[Clang] add option --offload-jobs=N (#135229)

for specifying number of threads for clang-linker-wrapper.

Author: yxsamliu

clang/include/clang/Driver/Options.td

@@ -1234,6 +1234,10 @@ def offload_compression_level_EQ : Joined<["--"], "offload-compression-level=">,
   Flags<[HelpHidden]>,
   HelpText<"Compression level for offload device binaries (HIP only)">;
 
+def offload_jobs_EQ : Joined<["--"], "offload-jobs=">,
+  HelpText<"Specify the number of threads to use for device offloading tasks"
+           " during compilation.">;
+
 defm offload_via_llvm : BoolFOption<"offload-via-llvm",
   LangOpts<"OffloadViaLLVM">, DefaultFalse,
   PosFlag<SetTrue, [], [ClangOption, CC1Option], "Use">,

clang/lib/Driver/ToolChains/Clang.cpp

@@ -1031,6 +1031,7 @@ void Clang::AddPreprocessingOptions(Compilation &C, const JobAction &JA,
     if (JA.isOffloading(Action::OFK_HIP)) {
       Args.ClaimAllArgs(options::OPT_offload_compress);
       Args.ClaimAllArgs(options::OPT_no_offload_compress);
+      Args.ClaimAllArgs(options::OPT_offload_jobs_EQ);
     }
 
     bool HasTarget = false;
@@ -9361,6 +9362,18 @@ void LinkerWrapper::ConstructJob(Compilation &C, const JobAction &JA,
       CmdArgs.push_back(LinkArg);
 
   addOffloadCompressArgs(Args, CmdArgs);
+
+  if (Arg *A = Args.getLastArg(options::OPT_offload_jobs_EQ)) {
+    int NumThreads;
+    if (StringRef(A->getValue()).getAsInteger(10, NumThreads) ||
+        NumThreads <= 0)
+      C.getDriver().Diag(diag::err_drv_invalid_int_value)
+          << A->getAsString(Args) << A->getValue();
+    else
+      CmdArgs.push_back(
+          Args.MakeArgString("--wrapper-jobs=" + Twine(NumThreads)));
+  }
+
   const char *Exec =
       Args.MakeArgString(getToolChain().GetProgramPath("clang-linker-wrapper"));
 

clang/test/Driver/hip-options.hip

@@ -243,6 +243,19 @@
 // NO-WARN-ATOMIC-NOT: clang{{.*}} "-triple" "x86_64-unknown-linux-gnu" {{.*}} "-Werror=atomic-alignment"
 // NO-WARN-ATOMIC-NOT: clang{{.*}} "-triple" "x86_64-unknown-linux-gnu" {{.*}} "-Wno-error=atomic-alignment"
 
-// Check --offload-compress does not cause warning.
+// Check --offload-compress --offload-jobs=N does not cause warning.
 // RUN: %clang -### -Werror --target=x86_64-unknown-linux-gnu -nogpuinc -nogpulib \
-// RUN:   --offload-arch=gfx1100 --offload-compress --offload-host-only -M %s
+// RUN:   --offload-arch=gfx1100 --offload-compress --offload-host-only -M %s \
+// RUN:   --offload-jobs=4
+
+// Check --offload-jobs=N option.
+
+// RUN: %clang -### -Werror --target=x86_64-unknown-linux-gnu -nogpuinc -nogpulib \
+// RUN:   --offload-arch=gfx1100 --offload-new-driver --offload-jobs=4 %s 2>&1 | \
+// RUN:   FileCheck -check-prefix=JOBS %s
+// JOBS: clang-linker-wrapper{{.*}} "--wrapper-jobs=4"
+
+// RUN: not %clang -### --target=x86_64-unknown-linux-gnu -nogpuinc -nogpulib \
+// RUN:   --offload-arch=gfx1100 --offload-new-driver --offload-jobs=0x4 %s 2>&1 | \
+// RUN:   FileCheck -check-prefix=INVJOBS %s
+// INVJOBS: clang: error: invalid integral value '0x4' in '--offload-jobs=0x4'