[ThinLTO] Add importing stats to thin link

Summary:
Previously we could only get the number of imported functions and
variables from the backend. This adds stats to the thin link where the
importing is decided.

Reviewers: wmi

Subscribers: inglorion, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D53337

llvm-svn: 344658

1 files changed, 27 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 366ac2b95f4..16a3d112b29 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -60,8 +60,17 @@ using namespace llvm;
 
 #define DEBUG_TYPE "function-import"
 
-STATISTIC(NumImportedFunctions, "Number of functions imported");
-STATISTIC(NumImportedGlobalVars, "Number of global variables imported");
+STATISTIC(NumImportedFunctionsThinLink,
+          "Number of functions thin link decided to import");
+STATISTIC(NumImportedHotFunctionsThinLink,
+          "Number of hot functions thin link decided to import");
+STATISTIC(NumImportedCriticalFunctionsThinLink,
+          "Number of critical functions thin link decided to import");
+STATISTIC(NumImportedGlobalVarsThinLink,
+          "Number of global variables thin link decided to import");
+STATISTIC(NumImportedFunctions, "Number of functions imported in backend");
+STATISTIC(NumImportedGlobalVars,
+          "Number of global variables imported in backend");
 STATISTIC(NumImportedModules, "Number of modules imported from");
 STATISTIC(NumDeadSymbols, "Number of dead stripped symbols in index");
 STATISTIC(NumLiveSymbols, "Number of live symbols in index");
@@ -281,7 +290,10 @@ static void computeImportForReferencedGlobals(
           !RefSummary->notEligibleToImport() &&
           !GlobalValue::isInterposableLinkage(RefSummary->linkage()) &&
           RefSummary->refs().empty()) {
-        ImportList[RefSummary->modulePath()].insert(VI.getGUID());
+        auto ILI = ImportList[RefSummary->modulePath()].insert(VI.getGUID());
+        // Only update stat if we haven't already imported this variable.
+        if (ILI.second)
+          NumImportedGlobalVarsThinLink++;
         if (ExportLists)
           (*ExportLists)[RefSummary->modulePath()].insert(VI.getGUID());
         break;
@@ -363,6 +375,11 @@ static void computeImportForFunction(
     auto &CalleeSummary = std::get<1>(IT.first->second);
     auto &FailureInfo = std::get<2>(IT.first->second);
 
+    bool IsHotCallsite =
+        Edge.second.getHotness() == CalleeInfo::HotnessType::Hot;
+    bool IsCriticalCallsite =
+        Edge.second.getHotness() == CalleeInfo::HotnessType::Critical;
+
     const FunctionSummary *ResolvedCalleeSummary = nullptr;
     if (CalleeSummary) {
       assert(PreviouslyVisited);
@@ -434,6 +451,13 @@ static void computeImportForFunction(
       // We previously decided to import this GUID definition if it was already
       // inserted in the set of imports from the exporting module.
       bool PreviouslyImported = !ILI.second;
+      if (!PreviouslyImported) {
+        NumImportedFunctionsThinLink++;
+        if (IsHotCallsite)
+          NumImportedHotFunctionsThinLink++;
+        if (IsCriticalCallsite)
+          NumImportedCriticalFunctionsThinLink++;
+      }
 
       // Make exports in the source module.
       if (ExportLists) {
@@ -467,8 +491,6 @@ static void computeImportForFunction(
       return Threshold * ImportInstrFactor;
     };
 
-    bool IsHotCallsite =
-        Edge.second.getHotness() == CalleeInfo::HotnessType::Hot;
     const auto AdjThreshold = GetAdjustedThreshold(Threshold, IsHotCallsite);
 
     ImportCount++;