Reformat partially, where I touched for whitespace changes.

[oota-llvm.git] / lib / Transforms / IPO / Inliner.cpp

diff --git a/lib/Transforms/IPO/Inliner.cpp b/lib/Transforms/IPO/Inliner.cpp
index 10b20cfc917f7b2c3281cfad296487f950ddafc4..4ce6dfed7c421ee42940650d5117a1576cd5f5b2 100644 (file)
--- a/lib/Transforms/IPO/Inliner.cpp
+++ b/lib/Transforms/IPO/Inliner.cpp
@@ -16,6 +16,8 @@
 #include "llvm/Transforms/IPO/InlinerPass.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumptionTracker.h"
 #include "llvm/Analysis/CallGraph.h"
 #include "llvm/Analysis/InlineCost.h"
 #include "llvm/IR/CallSite.h"
@@ -74,6 +76,8 @@ Inliner::Inliner(char &ID, int Threshold, bool InsertLifetime)
 /// the call graph.  If the derived class implements this method, it should
 /// always explicitly call the implementation here.
 void Inliner::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<AliasAnalysis>();
+  AU.addRequired<AssumptionTracker>();
   CallGraphSCCPass::getAnalysisUsage(AU);
 }
 
@@ -301,6 +305,13 @@ unsigned Inliner::getInlineThreshold(CallSite CS) const {
   return thres;
 }
 
+static void emitAnalysis(CallSite CS, const Twine &Msg) {
+  Function *Caller = CS.getCaller();
+  LLVMContext &Ctx = Caller->getContext();
+  DebugLoc DLoc = CS.getInstruction()->getDebugLoc();
+  emitOptimizationRemarkAnalysis(Ctx, DEBUG_TYPE, *Caller, DLoc, Msg);
+}
+
 /// shouldInline - Return true if the inliner should attempt to inline
 /// at the given CallSite.
 bool Inliner::shouldInline(CallSite CS) {
@@ -309,12 +320,16 @@ bool Inliner::shouldInline(CallSite CS) {
   if (IC.isAlways()) {
     DEBUG(dbgs() << "    Inlining: cost=always"
           << ", Call: " << *CS.getInstruction() << "\n");
+    emitAnalysis(CS, Twine(CS.getCalledFunction()->getName()) +
+                         " should always be inlined (cost=always)");
     return true;
   }
   
   if (IC.isNever()) {
     DEBUG(dbgs() << "    NOT Inlining: cost=never"
           << ", Call: " << *CS.getInstruction() << "\n");
+    emitAnalysis(CS, Twine(CS.getCalledFunction()->getName() +
+                           " should never be inlined (cost=never)"));
     return false;
   }
   
@@ -323,6 +338,10 @@ bool Inliner::shouldInline(CallSite CS) {
     DEBUG(dbgs() << "    NOT Inlining: cost=" << IC.getCost()
           << ", thres=" << (IC.getCostDelta() + IC.getCost())
           << ", Call: " << *CS.getInstruction() << "\n");
+    emitAnalysis(CS, Twine(CS.getCalledFunction()->getName() +
+                           " too costly to inline (cost=") +
+                         Twine(IC.getCost()) + ", threshold=" +
+                         Twine(IC.getCostDelta() + IC.getCost()) + ")");
     return false;
   }
   
@@ -342,8 +361,7 @@ bool Inliner::shouldInline(CallSite CS) {
   // FIXME: All of this logic should be sunk into getInlineCost. It relies on
   // the internal implementation of the inline cost metrics rather than
   // treating them as truly abstract units etc.
-  if (Caller->hasLocalLinkage() ||
-      Caller->getLinkage() == GlobalValue::LinkOnceODRLinkage) {
+  if (Caller->hasLocalLinkage() || Caller->hasLinkOnceODRLinkage()) {
     int TotalSecondaryCost = 0;
     // The candidate cost to be imposed upon the current function.
     int CandidateCost = IC.getCost() - (InlineConstants::CallPenalty + 1);
@@ -390,6 +408,11 @@ bool Inliner::shouldInline(CallSite CS) {
       DEBUG(dbgs() << "    NOT Inlining: " << *CS.getInstruction() <<
            " Cost = " << IC.getCost() <<
            ", outer Cost = " << TotalSecondaryCost << '\n');
+      emitAnalysis(
+          CS, Twine("Not inlining. Cost of inlining " +
+                    CS.getCalledFunction()->getName() +
+                    " increases the cost of inlining " +
+                    CS.getCaller()->getName() + " in other contexts"));
       return false;
     }
   }
@@ -397,6 +420,10 @@ bool Inliner::shouldInline(CallSite CS) {
   DEBUG(dbgs() << "    Inlining: cost=" << IC.getCost()
         << ", thres=" << (IC.getCostDelta() + IC.getCost())
         << ", Call: " << *CS.getInstruction() << '\n');
+  emitAnalysis(
+      CS, CS.getCalledFunction()->getName() + Twine(" can be inlined into ") +
+              CS.getCaller()->getName() + " with cost=" + Twine(IC.getCost()) +
+              " (threshold=" + Twine(IC.getCostDelta() + IC.getCost()) + ")");
   return true;
 }
 
@@ -416,9 +443,11 @@ static bool InlineHistoryIncludes(Function *F, int InlineHistoryID,
 
 bool Inliner::runOnSCC(CallGraphSCC &SCC) {
   CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
+  AssumptionTracker *AT = &getAnalysis<AssumptionTracker>();
   DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
   const DataLayout *DL = DLP ? &DLP->getDataLayout() : nullptr;
   const TargetLibraryInfo *TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
+  AliasAnalysis *AA = &getAnalysis<AliasAnalysis>();
 
   SmallPtrSet<Function*, 8> SCCFunctions;
   DEBUG(dbgs() << "Inliner visiting SCC:");
@@ -477,7 +506,7 @@ bool Inliner::runOnSCC(CallGraphSCC &SCC) {
 
   
   InlinedArrayAllocasTy InlinedArrayAllocas;
-  InlineFunctionInfo InlineInfo(&CG, DL);
+  InlineFunctionInfo InlineInfo(&CG, DL, AA, AT);
   
   // Now that we have all of the call sites, loop over them and inline them if
   // it looks profitable to do so.
@@ -518,24 +547,35 @@ bool Inliner::runOnSCC(CallGraphSCC &SCC) {
             InlineHistoryIncludes(Callee, InlineHistoryID, InlineHistory))
           continue;
         
-        
-        // If the policy determines that we should inline this function,
-        // try to do so.
-        if (!shouldInline(CS))
-          continue;
+        LLVMContext &CallerCtx = Caller->getContext();
 
         // Get DebugLoc to report. CS will be invalid after Inliner.
         DebugLoc DLoc = CS.getInstruction()->getDebugLoc();
 
+        // If the policy determines that we should inline this function,
+        // try to do so.
+        if (!shouldInline(CS)) {
+          emitOptimizationRemarkMissed(CallerCtx, DEBUG_TYPE, *Caller, DLoc,
+                                       Twine(Callee->getName() +
+                                             " will not be inlined into " +
+                                             Caller->getName()));
+          continue;
+        }
+
         // Attempt to inline the function.
         if (!InlineCallIfPossible(CS, InlineInfo, InlinedArrayAllocas,
-                                  InlineHistoryID, InsertLifetime, DL))
+                                  InlineHistoryID, InsertLifetime, DL)) {
+          emitOptimizationRemarkMissed(CallerCtx, DEBUG_TYPE, *Caller, DLoc,
+                                       Twine(Callee->getName() +
+                                             " will not be inlined into " +
+                                             Caller->getName()));
           continue;
+        }
         ++NumInlined;
 
         // Report the inline decision.
-        Caller->getContext().emitOptimizationRemark(
-            DEBUG_TYPE, *Caller, DLoc,
+        emitOptimizationRemark(
+            CallerCtx, DEBUG_TYPE, *Caller, DLoc,
             Twine(Callee->getName() + " inlined into " + Caller->getName()));
 
         // If inlining this function gave us any new call sites, throw them
@@ -629,6 +669,13 @@ bool Inliner::removeDeadFunctions(CallGraph &CG, bool AlwaysInlineOnly) {
 
     if (!F->isDefTriviallyDead())
       continue;
+
+    // It is unsafe to drop a function with discardable linkage from a COMDAT
+    // without also dropping the other members of the COMDAT.
+    // The inliner doesn't visit non-function entities which are in COMDAT
+    // groups so it is unsafe to do so *unless* the linkage is local.
+    if (!F->hasLocalLinkage() && F->hasComdat())
+      continue;
     
     // Remove any call graph edges from the function to its callees.
     CGN->removeAllCalledFunctions();