1 files changed, 29 insertions, 19 deletions

diff --git a/contrib/llvm-project/llvm/lib/Transforms/IPO/MergeFunctions.cpp b/contrib/llvm-project/llvm/lib/Transforms/IPO/MergeFunctions.cpp
index 97ef872c5499..b850591b4aa6 100644
--- a/contrib/llvm-project/llvm/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/contrib/llvm-project/llvm/lib/Transforms/IPO/MergeFunctions.cpp
@@ -88,12 +88,11 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Transforms/IPO/MergeFunctions.h"
 #include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/IR/Argument.h"
-#include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Constant.h"
 #include "llvm/IR/Constants.h"
@@ -113,7 +112,6 @@
 #include "llvm/IR/User.h"
 #include "llvm/IR/Value.h"
 #include "llvm/IR/ValueHandle.h"
-#include "llvm/IR/ValueMap.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/Casting.h"
@@ -121,8 +119,8 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/IPO.h"
-#include "llvm/Transforms/IPO/MergeFunctions.h"
 #include "llvm/Transforms/Utils/FunctionComparator.h"
+#include "llvm/Transforms/Utils/ModuleUtils.h"
 #include <algorithm>
 #include <cassert>
 #include <iterator>
@@ -139,10 +137,10 @@ STATISTIC(NumThunksWritten, "Number of thunks generated");
 STATISTIC(NumAliasesWritten, "Number of aliases generated");
 STATISTIC(NumDoubleWeak, "Number of new functions created");
 
-static cl::opt<unsigned> NumFunctionsForSanityCheck(
-    "mergefunc-sanity",
-    cl::desc("How many functions in module could be used for "
-             "MergeFunctions pass sanity check. "
+static cl::opt<unsigned> NumFunctionsForVerificationCheck(
+    "mergefunc-verify",
+    cl::desc("How many functions in a module could be used for "
+             "MergeFunctions to pass a basic correctness check. "
              "'0' disables this check. Works only with '-debug' key."),
     cl::init(0), cl::Hidden);
 
@@ -228,10 +226,13 @@ private:
   /// analyzed again.
   std::vector<WeakTrackingVH> Deferred;
 
+  /// Set of values marked as used in llvm.used and llvm.compiler.used.
+  SmallPtrSet<GlobalValue *, 4> Used;
+
 #ifndef NDEBUG
   /// Checks the rules of order relation introduced among functions set.
-  /// Returns true, if sanity check has been passed, and false if failed.
-  bool doSanityCheck(std::vector<WeakTrackingVH> &Worklist);
+  /// Returns true, if check has been passed, and false if failed.
+  bool doFunctionalCheck(std::vector<WeakTrackingVH> &Worklist);
 #endif
 
   /// Insert a ComparableFunction into the FnTree, or merge it away if it's
@@ -330,12 +331,12 @@ PreservedAnalyses MergeFunctionsPass::run(Module &M,
 }
 
 #ifndef NDEBUG
-bool MergeFunctions::doSanityCheck(std::vector<WeakTrackingVH> &Worklist) {
-  if (const unsigned Max = NumFunctionsForSanityCheck) {
+bool MergeFunctions::doFunctionalCheck(std::vector<WeakTrackingVH> &Worklist) {
+  if (const unsigned Max = NumFunctionsForVerificationCheck) {
     unsigned TripleNumber = 0;
     bool Valid = true;
 
-    dbgs() << "MERGEFUNC-SANITY: Started for first " << Max << " functions.\n";
+    dbgs() << "MERGEFUNC-VERIFY: Started for first " << Max << " functions.\n";
 
     unsigned i = 0;
     for (std::vector<WeakTrackingVH>::iterator I = Worklist.begin(),
@@ -351,7 +352,7 @@ bool MergeFunctions::doSanityCheck(std::vector<WeakTrackingVH> &Worklist) {
 
         // If F1 <= F2, then F2 >= F1, otherwise report failure.
         if (Res1 != -Res2) {
-          dbgs() << "MERGEFUNC-SANITY: Non-symmetric; triple: " << TripleNumber
+          dbgs() << "MERGEFUNC-VERIFY: Non-symmetric; triple: " << TripleNumber
                  << "\n";
           dbgs() << *F1 << '\n' << *F2 << '\n';
           Valid = false;
@@ -384,7 +385,7 @@ bool MergeFunctions::doSanityCheck(std::vector<WeakTrackingVH> &Worklist) {
           }
 
           if (!Transitive) {
-            dbgs() << "MERGEFUNC-SANITY: Non-transitive; triple: "
+            dbgs() << "MERGEFUNC-VERIFY: Non-transitive; triple: "
                    << TripleNumber << "\n";
             dbgs() << "Res1, Res3, Res4: " << Res1 << ", " << Res3 << ", "
                    << Res4 << "\n";
@@ -395,7 +396,7 @@ bool MergeFunctions::doSanityCheck(std::vector<WeakTrackingVH> &Worklist) {
       }
     }
 
-    dbgs() << "MERGEFUNC-SANITY: " << (Valid ? "Passed." : "Failed.") << "\n";
+    dbgs() << "MERGEFUNC-VERIFY: " << (Valid ? "Passed." : "Failed.") << "\n";
     return Valid;
   }
   return true;
@@ -410,6 +411,11 @@ static bool isEligibleForMerging(Function &F) {
 bool MergeFunctions::runOnModule(Module &M) {
   bool Changed = false;
 
+  SmallVector<GlobalValue *, 4> UsedV;
+  collectUsedGlobalVariables(M, UsedV, /*CompilerUsed=*/false);
+  collectUsedGlobalVariables(M, UsedV, /*CompilerUsed=*/true);
+  Used.insert(UsedV.begin(), UsedV.end());
+
   // All functions in the module, ordered by hash. Functions with a unique
   // hash value are easily eliminated.
   std::vector<std::pair<FunctionComparator::FunctionHash, Function *>>
@@ -436,7 +442,7 @@ bool MergeFunctions::runOnModule(Module &M) {
     std::vector<WeakTrackingVH> Worklist;
     Deferred.swap(Worklist);
 
-    LLVM_DEBUG(doSanityCheck(Worklist));
+    LLVM_DEBUG(doFunctionalCheck(Worklist));
 
     LLVM_DEBUG(dbgs() << "size of module: " << M.size() << '\n');
     LLVM_DEBUG(dbgs() << "size of worklist: " << Worklist.size() << '\n');
@@ -456,6 +462,7 @@ bool MergeFunctions::runOnModule(Module &M) {
   FnTree.clear();
   FNodesInTree.clear();
   GlobalNumbers.clear();
+  Used.clear();
 
   return Changed;
 }
@@ -484,7 +491,7 @@ static Value *createCast(IRBuilder<> &Builder, Value *V, Type *DestTy) {
   if (SrcTy->isStructTy()) {
     assert(DestTy->isStructTy());
     assert(SrcTy->getStructNumElements() == DestTy->getStructNumElements());
-    Value *Result = UndefValue::get(DestTy);
+    Value *Result = PoisonValue::get(DestTy);
     for (unsigned int I = 0, E = SrcTy->getStructNumElements(); I < E; ++I) {
       Value *Element = createCast(
           Builder, Builder.CreateExtractValue(V, makeArrayRef(I)),
@@ -828,7 +835,10 @@ void MergeFunctions::mergeTwoFunctions(Function *F, Function *G) {
     // For better debugability, under MergeFunctionsPDI, we do not modify G's
     // call sites to point to F even when within the same translation unit.
     if (!G->isInterposable() && !MergeFunctionsPDI) {
-      if (G->hasGlobalUnnamedAddr()) {
+      // Functions referred to by llvm.used/llvm.compiler.used are special:
+      // there are uses of the symbol name that are not visible to LLVM,
+      // usually from inline asm.
+      if (G->hasGlobalUnnamedAddr() && !Used.contains(G)) {
         // G might have been a key in our GlobalNumberState, and it's illegal
         // to replace a key in ValueMap<GlobalValue *> with a non-global.
         GlobalNumbers.erase(G);