[Clang][NFC] Introduce --offloadlib positive flag for nogpulib and alias to --no-offloadlib (llvm#126567)

Summary:
We support `nogpulib` to disable implicit libraries. In the future we
will want to change the default linking of these libraries based on the
user language. This patch just introduces a positive variant so now we
can do `-nogpulib -gpulib` to disable it.

Later patch will make the default a variable in the ROCmToolChain
depending on the target languages.

Author: jhuber6

clang/include/clang/Driver/Options.td

@@ -5618,10 +5618,18 @@ def nogpuinc : Flag<["-"], "nogpuinc">, Group<IncludePath_Group>,
 def nohipwrapperinc : Flag<["-"], "nohipwrapperinc">, Group<IncludePath_Group>,
   HelpText<"Do not include the default HIP wrapper headers and include paths">;
 def : Flag<["-"], "nocudainc">, Alias<nogpuinc>;
-def nogpulib : Flag<["-"], "nogpulib">, MarshallingInfoFlag<LangOpts<"NoGPULib">>,
-  Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
-  HelpText<"Do not link device library for CUDA/HIP device compilation">;
-def : Flag<["-"], "nocudalib">, Alias<nogpulib>;
+def no_offloadlib
+    : Flag<["--"], "no-offloadlib">,
+      MarshallingInfoFlag<LangOpts<"NoGPULib">>,
+      Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
+      HelpText<"Do not link device library for CUDA/HIP device compilation">;
+def offloadlib : Flag<["--"], "offloadlib">,
+                 Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
+                 HelpText<"Link device libraries for GPU device compilation">;
+def : Flag<["-"], "nogpulib">,
+      Alias<no_offloadlib>,
+      Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>;
+def : Flag<["-"], "nocudalib">, Alias<no_offloadlib>;
 def gpulibc : Flag<["-"], "gpulibc">, Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
   HelpText<"Link the LLVM C Library for GPUs">;
 def nogpulibc : Flag<["-"], "nogpulibc">, Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>;

clang/lib/Driver/ToolChains/AMDGPU.cpp

@@ -936,7 +936,8 @@ void ROCMToolChain::addClangTargetOptions(
       DriverArgs.hasArg(options::OPT_nostdlib))
     return;
 
-  if (DriverArgs.hasArg(options::OPT_nogpulib))
+  if (!DriverArgs.hasFlag(options::OPT_offloadlib, options::OPT_no_offloadlib,
+                          true))
     return;
 
   // Get the device name and canonicalize it

clang/lib/Driver/ToolChains/AMDGPUOpenMP.cpp

@@ -49,7 +49,8 @@ void AMDGPUOpenMPToolChain::addClangTargetOptions(
   assert(DeviceOffloadingKind == Action::OFK_OpenMP &&
          "Only OpenMP offloading kinds are supported.");
 
-  if (DriverArgs.hasArg(options::OPT_nogpulib))
+  if (!DriverArgs.hasFlag(options::OPT_offloadlib, options::OPT_no_offloadlib,
+                          true))
     return;
 
   for (auto BCFile : getDeviceLibs(DriverArgs)) {
@@ -141,7 +142,7 @@ AMDGPUOpenMPToolChain::computeMSVCVersion(const Driver *D,
 
 llvm::SmallVector<ToolChain::BitCodeLibraryInfo, 12>
 AMDGPUOpenMPToolChain::getDeviceLibs(const llvm::opt::ArgList &Args) const {
-  if (Args.hasArg(options::OPT_nogpulib))
+  if (!Args.hasFlag(options::OPT_offloadlib, options::OPT_no_offloadlib, true))
     return {};
 
   StringRef GpuArch = getProcessorFromTargetID(

clang/lib/Driver/ToolChains/Clang.cpp

@@ -7117,9 +7117,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
-  // Forward -nogpulib to -cc1.
-  if (Args.hasArg(options::OPT_nogpulib))
-    CmdArgs.push_back("-nogpulib");
+  // Forward --no-offloadlib to -cc1.
+  if (!Args.hasFlag(options::OPT_offloadlib, options::OPT_no_offloadlib, true))
+    CmdArgs.push_back("--no-offloadlib");
 
   if (Arg *A = Args.getLastArg(options::OPT_fcf_protection_EQ)) {
     CmdArgs.push_back(
@@ -9319,7 +9319,8 @@ void LinkerWrapper::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("--save-temps");
 
   // Pass in the C library for GPUs if present and not disabled.
-  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_r, options::OPT_nogpulib,
+  if (Args.hasFlag(options::OPT_offloadlib, OPT_no_offloadlib, true) &&
+      !Args.hasArg(options::OPT_nostdlib, options::OPT_r,
                    options::OPT_nodefaultlibs, options::OPT_nolibc,
                    options::OPT_nogpulibc)) {
     forAllAssociatedToolChains(C, JA, getToolChain(), [&](const ToolChain &TC) {

clang/lib/Driver/ToolChains/CommonArgs.cpp

@@ -1289,7 +1289,8 @@ bool tools::addOpenMPRuntime(const Compilation &C, ArgStringList &CmdArgs,
   if (IsOffloadingHost)
     CmdArgs.push_back("-lomptarget");
 
-  if (IsOffloadingHost && !Args.hasArg(options::OPT_nogpulib))
+  if (IsOffloadingHost &&
+      Args.hasFlag(options::OPT_offloadlib, options::OPT_no_offloadlib, true))
     CmdArgs.push_back("-lomptarget.devicertl");
 
   addArchSpecificRPath(TC, Args, CmdArgs);

clang/lib/Driver/ToolChains/Cuda.cpp

@@ -196,7 +196,8 @@ CudaInstallationDetector::CudaInstallationDetector(
       Candidates.emplace_back(D.SysRoot + "/usr/lib/cuda");
   }
 
-  bool NoCudaLib = Args.hasArg(options::OPT_nogpulib);
+  bool NoCudaLib =
+      !Args.hasFlag(options::OPT_offloadlib, options::OPT_no_offloadlib, true);
 
   for (const auto &Candidate : Candidates) {
     InstallPath = Candidate.Path;
@@ -865,7 +866,8 @@ void CudaToolChain::addClangTargetOptions(
                          options::OPT_fno_cuda_short_ptr, false))
     CC1Args.append({"-mllvm", "--nvptx-short-ptr"});
 
-  if (DriverArgs.hasArg(options::OPT_nogpulib))
+  if (!DriverArgs.hasFlag(options::OPT_offloadlib, options::OPT_no_offloadlib,
+                          true))
     return;
 
   if (DeviceOffloadingKind == Action::OFK_OpenMP &&

clang/lib/Driver/ToolChains/Flang.cpp

@@ -557,7 +557,8 @@ void Flang::addOffloadOptions(Compilation &C, const InputInfoList &Inputs,
       CmdArgs.push_back("-fopenmp-assume-no-thread-state");
     if (Args.hasArg(options::OPT_fopenmp_assume_no_nested_parallelism))
       CmdArgs.push_back("-fopenmp-assume-no-nested-parallelism");
-    if (Args.hasArg(options::OPT_nogpulib))
+    if (!Args.hasFlag(options::OPT_offloadlib, options::OPT_no_offloadlib,
+                      true))
       CmdArgs.push_back("-nogpulib");
   }
 

clang/lib/Driver/ToolChains/HIPAMD.cpp

@@ -352,7 +352,8 @@ VersionTuple HIPAMDToolChain::computeMSVCVersion(const Driver *D,
 llvm::SmallVector<ToolChain::BitCodeLibraryInfo, 12>
 HIPAMDToolChain::getDeviceLibs(const llvm::opt::ArgList &DriverArgs) const {
   llvm::SmallVector<BitCodeLibraryInfo, 12> BCLibs;
-  if (DriverArgs.hasArg(options::OPT_nogpulib) ||
+  if (!DriverArgs.hasFlag(options::OPT_offloadlib, options::OPT_no_offloadlib,
+                          true) ||
       getGPUArch(DriverArgs) == "amdgcnspirv")
     return {};
   ArgStringList LibraryPaths;

clang/lib/Driver/ToolChains/HIPSPV.cpp

@@ -204,7 +204,8 @@ void HIPSPVToolChain::AddHIPIncludeArgs(const ArgList &DriverArgs,
 llvm::SmallVector<ToolChain::BitCodeLibraryInfo, 12>
 HIPSPVToolChain::getDeviceLibs(const llvm::opt::ArgList &DriverArgs) const {
   llvm::SmallVector<ToolChain::BitCodeLibraryInfo, 12> BCLibs;
-  if (DriverArgs.hasArg(options::OPT_nogpulib))
+  if (!DriverArgs.hasFlag(options::OPT_offloadlib, options::OPT_no_offloadlib,
+                          true))
     return {};
 
   ArgStringList LibraryPaths;

clang/lib/Driver/ToolChains/SPIRVOpenMP.cpp

@@ -27,7 +27,8 @@ void SPIRVOpenMPToolChain::addClangTargetOptions(
   if (DeviceOffloadingKind != Action::OFK_OpenMP)
     return;
 
-  if (DriverArgs.hasArg(options::OPT_nogpulib))
+  if (!DriverArgs.hasFlag(options::OPT_offloadlib, options::OPT_no_offloadlib,
+                          true))
     return;
   addOpenMPDeviceRTL(getDriver(), DriverArgs, CC1Args, "", getTriple(), HostTC);
 }