Add MaxChainSize to CDSortConfig

Author: MaskRay

llvm/include/llvm/Transforms/Utils/CodeLayout.h

@@ -65,6 +65,8 @@ struct CDSortConfig {
   unsigned CacheEntries = 16;
   /// The size of a line in the cache.
   unsigned CacheSize = 2048;
+  /// The maximum size of a chain to create.
+  unsigned MaxChainSize = 128;
   /// The power exponent for the distance-based locality.
   double DistancePower = 0.25;
   /// The scale factor for the frequency-based locality.

llvm/lib/Transforms/Utils/CodeLayout.cpp

@@ -62,12 +62,6 @@ cl::opt<bool> ApplyExtTspWithoutProfile(
     "ext-tsp-apply-without-profile",
     cl::desc("Whether to apply ext-tsp placement for instances w/o profile"),
     cl::init(true), cl::Hidden);
-
-namespace codelayout {
-cl::opt<unsigned>
-    CDMaxChainSize("cdsort-max-chain-size", cl::Hidden, cl::init(128),
-                   cl::desc("The maximum size of a chain to create"));
-}
 } // namespace llvm
 
 // Algorithm-specific params for Ext-TSP. The values are tuned for the best
@@ -129,6 +123,10 @@ static cl::opt<unsigned> CacheEntries("cds-cache-entries", cl::ReallyHidden,
 static cl::opt<unsigned> CacheSize("cds-cache-size", cl::ReallyHidden,
                                    cl::desc("The size of a line in the cache"));
 
+static cl::opt<unsigned>
+    CDMaxChainSize("cdsort-max-chain-size", cl::ReallyHidden,
+                   cl::desc("The maximum size of a chain to create"));
+
 static cl::opt<double> DistancePower(
     "cds-distance-power", cl::ReallyHidden,
     cl::desc("The power exponent for the distance-based locality"));
@@ -1163,7 +1161,7 @@ class CDSortImpl {
         if (Edge->isSelfEdge())
           continue;
         if (Edge->srcChain()->numBlocks() + Edge->dstChain()->numBlocks() >
-            CDMaxChainSize)
+            Config.MaxChainSize)
           continue;
 
         // Compute the gain of merging the two chains.
@@ -1461,6 +1459,8 @@ std::vector<uint64_t> codelayout::computeCacheDirectedLayout(
     Config.CacheEntries = CacheEntries;
   if (CacheSize.getNumOccurrences() > 0)
     Config.CacheSize = CacheSize;
+  if (CDMaxChainSize.getNumOccurrences() > 0)
+    Config.MaxChainSize = CDMaxChainSize;
   if (DistancePower.getNumOccurrences() > 0)
     Config.DistancePower = DistancePower;
   if (FrequencyScale.getNumOccurrences() > 0)

llvm/unittests/Transforms/Utils/CodeLayoutTest.cpp

@@ -1,5 +1,4 @@
 #include "llvm/Transforms/Utils/CodeLayout.h"
-#include "llvm/Support/CommandLine.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include <vector>
@@ -8,10 +7,6 @@ using namespace llvm;
 using namespace llvm::codelayout;
 using testing::ElementsAreArray;
 
-namespace llvm::codelayout {
-extern cl::opt<unsigned> CDMaxChainSize;
-}
-
 namespace {
 TEST(CodeLayout, ThreeFunctions) {
   // Place the most likely successor (2) first.
@@ -48,11 +43,11 @@ TEST(CodeLayout, HotChain) {
 
     // -cdsort-max-chain-size disables forming a larger chain and therefore may
     // change the result.
-    unsigned Saved = CDMaxChainSize;
-    CDMaxChainSize.setValue(3);
-    Order = computeCacheDirectedLayout(Sizes, Counts, Edges, CallOffsets);
+    CDSortConfig Config;
+    Config.MaxChainSize = 3;
+    Order =
+        computeCacheDirectedLayout(Config, Sizes, Counts, Edges, CallOffsets);
     EXPECT_THAT(Order, ElementsAreArray({0, 3, 4, 1, 2}));
-    CDMaxChainSize.setValue(Saved);
   }
 }