[PATCH] D107136: [WIP] [FuncSpec] Handle Available Externally Linkage Function

[Chuanqi Xu via Phabricator via llvm-commits]

ChuanqiXu created this revision.
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ChuanqiXu requested review of this revision.
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This is the successive patch of D105966 <https://reviews.llvm.org/D105966>. With D105544 <https://reviews.llvm.org/D105544>, D105966 <https://reviews.llvm.org/D105966> and this diff, they construct my prototype of ThinLTO for function specialization.

To make this work for 505.mcf_r, it requires that the function specialization handle the case that the argument is already constant, which would be handled by IPSCCP by the design of function specialization. We could discuss it later.


https://reviews.llvm.org/D107136

Files:
  llvm/lib/Transforms/IPO/FunctionSpecialization.cpp


Index: llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
===================================================================
--- llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
+++ llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
@@ -216,6 +216,10 @@
         ValueToValueMapTy EmptyMap;
         Function *Clone = CloneFunction(F, EmptyMap);
         Argument *ClonedArg = Clone->arg_begin() + A.getArgNo();
+        // Functions with AvailableExternallyLinkage would be deleted
+        // in the end.
+        if (Clone->hasAvailableExternallyLinkage())
+          Clone->setLinkage(GlobalValue::InternalLinkage);
 
         // Rewrite calls to the function so that they call the clone instead.
         rewriteCallSites(F, Clone, *ClonedArg, C);
@@ -463,7 +467,8 @@
 
     // Determine if we can track the function's arguments. If so, add the
     // function to the solver's set of argument-tracked functions.
-    if (canTrackArgumentsInterprocedurally(&F)) {
+    if (canTrackArgumentsInterprocedurally(&F) ||
+        F.hasAvailableExternallyLinkage()) {
       LLVM_DEBUG(dbgs() << "FnSpecialization: Can track arguments\n");
       Solver.addArgumentTrackedFunction(&F);
       continue;


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