[ThinLTO] Print names in function import debug messages when available

Summary:
Rather than just print the GUID, when it is available in the index,
print the global name as well in the function import thin link debug
messages. Names will be available when the combined index is being
built by the same process, e.g. a linker or "llvm-lto2 run".

Reviewers: davidxl

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, llvm-commits

Differential Revision: https://reviews.llvm.org/D48612

llvm-svn: 335760

llvm/include/llvm/IR/ModuleSummaryIndex.h

@@ -181,6 +181,13 @@ struct ValueInfo {
   bool isDSOLocal() const;
 };
 
+inline raw_ostream &operator<<(raw_ostream &OS, const ValueInfo &VI) {
+  OS << VI.getGUID();
+  if (!VI.name().empty())
+    OS << " (" << VI.name() << ")";
+  return OS;
+}
+
 inline bool operator==(const ValueInfo &A, const ValueInfo &B) {
   assert(A.getRef() && B.getRef() &&
          "Need ValueInfo with non-null Ref for comparison");

llvm/lib/Transforms/IPO/FunctionImport.cpp

@@ -254,7 +254,7 @@ static void computeImportForReferencedGlobals(
       continue;
     }
 
-    LLVM_DEBUG(dbgs() << " ref -> " << VI.getGUID() << "\n");
+    LLVM_DEBUG(dbgs() << " ref -> " << VI << "\n");
 
     for (auto &RefSummary : VI.getSummaryList())
       if (RefSummary->getSummaryKind() == GlobalValueSummary::GlobalVarKind &&
@@ -284,8 +284,8 @@ static void computeImportForFunction(
   static int ImportCount = 0;
   for (auto &Edge : Summary.calls()) {
     ValueInfo VI = Edge.first;
-    LLVM_DEBUG(dbgs() << " edge -> " << VI.getGUID()
-                      << " Threshold:" << Threshold << "\n");
+    LLVM_DEBUG(dbgs() << " edge -> " << VI << " Threshold:" << Threshold
+                      << "\n");
 
     if (ImportCutoff >= 0 && ImportCount >= ImportCutoff) {
       LLVM_DEBUG(dbgs() << "ignored! import-cutoff value of " << ImportCutoff
@@ -399,8 +399,13 @@ static void ComputeImportForModule(
   // Populate the worklist with the import for the functions in the current
   // module
   for (auto &GVSummary : DefinedGVSummaries) {
+#ifndef NDEBUG
+    // FIXME: Change the GVSummaryMapTy to hold ValueInfo instead of GUID
+    // so this map look up (and possibly others) can be avoided.
+    auto VI = Index.getValueInfo(GVSummary.first);
+#endif
     if (!Index.isGlobalValueLive(GVSummary.second)) {
-      LLVM_DEBUG(dbgs() << "Ignores Dead GUID: " << GVSummary.first << "\n");
+      LLVM_DEBUG(dbgs() << "Ignores Dead GUID: " << VI << "\n");
       continue;
     }
     auto *FuncSummary =
@@ -408,7 +413,7 @@ static void ComputeImportForModule(
     if (!FuncSummary)
       // Skip import for global variables
       continue;
-    LLVM_DEBUG(dbgs() << "Initialize import for " << GVSummary.first << "\n");
+    LLVM_DEBUG(dbgs() << "Initialize import for " << VI << "\n");
     computeImportForFunction(*FuncSummary, Index, ImportInstrLimit,
                              DefinedGVSummaries, Worklist, ImportList,
                              ExportLists);
@@ -600,14 +605,16 @@ void llvm::computeDeadSymbols(
   }
 
   // Add values flagged in the index as live roots to the worklist.
-  for (const auto &Entry : Index)
+  for (const auto &Entry : Index) {
+    auto VI = Index.getValueInfo(Entry);
     for (auto &S : Entry.second.SummaryList)
       if (S->isLive()) {
-        LLVM_DEBUG(dbgs() << "Live root: " << Entry.first << "\n");
-        Worklist.push_back(ValueInfo(/*IsAnalysis=*/false, &Entry));
+        LLVM_DEBUG(dbgs() << "Live root: " << VI << "\n");
+        Worklist.push_back(VI);
         ++LiveSymbols;
         break;
       }
+  }
 
   // Make value live and add it to the worklist if it was not live before.
   auto visit = [&](ValueInfo VI) {

llvm/test/ThinLTO/X86/Inputs/funcimport-debug.ll

@@ -0,0 +1,10 @@
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+
+define void @foo() #0 {
+entry:
+  ret void
+}
+
+@baz = constant i32 10, align 4

llvm/test/ThinLTO/X86/deadstrip.ll

@@ -1,3 +1,6 @@
+; Require asserts for -debug-only
+; REQUIRES: asserts
+
 ; RUN: opt -module-summary %s -o %t1.bc
 ; RUN: opt -module-summary %p/Inputs/deadstrip.ll -o %t2.bc
 ; RUN: llvm-lto -thinlto-action=thinlink -o %t.index.bc %t1.bc %t2.bc
@@ -18,7 +21,9 @@
 ; RUN:   -r %t2.bc,_baz,pl \
 ; RUN:   -r %t2.bc,_boo,pl \
 ; RUN:   -r %t2.bc,_dead_func,l \
-; RUN:   -r %t2.bc,_another_dead_func,pl
+; RUN:   -r %t2.bc,_another_dead_func,pl \
+; RUN:   -thinlto-threads=1 \
+; RUN:	 -debug-only=function-import 2>&1 | FileCheck %s --check-prefix=DEBUG
 ; RUN: llvm-dis < %t.out.1.3.import.bc | FileCheck %s --check-prefix=LTO2
 ; RUN: llvm-dis < %t.out.2.3.import.bc | FileCheck %s --check-prefix=LTO2-CHECK2
 ; RUN: llvm-nm %t.out.1 | FileCheck %s --check-prefix=CHECK2-NM
@@ -71,6 +76,13 @@
 ; CHECK-NM-NOT: bar
 ; CHECK-NM-NOT: dead
 
+; DEBUG: Live root: 2412314959268824392 (llvm.global_ctors)
+; DEBUG: Live root: 15822663052811949562 (main)
+; DEBUG: Ignores Dead GUID: 7342339837106705152 (dead_func)
+; DEBUG: Ignores Dead GUID: 7546896869197086323 (baz)
+; DEBUG: Initialize import for 15611644523426561710 (boo)
+; DEBUG: Ignores Dead GUID: 2384416018110111308 (another_dead_func)
+
 ; Next test the case where Inputs/deadstrip.ll does not get a module index,
 ; which will cause it to be handled by regular LTO in the new LTO API.
 ; In that case there are uses of @dead_func in the regular LTO partition

llvm/test/ThinLTO/X86/funcimport-debug.ll

@@ -0,0 +1,35 @@
+; Test of function importing debug messages
+
+; Require asserts for -debug-only
+; REQUIRES: asserts
+
+; Do setup work for all below tests: generate bitcode and combined index
+; RUN: opt -module-summary %s -o %t1.bc
+; RUN: opt -module-summary %p/Inputs/funcimport-debug.ll -o %t2.bc
+
+; RUN: llvm-lto2 run %t1.bc %t2.bc -o %t.o -save-temps \
+; RUN:     -r=%t1.bc,_main,plx \
+; RUN:     -r=%t1.bc,_foo,l \
+; RUN:     -r=%t1.bc,_baz,l \
+; RUN:     -r=%t2.bc,_foo,plx \
+; RUN:     -r=%t2.bc,_baz,plx \
+; RUN:     -thinlto-threads=1 \
+; RUN:     -debug-only=function-import 2>&1 | FileCheck %s
+
+; CHECK-DAG: Initialize import for 6699318081062747564 (foo)
+; CHECK-DAG: Initialize import for 15822663052811949562 (main)
+; CHECK-DAG: ref -> 7546896869197086323 (baz)
+; CHECK-DAG: edge -> 6699318081062747564 (foo) Threshold:100
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+define i32 @main() #0 {
+entry:
+  call void (...) @foo()
+  %0 = load i32, i32* @baz, align 4
+  ret i32 %0
+}
+
+declare void @foo(...) #1
+@baz = external global i32