[llvm-branch-commits] [llvm] [Analysis] Add DebugInfoCache analysis (PR #118629)

Wed Dec 4 05:17:37 PST 2024

llvmbot wrote:




@llvm/pr-subscribers-llvm-ir

Author: Artem Pianykh (artempyanykh)

<details>
<summary>Changes</summary>

Stacked PRs:
 * #118630
 * __->__#118629
 * #118628
 * #118627
 * #118626
 * #118625
 * #118624
 * #118623
 * #118622
 * #118621
 * #118620


--- --- ---

### [Analysis] Add DebugInfoCache analysis


Summary:
The analysis simply primes and caches DebugInfoFinders for each DICompileUnit in a module. This
allows (future) callers like CoroSplitPass to compute global debug info metadata (required for
coroutine function cloning) much faster. Specifically, pay the price of DICompileUnit processing
only once per compile unit, rather than once per coroutine.

Test Plan:
Added a smoke test for the new analysis
ninja check-llvm-unit check-llvm

---
Full diff: https://github.com/llvm/llvm-project/pull/118629.diff


8 Files Affected:

- (added) llvm/include/llvm/Analysis/DebugInfoCache.h (+50) 
- (modified) llvm/include/llvm/IR/DebugInfo.h (+3-1) 
- (modified) llvm/lib/Analysis/CMakeLists.txt (+1) 
- (added) llvm/lib/Analysis/DebugInfoCache.cpp (+47) 
- (modified) llvm/lib/Passes/PassBuilder.cpp (+1) 
- (modified) llvm/lib/Passes/PassRegistry.def (+1) 
- (modified) llvm/unittests/Analysis/CMakeLists.txt (+1) 
- (added) llvm/unittests/Analysis/DebugInfoCacheTest.cpp (+211) 


``````````diff

diff --git a/llvm/include/llvm/Analysis/DebugInfoCache.h b/llvm/include/llvm/Analysis/DebugInfoCache.h
new file mode 100644
index 00000000000000..dbd6802c99ea01
--- /dev/null
+++ b/llvm/include/llvm/Analysis/DebugInfoCache.h
@@ -0,0 +1,50 @@
+//===- llvm/Analysis/DebugInfoCache.h - debug info cache --------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains an analysis that builds a cache of debug info for each
+// DICompileUnit in a module.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_DEBUGINFOCACHE_H
+#define LLVM_ANALYSIS_DEBUGINFOCACHE_H
+
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+/// Processes and caches debug info for each DICompileUnit in a module.
+///
+/// The result of the analysis is a set of DebugInfoFinders primed on their
+/// respective DICompileUnit. Such DebugInfoFinders can be used to speed up
+/// function cloning which otherwise requires an expensive traversal of
+/// DICompileUnit-level debug info. See an example usage in CoroSplit.
+class DebugInfoCache {
+public:
+  using DIFinderCache = SmallDenseMap<const DICompileUnit *, DebugInfoFinder>;
+  DIFinderCache Result;
+
+  DebugInfoCache(const Module &M);
+
+  bool invalidate(Module &, const PreservedAnalyses &,
+                  ModuleAnalysisManager::Invalidator &);
+};
+
+class DebugInfoCacheAnalysis
+    : public AnalysisInfoMixin<DebugInfoCacheAnalysis> {
+  friend AnalysisInfoMixin<DebugInfoCacheAnalysis>;
+  static AnalysisKey Key;
+
+public:
+  using Result = DebugInfoCache;
+  Result run(Module &M, ModuleAnalysisManager &);
+};
+} // namespace llvm
+
+#endif
diff --git a/llvm/include/llvm/IR/DebugInfo.h b/llvm/include/llvm/IR/DebugInfo.h
index 73f45c3769be44..11907fbb7f20b3 100644
--- a/llvm/include/llvm/IR/DebugInfo.h
+++ b/llvm/include/llvm/IR/DebugInfo.h
@@ -120,11 +120,13 @@ class DebugInfoFinder {
   /// Process subprogram.
   void processSubprogram(DISubprogram *SP);
 
+  /// Process a compile unit.
+  void processCompileUnit(DICompileUnit *CU);
+
   /// Clear all lists.
   void reset();
 
 private:
-  void processCompileUnit(DICompileUnit *CU);
   void processScope(DIScope *Scope);
   void processType(DIType *DT);
   bool addCompileUnit(DICompileUnit *CU);
diff --git a/llvm/lib/Analysis/CMakeLists.txt b/llvm/lib/Analysis/CMakeLists.txt
index 0db5b80f336cb5..db9a569e301563 100644
--- a/llvm/lib/Analysis/CMakeLists.txt
+++ b/llvm/lib/Analysis/CMakeLists.txt
@@ -52,6 +52,7 @@ add_llvm_component_library(LLVMAnalysis
   DDGPrinter.cpp
   ConstraintSystem.cpp
   Delinearization.cpp
+  DebugInfoCache.cpp
   DemandedBits.cpp
   DependenceAnalysis.cpp
   DependenceGraphBuilder.cpp
diff --git a/llvm/lib/Analysis/DebugInfoCache.cpp b/llvm/lib/Analysis/DebugInfoCache.cpp
new file mode 100644
index 00000000000000..c1a3e89f0a6ccf
--- /dev/null
+++ b/llvm/lib/Analysis/DebugInfoCache.cpp
@@ -0,0 +1,47 @@
+//===- llvm/Analysis/DebugInfoCache.cpp - debug info cache ----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains an analysis that builds a cache of debug info for each
+// DICompileUnit in a module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/DebugInfoCache.h"
+#include "llvm/IR/Module.h"
+
+using namespace llvm;
+
+namespace {
+DebugInfoFinder processCompileUnit(DICompileUnit *CU) {
+  DebugInfoFinder DIFinder;
+  DIFinder.processCompileUnit(CU);
+
+  return DIFinder;
+}
+} // namespace
+
+DebugInfoCache::DebugInfoCache(const Module &M) {
+  for (const auto CU : M.debug_compile_units()) {
+    auto DIFinder = processCompileUnit(CU);
+    Result[CU] = std::move(DIFinder);
+  }
+}
+
+bool DebugInfoCache::invalidate(Module &M, const PreservedAnalyses &PA,
+                                ModuleAnalysisManager::Invalidator &) {
+  // Check whether the analysis has been explicitly invalidated. Otherwise, it's
+  // stateless and remains preserved.
+  auto PAC = PA.getChecker<DebugInfoCacheAnalysis>();
+  return !PAC.preservedWhenStateless();
+}
+
+AnalysisKey DebugInfoCacheAnalysis::Key;
+
+DebugInfoCache DebugInfoCacheAnalysis::run(Module &M, ModuleAnalysisManager &) {
+  return DebugInfoCache(M);
+}
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index ba52a37df9c25d..a900be130bdeb5 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -34,6 +34,7 @@
 #include "llvm/Analysis/DDGPrinter.h"
 #include "llvm/Analysis/DXILMetadataAnalysis.h"
 #include "llvm/Analysis/DXILResource.h"
+#include "llvm/Analysis/DebugInfoCache.h"
 #include "llvm/Analysis/Delinearization.h"
 #include "llvm/Analysis/DemandedBits.h"
 #include "llvm/Analysis/DependenceAnalysis.h"
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index 7c3798f6462a46..d697c7c8ab83b8 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -21,6 +21,7 @@
 MODULE_ANALYSIS("callgraph", CallGraphAnalysis())
 MODULE_ANALYSIS("collector-metadata", CollectorMetadataAnalysis())
 MODULE_ANALYSIS("ctx-prof-analysis", CtxProfAnalysis())
+MODULE_ANALYSIS("debug-info-cache", DebugInfoCacheAnalysis())
 MODULE_ANALYSIS("dxil-metadata", DXILMetadataAnalysis())
 MODULE_ANALYSIS("dxil-resource", DXILResourceAnalysis())
 MODULE_ANALYSIS("inline-advisor", InlineAdvisorAnalysis())
diff --git a/llvm/unittests/Analysis/CMakeLists.txt b/llvm/unittests/Analysis/CMakeLists.txt
index 76d16513d93417..73694a1d6ba297 100644
--- a/llvm/unittests/Analysis/CMakeLists.txt
+++ b/llvm/unittests/Analysis/CMakeLists.txt
@@ -25,6 +25,7 @@ set(ANALYSIS_TEST_SOURCES
   ConstraintSystemTest.cpp
   CtxProfAnalysisTest.cpp
   DDGTest.cpp
+  DebugInfoCacheTest.cpp
   DomTreeUpdaterTest.cpp
   DXILResourceTest.cpp
   GraphWriterTest.cpp
diff --git a/llvm/unittests/Analysis/DebugInfoCacheTest.cpp b/llvm/unittests/Analysis/DebugInfoCacheTest.cpp
new file mode 100644
index 00000000000000..b32e4cb543158a
--- /dev/null
+++ b/llvm/unittests/Analysis/DebugInfoCacheTest.cpp
@@ -0,0 +1,211 @@
+//===- DebugInfoCacheTest.cpp - DebugInfoCache unit tests -----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/DebugInfoCache.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/raw_ostream.h"
+#include "gtest/gtest.h"
+
+namespace llvm {
+namespace {
+
+// Forward declare the assembly
+extern StringRef MultiCUModule;
+
+const DICompileUnit *findCU(const Module &M, StringRef FileName) {
+  for (const auto CU : M.debug_compile_units()) {
+    if (CU->getFilename() == FileName)
+      return CU;
+  }
+
+  return nullptr;
+}
+
+class DebugInfoCacheTest : public testing::Test {
+protected:
+  LLVMContext C;
+
+  std::unique_ptr<Module> makeModule(StringRef Assembly) {
+    SMDiagnostic Err;
+    auto M = parseAssemblyString(Assembly, Err, C);
+    if (!M)
+      Err.print("DebugInfoCacheTest", errs());
+
+    verifyModule(*M, &errs());
+    return M;
+  }
+};
+
+TEST_F(DebugInfoCacheTest, TestEmpty) {
+  auto M = makeModule("");
+  DebugInfoCache DIC{*M};
+  EXPECT_EQ(DIC.Result.size(), 0u);
+}
+
+TEST_F(DebugInfoCacheTest, TestMultiCU) {
+  auto M = makeModule(MultiCUModule);
+  DebugInfoCache DIC{*M};
+  EXPECT_EQ(DIC.Result.size(), 2u);
+
+  auto *File1CU = findCU(*M, "file1.cpp");
+  EXPECT_NE(File1CU, nullptr);
+
+  auto File1DIFinder = DIC.Result.find(File1CU);
+  EXPECT_NE(File1DIFinder, DIC.Result.end());
+
+  EXPECT_EQ(File1DIFinder->getSecond().compile_unit_count(), 1u);
+  EXPECT_EQ(File1DIFinder->getSecond().type_count(), 6u);
+  EXPECT_EQ(File1DIFinder->getSecond().subprogram_count(), 0u);
+  EXPECT_EQ(File1DIFinder->getSecond().scope_count(), 1u);
+
+  auto *File2CU = findCU(*M, "file2.cpp");
+  EXPECT_NE(File1CU, nullptr);
+
+  auto File2DIFinder = DIC.Result.find(File2CU);
+  EXPECT_NE(File2DIFinder, DIC.Result.end());
+
+  EXPECT_EQ(File2DIFinder->getSecond().compile_unit_count(), 1u);
+  EXPECT_EQ(File2DIFinder->getSecond().type_count(), 2u);
+  EXPECT_EQ(File2DIFinder->getSecond().subprogram_count(), 0u);
+  EXPECT_EQ(File2DIFinder->getSecond().scope_count(), 2u);
+}
+
+/* Generated roughly by
+file1.cpp:
+struct file1_extern_type1;
+struct file1_extern_type2;
+
+namespace file1 {
+typedef struct file1_type1 { int x; float y; } file1_type1;
+file1_type1 global{0, 1.};
+} // file1
+
+extern struct file1_extern_type1 *file1_extern_func1(struct
+file1_extern_type2*);
+
+file1::file1_type1 file1_func1(file1::file1_type1 x) { return x; }
+--------
+file2.cpp:
+struct file2_extern_type1;
+struct file2_extern_type2;
+
+namespace file2 {
+typedef struct file2_type1 { float x; float y; } file2_type1;
+enum class file2_type2 { opt1, opt2 };
+
+namespace inner {
+file2_type2 inner_global{file2_type2::opt2};
+} // inner
+} // file2
+
+extern struct file2_extern_type1 *file2_extern_func1(struct
+file2_extern_type2*);
+
+file2::file2_type1 file2_func1(file2::file2_type1 x, file2::file2_type2 y) {
+return x; }
+--------
+$ clang -S -emit-llvm file*.cpp
+$ llvm-link -S -o single.ll file*.ll
+*/
+StringRef MultiCUModule = R"""(
+%"struct.file1::file1_type1" = type { i32, float }
+%"struct.file2::file2_type1" = type { float, float }
+
+ at _ZN5file16globalE = dso_local global %"struct.file1::file1_type1" { i32 0, float 1.000000e+00 }, align 4, !dbg !0
+ at _ZN5file25inner12inner_globalE = dso_local global i32 1, align 4, !dbg !11
+
+define dso_local i64 @_Z11file1_func1N5file111file1_type1E(i64 %0) !dbg !33 {
+  %2 = alloca %"struct.file1::file1_type1", align 4
+  %3 = alloca %"struct.file1::file1_type1", align 4
+  store i64 %0, ptr %3, align 4
+    #dbg_declare(ptr %3, !37, !DIExpression(), !38)
+  call void @llvm.memcpy.p0.p0.i64(ptr align 4 %2, ptr align 4 %3, i64 8, i1 false), !dbg !39
+  %4 = load i64, ptr %2, align 4, !dbg !40
+  ret i64 %4, !dbg !40
+}
+
+declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg)
+
+define dso_local <2 x float> @_Z11file2_func1N5file211file2_type1ENS_11file2_type2E(<2 x float> %0, i32 noundef %1) !dbg !41 {
+  %3 = alloca %"struct.file2::file2_type1", align 4
+  %4 = alloca %"struct.file2::file2_type1", align 4
+  %5 = alloca i32, align 4
+  store <2 x float> %0, ptr %4, align 4
+    #dbg_declare(ptr %4, !49, !DIExpression(), !50)
+  store i32 %1, ptr %5, align 4
+    #dbg_declare(ptr %5, !51, !DIExpression(), !52)
+  call void @llvm.memcpy.p0.p0.i64(ptr align 4 %3, ptr align 4 %4, i64 8, i1 false), !dbg !53
+  %6 = load <2 x float>, ptr %3, align 4, !dbg !54
+  ret <2 x float> %6, !dbg !54
+}
+
+!llvm.dbg.cu = !{!20, !22}
+!llvm.ident = !{!25, !25}
+!llvm.module.flags = !{!26, !27, !28, !29, !30, !31, !32}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "global", linkageName: "_ZN5file16globalE", scope: !2, file: !3, line: 6, type: !4, isLocal: false, isDefinition: true)
+!2 = !DINamespace(name: "file1", scope: null)
+!3 = !DIFile(filename: "file1.cpp", directory: "")
+!4 = !DIDerivedType(tag: DW_TAG_typedef, name: "file1_type1", scope: !2, file: !3, line: 5, baseType: !5)
+!5 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "file1_type1", scope: !2, file: !3, line: 5, size: 64, flags: DIFlagTypePassByValue, elements: !6, identifier: "_ZTSN5file111file1_type1E")
+!6 = !{!7, !9}
+!7 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !5, file: !3, line: 5, baseType: !8, size: 32)
+!8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!9 = !DIDerivedType(tag: DW_TAG_member, name: "y", scope: !5, file: !3, line: 5, baseType: !10, size: 32, offset: 32)
+!10 = !DIBasicType(name: "float", size: 32, encoding: DW_ATE_float)
+!11 = !DIGlobalVariableExpression(var: !12, expr: !DIExpression())
+!12 = distinct !DIGlobalVariable(name: "inner_global", linkageName: "_ZN5file25inner12inner_globalE", scope: !13, file: !15, line: 9, type: !16, isLocal: false, isDefinition: true)
+!13 = !DINamespace(name: "inner", scope: !14)
+!14 = !DINamespace(name: "file2", scope: null)
+!15 = !DIFile(filename: "file2.cpp", directory: "")
+!16 = distinct !DICompositeType(tag: DW_TAG_enumeration_type, name: "file2_type2", scope: !14, file: !15, line: 6, baseType: !8, size: 32, flags: DIFlagEnumClass, elements: !17, identifier: "_ZTSN5file211file2_type2E")
+!17 = !{!18, !19}
+!18 = !DIEnumerator(name: "opt1", value: 0)
+!19 = !DIEnumerator(name: "opt2", value: 1)
+!20 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !21, splitDebugInlining: false, nameTableKind: None)
+!21 = !{!0}
+!22 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !15, isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !23, globals: !24, splitDebugInlining: false, nameTableKind: None)
+!23 = !{!16}
+!24 = !{!11}
+!25 = !{!"clang"}
+!26 = !{i32 7, !"Dwarf Version", i32 5}
+!27 = !{i32 2, !"Debug Info Version", i32 3}
+!28 = !{i32 1, !"wchar_size", i32 4}
+!29 = !{i32 8, !"PIC Level", i32 2}
+!30 = !{i32 7, !"PIE Level", i32 2}
+!31 = !{i32 7, !"uwtable", i32 2}
+!32 = !{i32 7, !"frame-pointer", i32 2}
+!33 = distinct !DISubprogram(name: "file1_func1", linkageName: "_Z11file1_func1N5file111file1_type1E", scope: !3, file: !3, line: 11, type: !34, scopeLine: 11, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !20, retainedNodes: !36)
+!34 = !DISubroutineType(types: !35)
+!35 = !{!4, !4}
+!36 = !{}
+!37 = !DILocalVariable(name: "x", arg: 1, scope: !33, file: !3, line: 11, type: !4)
+!38 = !DILocation(line: 11, column: 51, scope: !33)
+!39 = !DILocation(line: 11, column: 63, scope: !33)
+!40 = !DILocation(line: 11, column: 56, scope: !33)
+!41 = distinct !DISubprogram(name: "file2_func1", linkageName: "_Z11file2_func1N5file211file2_type1ENS_11file2_type2E", scope: !15, file: !15, line: 15, type: !42, scopeLine: 15, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !22, retainedNodes: !36)
+!42 = !DISubroutineType(types: !43)
+!43 = !{!44, !44, !16}
+!44 = !DIDerivedType(tag: DW_TAG_typedef, name: "file2_type1", scope: !14, file: !15, line: 5, baseType: !45)
+!45 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "file2_type1", scope: !14, file: !15, line: 5, size: 64, flags: DIFlagTypePassByValue, elements: !46, identifier: "_ZTSN5file211file2_type1E")
+!46 = !{!47, !48}
+!47 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !45, file: !15, line: 5, baseType: !10, size: 32)
+!48 = !DIDerivedType(tag: DW_TAG_member, name: "y", scope: !45, file: !15, line: 5, baseType: !10, size: 32, offset: 32)
+!49 = !DILocalVariable(name: "x", arg: 1, scope: !41, file: !15, line: 15, type: !44)
+!50 = !DILocation(line: 15, column: 51, scope: !41)
+!51 = !DILocalVariable(name: "y", arg: 2, scope: !41, file: !15, line: 15, type: !16)
+!52 = !DILocation(line: 15, column: 73, scope: !41)
+!53 = !DILocation(line: 15, column: 85, scope: !41)
+!54 = !DILocation(line: 15, column: 78, scope: !41)
+)""";
+} // namespace
+} // namespace llvm

``````````

</details>


https://github.com/llvm/llvm-project/pull/118629
