[ctx_prof] Extend WorkloadImportsManager to use the contextual profile

llvm/lib/Transforms/IPO/FunctionImport.cpp

@@ -19,7 +19,6 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Bitcode/BitcodeReader.h"
 #include "llvm/IR/AutoUpgrade.h"
-#include "llvm/IR/Constants.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/GlobalObject.h"
@@ -30,6 +29,7 @@
 #include "llvm/IR/ModuleSummaryIndex.h"
 #include "llvm/IRReader/IRReader.h"
 #include "llvm/Linker/IRMover.h"
+#include "llvm/ProfileData/PGOCtxProfReader.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
@@ -185,6 +185,10 @@ static cl::opt<bool> ImportAssumeUniqueLocal(
         "user specify the full module path."),
     cl::Hidden);
 
+static cl::opt<std::string>
+    ContextualProfile("thinlto-pgo-ctx-prof",
+                      cl::desc("Path to a contextual profile."), cl::Hidden);
+
 namespace llvm {
 extern cl::opt<bool> EnableMemProfContextDisambiguation;
 }
@@ -604,13 +608,7 @@ class WorkloadImportsManager : public ModuleImportsManager {
     LLVM_DEBUG(dbgs() << "[Workload] Done\n");
   }
 
-public:
-  WorkloadImportsManager(
-      function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
-          IsPrevailing,
-      const ModuleSummaryIndex &Index,
-      DenseMap<StringRef, FunctionImporter::ExportSetTy> *ExportLists)
-      : ModuleImportsManager(IsPrevailing, Index, ExportLists) {
+  void loadFromJson() {
     // Since the workload def uses names, we need a quick lookup
     // name->ValueInfo.
     StringMap<ValueInfo> NameToValueInfo;
@@ -680,15 +678,81 @@ class WorkloadImportsManager : public ModuleImportsManager {
         }
         Set.insert(ElemIt->second);
       }
-      LLVM_DEBUG({
+    }
+  }
+
+  void loadFromCtxProf() {
+    std::error_code EC;
+    auto BufferOrErr = MemoryBuffer::getFileOrSTDIN(ContextualProfile);
+    if (std::error_code EC = BufferOrErr.getError()) {
+      report_fatal_error("Failed to open contextual profile file");
+      return;
+    }
+    auto Buffer = std::move(BufferOrErr.get());
+
+    PGOCtxProfileReader Reader(Buffer->getBuffer());
+    auto Ctx = Reader.loadContexts();
+    if (!Ctx) {
+      report_fatal_error("Failed to parse contextual profiles");
+      return;
+    }
+    const auto &CtxMap = *Ctx;
+    DenseSet<GlobalValue::GUID> ContainedGUIDs;
+    for (const auto &[RootGuid, Root] : CtxMap) {
+      // Avoid ContainedGUIDs to get in/out of scope. Reuse its memory for
+      // subsequent roots, but clear its contents.
+      ContainedGUIDs.clear();
+
+      auto RootVI = Index.getValueInfo(RootGuid);
+      if (!RootVI) {
+        LLVM_DEBUG(dbgs() << "[Workload] Root " << RootGuid
+                          << " not found in this linkage unit.\n");
+        continue;
+      }
+      if (RootVI.getSummaryList().size() != 1) {
+        LLVM_DEBUG(dbgs() << "[Workload] Root " << RootGuid
+                          << " should have exactly one summary, but has "
+                          << RootVI.getSummaryList().size() << ". Skipping.\n");
+        continue;
+      }
+      StringRef RootDefiningModule =
+          RootVI.getSummaryList().front()->modulePath();
+      LLVM_DEBUG(dbgs() << "[Workload] Root defining module for " << RootGuid
+                        << " is : " << RootDefiningModule << "\n");
+      auto &Set = Workloads[RootDefiningModule];
+      Root.getContainedGuids(ContainedGUIDs);
+      for (auto Guid : ContainedGUIDs)
+        if (auto VI = Index.getValueInfo(Guid))
+          Set.insert(VI);
+    }
+  }
+
+public:
+  WorkloadImportsManager(
+      function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
+          IsPrevailing,
+      const ModuleSummaryIndex &Index,
+      DenseMap<StringRef, FunctionImporter::ExportSetTy> *ExportLists)
+      : ModuleImportsManager(IsPrevailing, Index, ExportLists) {
+    if (ContextualProfile.empty() == WorkloadDefinitions.empty()) {
+      report_fatal_error(
+          "Pass only one of: -thinlto-pgo-ctx-prof or -thinlto-workload-def");
+      return;
+    }
+    if (!ContextualProfile.empty())
+      loadFromCtxProf();
+    else
+      loadFromJson();
+    LLVM_DEBUG({
+      for (const auto &[Root, Set] : Workloads) {
         dbgs() << "[Workload] Root: " << Root << " we have " << Set.size()
                << " distinct callees.\n";
         for (const auto &VI : Set) {
           dbgs() << "[Workload] Root: " << Root
                  << " Would include: " << VI.getGUID() << "\n";
         }
-      });
-    }
+      }
+    });
   }
 };
 
@@ -697,7 +761,7 @@ std::unique_ptr<ModuleImportsManager> ModuleImportsManager::create(
         IsPrevailing,
     const ModuleSummaryIndex &Index,
     DenseMap<StringRef, FunctionImporter::ExportSetTy> *ExportLists) {
-  if (WorkloadDefinitions.empty()) {
+  if (WorkloadDefinitions.empty() && ContextualProfile.empty()) {
     LLVM_DEBUG(dbgs() << "[Workload] Using the regular imports manager.\n");
     return std::unique_ptr<ModuleImportsManager>(
         new ModuleImportsManager(IsPrevailing, Index, ExportLists));

llvm/test/ThinLTO/X86/ctxprof.ll

@@ -0,0 +1,72 @@
+; Test workload based importing via -thinlto-pgo-ctx-prof
+; Use external linkage symbols so we don't depend on module paths which are
+; used when computing the GUIDs of internal linkage symbols.
+; The functionality is shared with what workload.ll tests, so here we only care
+; about testing the ctx profile is loaded and handled correctly.
+;
+; Set up
+; RUN: rm -rf %t
+; RUN: mkdir -p %t
+; RUN: split-file %s %t
+;
+; RUN: opt -module-summary %t/m1.ll -o %t/m1.bc
+; RUN: opt -module-summary %t/m2.ll -o %t/m2.bc
+; RUN: llvm-dis %t/m1.bc -o - | FileCheck %s --check-prefix=GUIDS-1
+; RUN: llvm-dis %t/m2.bc -o - | FileCheck %s --check-prefix=GUIDS-2
+;
+; GUIDS-1: name: "m1_f1"
+; GUIDS-1-SAME: guid = 6019442868614718803
+; GUIDS-2: name: "m2_f1"
+; GUIDS-2-SAME: guid = 15593096274670919754
+;
+; RUN: rm -rf %t_baseline
+; RUN: rm -rf %t_exp
+; RUN: mkdir -p %t_baseline
+; RUN: mkdir -p %t_exp
+;
+; Normal run. m1 shouldn't get m2_f1 because it's not referenced from there.
+;
+; RUN: llvm-lto2 run %t/m1.bc %t/m2.bc \
+; RUN:  -o %t_baseline/result.o -save-temps \
+; RUN:  -r %t/m1.bc,m1_f1,plx \
+; RUN:  -r %t/m2.bc,m2_f1,plx
+; RUN: llvm-dis %t_baseline/result.o.1.3.import.bc -o - | FileCheck %s --check-prefix=NOPROF-1
+; RUN: llvm-dis %t_baseline/result.o.2.3.import.bc -o - | FileCheck %s --check-prefix=NOPROF-2
+;
+; NOPROF-1-NOT: m2_f1()
+; NOPROF-2-NOT: m1_f1()
+;
+; The run with workload definitions - same other options.
+;
+; RUN: echo '[ \
+; RUN:        {"Guid": 6019442868614718803, "Counters": [1], "Callsites": [[{"Guid": 15593096274670919754, "Counters": [1]}]]}, \
+; RUN:        {"Guid": 15593096274670919754, "Counters": [1], "Callsites": [[{"Guid": 6019442868614718803, "Counters": [1]}]]} \
+; RUN:  ]' > %t_exp/ctxprof.json
+; RUN: llvm-ctxprof-util fromJSON --input %t_exp/ctxprof.json --output %t_exp/ctxprof.bitstream
+; RUN: llvm-lto2 run %t/m1.bc %t/m2.bc \
+; RUN:  -o %t_exp/result.o -save-temps \
+; RUN:  -thinlto-pgo-ctx-prof=%t_exp/ctxprof.bitstream \
+; RUN:  -r %t/m1.bc,m1_f1,plx \
+; RUN:  -r %t/m2.bc,m2_f1,plx
+; RUN: llvm-dis %t_exp/result.o.1.3.import.bc -o - | FileCheck %s --check-prefix=FIRST
+; RUN: llvm-dis %t_exp/result.o.2.3.import.bc -o - | FileCheck %s --check-prefix=SECOND
+;
+;
+; FIRST: m2_f1()
+; SECOND: m1_f1()
+;
+;--- m1.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-linux-gnu"
+
+define dso_local void @m1_f1() {
+  ret void
+}
+
+;--- m2.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-linux-gnu"
+
+define dso_local void @m2_f1() {
+  ret void
+}