+  // text and data sections based on arch bit width.
+  if (IsArch32Bit) {
+    CmdArgs.push_back("-b32");
+    CmdArgs.push_back("-bpT:0x10000000");
+    CmdArgs.push_back("-bpD:0x20000000");
+  } else {
+    // Must be 64-bit, otherwise asserted already.
+    CmdArgs.push_back("-b64");
+    CmdArgs.push_back("-bpT:0x100000000");
+    CmdArgs.push_back("-bpD:0x110000000");
+  }
+
+  auto getCrt0Basename = [&Args, IsArch32Bit] {
+    // Enable gprofiling when "-pg" is specified.
+    if (Args.hasArg(options::OPT_pg))
+      return IsArch32Bit ? "gcrt0.o" : "gcrt0_64.o";
+    // Enable profiling when "-p" is specified.
+    else if (Args.hasArg(options::OPT_p))
+      return IsArch32Bit ? "mcrt0.o" : "mcrt0_64.o";
+    else
+      return IsArch32Bit ? "crt0.o" : "crt0_64.o";
+  };
+
+  if (!Args.hasArg(options::OPT_nostdlib)) {
+    CmdArgs.push_back(
+        Args.MakeArgString(ToolChain.GetFilePath(getCrt0Basename())));
+  }
+
+  // Specify linker input file(s).
+  AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
+
+  // Add directory to library search path.
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  ToolChain.AddFilePathLibArgs(Args, CmdArgs);
+
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
+    // Support POSIX threads if "-pthreads" or "-pthread" is present.
+    if (Args.hasArg(options::OPT_pthreads, options::OPT_pthread))
+      CmdArgs.push_back("-lpthreads");
+
+    CmdArgs.push_back("-lc");
+  }
+
+  const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
+  C.addCommand(std::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
+}
+
+/// AIX - AIX tool chain which can call ld(1) directly.
+// TODO: Enable direct call to as(1).
+AIX::AIX(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
+    : ToolChain(D, Triple, Args) {
+  getFilePaths().push_back(getDriver().SysRoot + "/usr/lib");
+}
+
+auto AIX::buildLinker() const -> Tool * { return new aix::Linker(*this); }

clang/lib/Driver/ToolChains/AIX.h

@@ -0,0 +1,63 @@
+//===--- AIX.h - AIX ToolChain Implementations ------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AIX_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AIX_H
+
+#include "clang/Driver/Tool.h"
+#include "clang/Driver/ToolChain.h"
+
+namespace clang {
+namespace driver {
+namespace tools {
+
+/// aix -- Directly call system default linker.
+// TODO: Enable direct call to system default assembler.
+namespace aix {
+
+class LLVM_LIBRARY_VISIBILITY Linker : public Tool {
+public:
+  Linker(const ToolChain &TC) : Tool("aix::Linker", "linker", TC) {}
+
+  bool hasIntegratedCPP() const override { return false; }
+  bool isLinkJob() const override { return true; }
+
+  void ConstructJob(Compilation &C, const JobAction &JA,
+                    const InputInfo &Output, const InputInfoList &Inputs,
+                    const llvm::opt::ArgList &TCArgs,
+                    const char *LinkingOutput) const override;
+};
+
+} // end namespace aix
+
+} // end namespace tools
+} // end namespace driver
+} // end namespace clang
+
+namespace clang {
+namespace driver {
+namespace toolchains {
+
+class LLVM_LIBRARY_VISIBILITY AIX : public ToolChain {
+public:
+  AIX(const Driver &D, const llvm::Triple &Triple,
+      const llvm::opt::ArgList &Args);
+
+  bool isPICDefault() const override { return true; }
+  bool isPIEDefault() const override { return false; }
+  bool isPICDefaultForced() const override { return true; }
+
+protected:
+  Tool *buildLinker() const override;
+};
+
+} // end namespace toolchains
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AIX_H