[clang] [clang][Driver][SPIR-V] Allow linking IR using llvm-link (PR #169572)

[Manuel Carrasco via cfe-commits]

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@@ -3637,3 +3637,28 @@ void tools::setComplexRange(const Driver &D, StringRef NewOpt,
   LastOpt = NewOpt;
   Range = NewRange;
 }
+
+void tools::constructLlvmLinkCommand(Compilation &C, const Tool &T,
+                                     const JobAction &JA,
+                                     const InputInfoList &JobInputs,
+                                     const ArgStringList &LinkerInputs,
+                                     const InputInfo &Output,
+                                     const llvm::opt::ArgList &Args,
+                                     const char *OutputFilename) {
+  // Construct llvm-link command.
+  // The output from llvm-link is a bitcode file.
+
+  assert(!LinkerInputs.empty() && !JobInputs.empty() &&
+         "Must have at least one input.");
+
+  ArgStringList LlvmLinkArgs(
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mgcarrasco wrote:

> this function expects that the inputs to llvm-link will be specified by the caller, but the output is handled by this function.

The function optionally handles the output, right? 

https://github.com/llvm/llvm-project/pull/169572