[Lldb-commits] [lldb] [lldb] Avoid force loading symbols in statistics collection (PR #136236)
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lldb-commits at lists.llvm.org
Sat Apr 19 10:44:45 PDT 2025
https://github.com/royitaqi updated https://github.com/llvm/llvm-project/pull/136236
>From 85cb8cca4fe41cf4080b3dbf7ce4f98c4b15a3c7 Mon Sep 17 00:00:00 2001
From: Roy Shi <royshi at meta.com>
Date: Thu, 17 Apr 2025 15:03:00 -0700
Subject: [PATCH 1/5] [lldb] Do not parse symtab during statistics dump
Summary:
Test Plan:
Reviewers:
Subscribers:
Tasks:
Tags:
Differential Revision: https://phabricator.intern.facebook.com/D73218490
---
lldb/include/lldb/Symbol/ObjectFile.h | 2 +-
lldb/include/lldb/Symbol/SymbolFile.h | 4 ++--
lldb/include/lldb/Symbol/SymbolFileOnDemand.h | 2 +-
lldb/source/Core/Module.cpp | 2 +-
lldb/source/Symbol/ObjectFile.cpp | 4 ++--
lldb/source/Symbol/SymbolFile.cpp | 4 ++--
6 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/lldb/include/lldb/Symbol/ObjectFile.h b/lldb/include/lldb/Symbol/ObjectFile.h
index cfcca04a76de8..7fca6383fa9f3 100644
--- a/lldb/include/lldb/Symbol/ObjectFile.h
+++ b/lldb/include/lldb/Symbol/ObjectFile.h
@@ -319,7 +319,7 @@ class ObjectFile : public std::enable_shared_from_this<ObjectFile>,
///
/// \return
/// The symbol table for this object file.
- Symtab *GetSymtab();
+ Symtab *GetSymtab(bool can_create = true);
/// Parse the symbol table into the provides symbol table object.
///
diff --git a/lldb/include/lldb/Symbol/SymbolFile.h b/lldb/include/lldb/Symbol/SymbolFile.h
index f35d3ee9f22ae..df2f263b18e17 100644
--- a/lldb/include/lldb/Symbol/SymbolFile.h
+++ b/lldb/include/lldb/Symbol/SymbolFile.h
@@ -144,7 +144,7 @@ class SymbolFile : public PluginInterface {
virtual uint32_t GetNumCompileUnits() = 0;
virtual lldb::CompUnitSP GetCompileUnitAtIndex(uint32_t idx) = 0;
- virtual Symtab *GetSymtab() = 0;
+ virtual Symtab *GetSymtab(bool can_create = true) = 0;
virtual lldb::LanguageType ParseLanguage(CompileUnit &comp_unit) = 0;
/// Return the Xcode SDK comp_unit was compiled against.
@@ -533,7 +533,7 @@ class SymbolFileCommon : public SymbolFile {
return m_abilities;
}
- Symtab *GetSymtab() override;
+ Symtab *GetSymtab(bool can_create = true) override;
ObjectFile *GetObjectFile() override { return m_objfile_sp.get(); }
const ObjectFile *GetObjectFile() const override {
diff --git a/lldb/include/lldb/Symbol/SymbolFileOnDemand.h b/lldb/include/lldb/Symbol/SymbolFileOnDemand.h
index 7a366bfabec86..ce9fc8626ac34 100644
--- a/lldb/include/lldb/Symbol/SymbolFileOnDemand.h
+++ b/lldb/include/lldb/Symbol/SymbolFileOnDemand.h
@@ -186,7 +186,7 @@ class SymbolFileOnDemand : public lldb_private::SymbolFile {
uint32_t GetAbilities() override;
- Symtab *GetSymtab() override { return m_sym_file_impl->GetSymtab(); }
+ Symtab *GetSymtab(bool can_create = true) override { return m_sym_file_impl->GetSymtab(can_create); }
ObjectFile *GetObjectFile() override {
return m_sym_file_impl->GetObjectFile();
diff --git a/lldb/source/Core/Module.cpp b/lldb/source/Core/Module.cpp
index ad7046e596278..625c14e4a2153 100644
--- a/lldb/source/Core/Module.cpp
+++ b/lldb/source/Core/Module.cpp
@@ -997,7 +997,7 @@ SymbolFile *Module::GetSymbolFile(bool can_create, Stream *feedback_strm) {
Symtab *Module::GetSymtab(bool can_create) {
if (SymbolFile *symbols = GetSymbolFile(can_create))
- return symbols->GetSymtab();
+ return symbols->GetSymtab(can_create);
return nullptr;
}
diff --git a/lldb/source/Symbol/ObjectFile.cpp b/lldb/source/Symbol/ObjectFile.cpp
index 2f2c59d6af620..292c00b9ac166 100644
--- a/lldb/source/Symbol/ObjectFile.cpp
+++ b/lldb/source/Symbol/ObjectFile.cpp
@@ -735,9 +735,9 @@ void llvm::format_provider<ObjectFile::Strata>::format(
}
-Symtab *ObjectFile::GetSymtab() {
+Symtab *ObjectFile::GetSymtab(bool can_create) {
ModuleSP module_sp(GetModule());
- if (module_sp) {
+ if (module_sp && can_create) {
// We can't take the module lock in ObjectFile::GetSymtab() or we can
// deadlock in DWARF indexing when any file asks for the symbol table from
// an object file. This currently happens in the preloading of symbols in
diff --git a/lldb/source/Symbol/SymbolFile.cpp b/lldb/source/Symbol/SymbolFile.cpp
index 94e32b55572dd..870d778dca740 100644
--- a/lldb/source/Symbol/SymbolFile.cpp
+++ b/lldb/source/Symbol/SymbolFile.cpp
@@ -152,10 +152,10 @@ void SymbolFile::AssertModuleLock() {
SymbolFile::RegisterInfoResolver::~RegisterInfoResolver() = default;
-Symtab *SymbolFileCommon::GetSymtab() {
+Symtab *SymbolFileCommon::GetSymtab(bool can_create) {
std::lock_guard<std::recursive_mutex> guard(GetModuleMutex());
// Fetch the symtab from the main object file.
- auto *symtab = GetMainObjectFile()->GetSymtab();
+ auto *symtab = GetMainObjectFile()->GetSymtab(can_create);
if (m_symtab != symtab) {
m_symtab = symtab;
>From 1fccd09dde2d1f8da6f8253516c5c908049eb270 Mon Sep 17 00:00:00 2001
From: Roy Shi <royshi at meta.com>
Date: Thu, 17 Apr 2025 21:45:48 -0700
Subject: [PATCH 2/5] Fix compilation of a unit test
---
lldb/unittests/Symbol/LineTableTest.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lldb/unittests/Symbol/LineTableTest.cpp b/lldb/unittests/Symbol/LineTableTest.cpp
index f67ac46c738e7..eadab40a37fac 100644
--- a/lldb/unittests/Symbol/LineTableTest.cpp
+++ b/lldb/unittests/Symbol/LineTableTest.cpp
@@ -58,7 +58,7 @@ class FakeSymbolFile : public SymbolFile {
uint32_t CalculateAbilities() override { return UINT32_MAX; }
uint32_t GetNumCompileUnits() override { return 1; }
CompUnitSP GetCompileUnitAtIndex(uint32_t) override { return m_cu_sp; }
- Symtab *GetSymtab() override { return nullptr; }
+ Symtab *GetSymtab(bool can_create = true) override { return nullptr; }
LanguageType ParseLanguage(CompileUnit &) override { return eLanguageTypeC; }
size_t ParseFunctions(CompileUnit &) override { return 0; }
bool ParseLineTable(CompileUnit &) override { return true; }
>From 2c80507e49724a70688225c44e75400a18884e09 Mon Sep 17 00:00:00 2001
From: Roy Shi <royshi at meta.com>
Date: Thu, 17 Apr 2025 22:38:57 -0700
Subject: [PATCH 3/5] Fixing format (hopefully) and trying to add a test
---
lldb/include/lldb/Symbol/SymbolFileOnDemand.h | 4 +++-
lldb/source/Symbol/ObjectFile.cpp | 1 -
lldb/unittests/Symbol/SymtabTest.cpp | 14 ++++++++++++--
3 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/lldb/include/lldb/Symbol/SymbolFileOnDemand.h b/lldb/include/lldb/Symbol/SymbolFileOnDemand.h
index ce9fc8626ac34..6ed389a48880c 100644
--- a/lldb/include/lldb/Symbol/SymbolFileOnDemand.h
+++ b/lldb/include/lldb/Symbol/SymbolFileOnDemand.h
@@ -186,7 +186,9 @@ class SymbolFileOnDemand : public lldb_private::SymbolFile {
uint32_t GetAbilities() override;
- Symtab *GetSymtab(bool can_create = true) override { return m_sym_file_impl->GetSymtab(can_create); }
+ Symtab *GetSymtab(bool can_create = true) override {
+ return m_sym_file_impl->GetSymtab(can_create);
+ }
ObjectFile *GetObjectFile() override {
return m_sym_file_impl->GetObjectFile();
diff --git a/lldb/source/Symbol/ObjectFile.cpp b/lldb/source/Symbol/ObjectFile.cpp
index 292c00b9ac166..afd0d298e675e 100644
--- a/lldb/source/Symbol/ObjectFile.cpp
+++ b/lldb/source/Symbol/ObjectFile.cpp
@@ -734,7 +734,6 @@ void llvm::format_provider<ObjectFile::Strata>::format(
}
}
-
Symtab *ObjectFile::GetSymtab(bool can_create) {
ModuleSP module_sp(GetModule());
if (module_sp && can_create) {
diff --git a/lldb/unittests/Symbol/SymtabTest.cpp b/lldb/unittests/Symbol/SymtabTest.cpp
index e431c31e1eac1..05208ca07ee08 100644
--- a/lldb/unittests/Symbol/SymtabTest.cpp
+++ b/lldb/unittests/Symbol/SymtabTest.cpp
@@ -721,7 +721,7 @@ TEST_F(SymtabTest, TestDecodeCStringMaps) {
ASSERT_NE(symbol, nullptr);
}
-TEST_F(SymtabTest, TestSymtabCreatedOnDemand) {
+TEST_F(SymtabTest, TestSymbolFileAndSymbolTableCreatedOnDemand) {
auto ExpectedFile = TestFile::fromYaml(R"(
--- !ELF
FileHeader:
@@ -749,10 +749,20 @@ TEST_F(SymtabTest, TestSymtabCreatedOnDemand) {
ASSERT_THAT_EXPECTED(ExpectedFile, llvm::Succeeded());
auto module_sp = std::make_shared<Module>(ExpectedFile->moduleSpec());
- // The symbol table should not be loaded by default.
+ // The symbol file should not be created by default.
Symtab *module_symtab = module_sp->GetSymtab(/*can_create=*/false);
ASSERT_EQ(module_symtab, nullptr);
+ // Even if the symbol file is created, the symbol table should not be created by default.
+
+ // TODO:
+ // I need to create a symbol file here, but without causing it to parse the symbol table.
+ // See next line as a failed attempt.
+
+ // module_sp->GetSymbolFile(/*can_create=*/true); // Cannot do this because it will parse the symbol table.
+ module_symtab = module_sp->GetSymtab(/*can_create=*/false);
+ ASSERT_EQ(module_symtab, nullptr);
+
// But it should be created on demand.
module_symtab = module_sp->GetSymtab(/*can_create=*/true);
ASSERT_NE(module_symtab, nullptr);
>From 34dc7de6b6a696957e2968817011a0bccff1ba5f Mon Sep 17 00:00:00 2001
From: Roy Shi <royshi at meta.com>
Date: Sat, 19 Apr 2025 10:40:23 -0700
Subject: [PATCH 4/5] Add unit test
---
lldb/unittests/Symbol/SymtabTest.cpp | 83 ++++++++++++++++++++++++----
1 file changed, 72 insertions(+), 11 deletions(-)
diff --git a/lldb/unittests/Symbol/SymtabTest.cpp b/lldb/unittests/Symbol/SymtabTest.cpp
index 05208ca07ee08..dbc3be9190568 100644
--- a/lldb/unittests/Symbol/SymtabTest.cpp
+++ b/lldb/unittests/Symbol/SymtabTest.cpp
@@ -721,7 +721,7 @@ TEST_F(SymtabTest, TestDecodeCStringMaps) {
ASSERT_NE(symbol, nullptr);
}
-TEST_F(SymtabTest, TestSymbolFileAndSymbolTableCreatedOnDemand) {
+TEST_F(SymtabTest, TestSymbolFileCreatedOnDemand) {
auto ExpectedFile = TestFile::fromYaml(R"(
--- !ELF
FileHeader:
@@ -753,16 +753,6 @@ TEST_F(SymtabTest, TestSymbolFileAndSymbolTableCreatedOnDemand) {
Symtab *module_symtab = module_sp->GetSymtab(/*can_create=*/false);
ASSERT_EQ(module_symtab, nullptr);
- // Even if the symbol file is created, the symbol table should not be created by default.
-
- // TODO:
- // I need to create a symbol file here, but without causing it to parse the symbol table.
- // See next line as a failed attempt.
-
- // module_sp->GetSymbolFile(/*can_create=*/true); // Cannot do this because it will parse the symbol table.
- module_symtab = module_sp->GetSymtab(/*can_create=*/false);
- ASSERT_EQ(module_symtab, nullptr);
-
// But it should be created on demand.
module_symtab = module_sp->GetSymtab(/*can_create=*/true);
ASSERT_NE(module_symtab, nullptr);
@@ -771,3 +761,74 @@ TEST_F(SymtabTest, TestSymbolFileAndSymbolTableCreatedOnDemand) {
Symtab *cached_module_symtab = module_sp->GetSymtab(/*can_create=*/false);
ASSERT_EQ(module_symtab, cached_module_symtab);
}
+
+TEST_F(SymtabTest, TestSymbolTableCreatedOnDemand) {
+ const char *yamldata = R"(
+--- !ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_EXEC
+ Machine: EM_386
+DWARF:
+ debug_abbrev:
+ - Table:
+ - Code: 0x00000001
+ Tag: DW_TAG_compile_unit
+ Children: DW_CHILDREN_no
+ Attributes:
+ - Attribute: DW_AT_addr_base
+ Form: DW_FORM_sec_offset
+ debug_info:
+ - Version: 5
+ AddrSize: 4
+ UnitType: DW_UT_compile
+ Entries:
+ - AbbrCode: 0x00000001
+ Values:
+ - Value: 0x8 # Offset of the first Address past the header
+ - AbbrCode: 0x0
+ debug_addr:
+ - Version: 5
+ AddressSize: 4
+ Entries:
+ - Address: 0x1234
+ - Address: 0x5678
+ debug_line:
+ - Length: 42
+ Version: 2
+ PrologueLength: 36
+ MinInstLength: 1
+ DefaultIsStmt: 1
+ LineBase: 251
+ LineRange: 14
+ OpcodeBase: 13
+ StandardOpcodeLengths: [ 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1 ]
+ IncludeDirs:
+ - '/tmp'
+ Files:
+ - Name: main.cpp
+ DirIdx: 1
+ ModTime: 0
+ Length: 0
+)";
+ llvm::Expected<TestFile> file = TestFile::fromYaml(yamldata);
+ EXPECT_THAT_EXPECTED(file, llvm::Succeeded());
+ auto module_sp = std::make_shared<Module>(file->moduleSpec());
+
+ SymbolFile* symbol_file = module_sp->GetSymbolFile();
+ // At this point, the symbol table is not created. This is because the above yaml data contains the necessary sections in order for SymbolFileDWARF::CalculateAbilities() to identify all abilities,
+ // saving the code from calling SymbolFileDWARFDebugMap::CalculateAbilities(), which eventually loads the symbol table, which we don't want.
+
+ // The symbol table should not be created if asked not to.
+ Symtab* symtab = symbol_file->GetSymtab(/*can_create=*/false);
+ ASSERT_EQ(symtab, nullptr);
+
+ // But it should be created on demand.
+ symtab = symbol_file->GetSymtab(/*can_create=*/true);
+ ASSERT_NE(symtab, nullptr);
+
+ // And we should be able to get it again once it has been created.
+ symtab = symbol_file->GetSymtab(/*can_create=*/false);
+ ASSERT_NE(symtab, nullptr);
+}
>From afeaa369a65e91065394261ce29bce1b92047a62 Mon Sep 17 00:00:00 2001
From: Roy Shi <royshi at meta.com>
Date: Sat, 19 Apr 2025 10:43:16 -0700
Subject: [PATCH 5/5] Fix format
---
lldb/unittests/Symbol/SymtabTest.cpp | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/lldb/unittests/Symbol/SymtabTest.cpp b/lldb/unittests/Symbol/SymtabTest.cpp
index dbc3be9190568..3af708b0bc8d3 100644
--- a/lldb/unittests/Symbol/SymtabTest.cpp
+++ b/lldb/unittests/Symbol/SymtabTest.cpp
@@ -816,12 +816,15 @@ TEST_F(SymtabTest, TestSymbolTableCreatedOnDemand) {
EXPECT_THAT_EXPECTED(file, llvm::Succeeded());
auto module_sp = std::make_shared<Module>(file->moduleSpec());
- SymbolFile* symbol_file = module_sp->GetSymbolFile();
- // At this point, the symbol table is not created. This is because the above yaml data contains the necessary sections in order for SymbolFileDWARF::CalculateAbilities() to identify all abilities,
- // saving the code from calling SymbolFileDWARFDebugMap::CalculateAbilities(), which eventually loads the symbol table, which we don't want.
+ SymbolFile *symbol_file = module_sp->GetSymbolFile();
+ // At this point, the symbol table is not created. This is because the above
+ // yaml data contains the necessary sections in order for
+ // SymbolFileDWARF::CalculateAbilities() to identify all abilities, saving it
+ // from calling SymbolFileDWARFDebugMap::CalculateAbilities(), which
+ // eventually loads the symbol table, which we don't want.
// The symbol table should not be created if asked not to.
- Symtab* symtab = symbol_file->GetSymtab(/*can_create=*/false);
+ Symtab *symtab = symbol_file->GetSymtab(/*can_create=*/false);
ASSERT_EQ(symtab, nullptr);
// But it should be created on demand.
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