[llvm] [ctx_prof] Extend `WorkloadImportsManager` to use the contextual profile (PR #98682)

Mircea Trofin via llvm-commits llvm-commits at lists.llvm.org
Fri Jul 12 12:18:57 PDT 2024


https://github.com/mtrofin updated https://github.com/llvm/llvm-project/pull/98682

>From 3ffabdfe77cee4c0769fafb18ed72c5fc5e41c36 Mon Sep 17 00:00:00 2001
From: Mircea Trofin <mtrofin at google.com>
Date: Fri, 12 Jul 2024 12:08:58 -0700
Subject: [PATCH 1/3] [ctx_prof] Extend `WorkloadImportsManager` to use the
 contextual profile

Keeping the json-based input as it's useful for diagnostics or for driving
the import by other means than contextual composition.

The support for the contextual profile is just another modality for
constructing the import list (`WorkloadImportsManager::Workloads`).
Everything else - i.e. the actual importing logic - is already independent
from how that list was obtained.
---
 llvm/lib/Transforms/IPO/FunctionImport.cpp    | 76 +++++++++++++++++--
 .../PGOCtxProfReaderWriterTest.cpp            |  9 +++
 2 files changed, 77 insertions(+), 8 deletions(-)

diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 038785114a0cf..985e419c2bb5e 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -18,6 +18,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Bitcode/BitcodeReader.h"
+#include "llvm/Bitstream/BitstreamWriter.h"
 #include "llvm/IR/AutoUpgrade.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Function.h"
@@ -30,6 +31,7 @@
 #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"
@@ -174,6 +176,10 @@ static cl::opt<std::string> WorkloadDefinitions(
              "}"),
     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;
 }
@@ -586,13 +592,7 @@ 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;
@@ -672,6 +672,66 @@ class WorkloadImportsManager : public ModuleImportsManager {
       });
     }
   }
+
+  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());
+
+    BitstreamCursor Cursor(*Buffer);
+    PGOCtxProfileReader Reader(Cursor);
+    auto Ctx = Reader.loadContexts();
+    if (!Ctx) {
+      report_fatal_error("Failed to parse contextual profiles");
+      return;
+    }
+    const auto &CtxMap = *Ctx;
+    for (const auto &[RootGuid, Root] : CtxMap) {
+      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");
+      DenseSet<GlobalValue::GUID> ContainedGUIDs;
+      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();
+    loadFromJson();
+  }
 };
 
 std::unique_ptr<ModuleImportsManager> ModuleImportsManager::create(
@@ -679,7 +739,7 @@ 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));
diff --git a/llvm/unittests/ProfileData/PGOCtxProfReaderWriterTest.cpp b/llvm/unittests/ProfileData/PGOCtxProfReaderWriterTest.cpp
index d2cdbb28e2fce..6c6798ded00b5 100644
--- a/llvm/unittests/ProfileData/PGOCtxProfReaderWriterTest.cpp
+++ b/llvm/unittests/ProfileData/PGOCtxProfReaderWriterTest.cpp
@@ -115,6 +115,15 @@ TEST_F(PGOCtxProfRWTest, RoundTrip) {
     EXPECT_EQ(Ctxes.size(), 2U);
     for (auto &[G, R] : roots())
       checkSame(*R, Ctxes.find(G)->second);
+
+    DenseSet<GlobalValue::GUID> Guids;
+    Ctxes.at(1U).getContainedGuids(Guids);
+    EXPECT_THAT(Guids,
+                testing::WhenSorted(testing::ElementsAre(1U, 2U, 4U, 5U)));
+
+    Guids.clear();
+    Ctxes.at(3U).getContainedGuids(Guids);
+    EXPECT_THAT(Guids, testing::ElementsAre(3U));
   }
 }
 

>From 8e105503ce6060d51494f07cad37d535e4959522 Mon Sep 17 00:00:00 2001
From: Mircea Trofin <mtrofin at google.com>
Date: Fri, 12 Jul 2024 12:15:38 -0700
Subject: [PATCH 2/3] Removed spurious include of BitstreamWriter, as well as
 (oportunistically) unused one to Constants.

---
 llvm/lib/Transforms/IPO/FunctionImport.cpp | 2 --
 1 file changed, 2 deletions(-)

diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 985e419c2bb5e..9656ff2eaa00a 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -18,9 +18,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Bitcode/BitcodeReader.h"
-#include "llvm/Bitstream/BitstreamWriter.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"

>From b6479f0c4f387e1bf2f46b8f0ab9b3c060571558 Mon Sep 17 00:00:00 2001
From: Mircea Trofin <mtrofin at google.com>
Date: Fri, 12 Jul 2024 12:18:23 -0700
Subject: [PATCH 3/3] reuse the `ContainedGUIDs` container.

---
 llvm/lib/Transforms/IPO/FunctionImport.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 9656ff2eaa00a..28e24e437972e 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -688,7 +688,12 @@ class WorkloadImportsManager : public ModuleImportsManager {
       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
@@ -705,7 +710,6 @@ class WorkloadImportsManager : public ModuleImportsManager {
           RootVI.getSummaryList().front()->modulePath();
       LLVM_DEBUG(dbgs() << "[Workload] Root defining module for " << RootGuid
                         << " is : " << RootDefiningModule << "\n");
-      DenseSet<GlobalValue::GUID> ContainedGUIDs;
       auto &Set = Workloads[RootDefiningModule];
       Root.getContainedGuids(ContainedGUIDs);
       for (auto Guid : ContainedGUIDs)



More information about the llvm-commits mailing list