[BOLT] Add icp-inline option

Add an option to only peel ICP targets that can be subsequently inlined.
Yet there's no guarantee that they will be inlined.

The mode is independent from the heuristic used to choose ICP targets: by exec
count, mispredictions, or memory profile.

Reviewed By: rafauler

Differential Revision: https://reviews.llvm.org/D124900

diff --git a/bolt/lib/Passes/IndirectCallPromotion.cpp b/bolt/lib/Passes/IndirectCallPromotion.cpp
index 5775106..33b6904 100644 (file)
--- a/bolt/lib/Passes/IndirectCallPromotion.cpp
+++ b/bolt/lib/Passes/IndirectCallPromotion.cpp
@@ -13,6 +13,7 @@
 #include "bolt/Passes/IndirectCallPromotion.h"
 #include "bolt/Passes/BinaryFunctionCallGraph.h"
 #include "bolt/Passes/DataflowInfoManager.h"
+#include "bolt/Passes/Inliner.h"
 #include "llvm/Support/CommandLine.h"
 
 #define DEBUG_TYPE "ICP"
@@ -120,6 +121,10 @@ static cl::opt<bool> ICPJumpTablesByTarget(
         "for jump tables, optimize indirect jmp targets instead of indices"),
     cl::init(false), cl::ZeroOrMore, cl::Hidden, cl::cat(BoltOptCategory));
 
+static cl::opt<bool> ICPPeelForInline(
+    "icp-inline", cl::desc("only promote call targets eligible for inlining"),
+    cl::init(false), cl::ZeroOrMore, cl::Hidden, cl::cat(BoltOptCategory));
+
 } // namespace opts
 
 namespace llvm {
@@ -1038,6 +1043,20 @@ size_t IndirectCallPromotion::canPromoteCallsite(
     }
   }
 
+  // Filter by inline-ability of target functions, stop at first target that
+  // can't be inlined.
+  if (opts::ICPPeelForInline) {
+    for (size_t I = 0; I < N; ++I) {
+      const MCSymbol *TargetSym = Targets[I].To.Sym;
+      const BinaryFunction *TargetBF = BC.getFunctionForSymbol(TargetSym);
+      if (!BinaryFunctionPass::shouldOptimize(*TargetBF) ||
+          getInliningInfo(*TargetBF).Type == InliningType::INL_NONE) {
+        N = I;
+        break;
+      }
+    }
+  }
+
   // Filter functions that can have ICP applied (for debugging)
   if (!opts::ICPFuncsList.empty()) {
     for (std::string &Name : opts::ICPFuncsList)