This revision was automatically updated to reflect the committed changes.
Closed by commit rGf0697d7c3fb5: Don't create sections for SHN_ABS symbols
in ELF files. (authored by clayborg).
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D131705/new/
https://reviews.llvm.org/D131705
Files:
lldb/bindings/interface/SBSymbol.i
lldb/include/lldb/API/SBSymbol.h
lldb/include/lldb/Symbol/Symbol.h
lldb/source/API/SBSymbol.cpp
lldb/source/Commands/CommandObjectTarget.cpp
lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
lldb/source/Symbol/Symbol.cpp
lldb/test/API/python_api/absolute_symbol/TestAbsoluteSymbol.py
lldb/test/API/python_api/absolute_symbol/absolute.yaml
lldb/test/Shell/SymbolFile/absolute-symbol.test
Index: lldb/test/Shell/SymbolFile/absolute-symbol.test
===================================================================
--- lldb/test/Shell/SymbolFile/absolute-symbol.test
+++ lldb/test/Shell/SymbolFile/absolute-symbol.test
@@ -1,8 +1,7 @@
# RUN: yaml2obj %s -o %t.o
# RUN: %lldb -b -o 'target modules lookup -s absolute_symbol' %t.o | FileCheck %s
# CHECK: 1 symbols match 'absolute_symbol'
-# CHECK: Address: 0x0000000012345678 (0x0000000012345678)
-# CHECK: Summary: 0x0000000012345678
+# CHECK: Value: 0x0000000012345678
# Created from:
# .globl absolute_symbol
# absolute_symbol = 0x12345678
@@ -92,4 +91,3 @@
- ltmp0
- ''
...
-
Index: lldb/test/API/python_api/absolute_symbol/absolute.yaml
===================================================================
--- /dev/null
+++ lldb/test/API/python_api/absolute_symbol/absolute.yaml
@@ -0,0 +1,36 @@
+--- !ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ OSABI: ELFOSABI_FREEBSD
+ Type: ET_EXEC
+ Machine: EM_X86_64
+ Entry: 0xFFFFFFFF8037C000
+Sections:
+ - Name: .text
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+ Address: 0x1000
+ AddressAlign: 0x4
+ Content: "c3c3c3c3"
+ProgramHeaders:
+ - Type: PT_LOAD
+ Flags: [ PF_X, PF_R ]
+ VAddr: 0x1000
+ PAddr: 0x1000
+ Align: 0x4
+ FirstSec: .text
+ LastSec: .text
+Symbols:
+ - Name: main
+ Type: STT_FUNC
+ Section: .text
+ Binding: STB_GLOBAL
+ Value: 0x1000
+ Size: 0x4
+ - Name: absolute
+ Index: SHN_ABS
+ Binding: STB_GLOBAL
+ Value: 0xFFFFFFFF80000000
+ Size: 0x9
+
Index: lldb/test/API/python_api/absolute_symbol/TestAbsoluteSymbol.py
===================================================================
--- /dev/null
+++ lldb/test/API/python_api/absolute_symbol/TestAbsoluteSymbol.py
@@ -0,0 +1,80 @@
+"""
+Test absolute symbols in ELF files to make sure they don't create sections and
+to verify that symbol values and size can still be accessed via SBSymbol APIs.
+"""
+
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+import os
+
+class TestAbsoluteSymbol(TestBase):
+
+ @no_debug_info_test
+ def test_absolute_symbol(self):
+ '''
+ Load an ELF file that contains two symbols:
+ - "absolute" which is a symbol with the section SHN_ABS
+ - "main" which is a code symbol in .text
+
+ Index st_name st_value st_size st_info st_other st_shndx Name
+ ======= ---------- ------------------ ------------------ ----------------------------------- -------- -------- ===========================
+ [ 0] 0x00000000 0x0000000000000000 0x0000000000000000 0x00 (STB_LOCAL STT_NOTYPE ) 0x00 0
+ [ 1] 0x00000001 0x0000000000001000 0x0000000000000004 0x12 (STB_GLOBAL STT_FUNC ) 0x00 1 main
+ [ 2] 0x00000006 0xffffffff80000000 0x0000000000000009 0x10 (STB_GLOBAL STT_NOTYPE ) 0x00 SHN_ABS absolute
+
+ We used to create sections for symbols whose section ID was SHN_ABS
+ and this caused problems as the new sections could interfere with
+ with address resolution. Absolute symbols' values are not addresses
+ and should not be treated this way.
+
+ New APIs were added to SBSymbol to allow access to the raw integer
+ value and size of symbols so symbols whose value was not an address
+ could be accessed. Prior to this commit, you could only call:
+
+ SBAddress SBSymbol::GetStartAddress()
+ SBAddress SBSymbol::GetEndAddress()
+
+ If the symbol's value was not an address, you couldn't access the
+ raw value because the above accessors would return invalid SBAddress
+ objects if the value wasn't an address. New APIs were added for this:
+
+ uint64_t SBSymbol::GetValue()
+ uint64_t SBSymbol::GetSize();
+ '''
+ src_dir = self.getSourceDir()
+ yaml_path = os.path.join(src_dir, "absolute.yaml")
+ yaml_base, ext = os.path.splitext(yaml_path)
+ obj_path = self.getBuildArtifact("a.out")
+ self.yaml2obj(yaml_path, obj_path)
+
+ # Create a target with the object file we just created from YAML
+ target = self.dbg.CreateTarget(obj_path)
+ self.assertTrue(target, VALID_TARGET)
+
+ module = target.modules[0]
+
+ # Make sure the 'main' symbol is valid and has address values. Also make
+ # sure we can access the raw file address and size via the new APIS.
+ symbol = module.FindSymbol('main')
+ self.assertTrue(symbol.IsValid())
+ self.assertTrue(symbol.GetStartAddress().IsValid())
+ self.assertTrue(symbol.GetEndAddress().IsValid())
+ self.assertEqual(symbol.GetValue(), 0x1000)
+ self.assertEqual(symbol.GetSize(), 0x4)
+
+ # Make sure the 'absolute' symbol is valid and has no address values.
+ # Also make sure we can access the raw file address and size via the new
+ # APIS.
+ symbol = module.FindSymbol('absolute')
+ self.assertTrue(symbol.IsValid())
+ self.assertFalse(symbol.GetStartAddress().IsValid())
+ self.assertFalse(symbol.GetEndAddress().IsValid())
+ self.assertEqual(symbol.GetValue(), 0xffffffff80000000)
+ self.assertEqual(symbol.GetSize(), 9)
+
+ # Make sure no sections were created for the absolute symbol with a
+ # prefix of ".absolute." followed by the symbol name as they interfere
+ # with address lookups if they are treated like real sections.
+ for section in module.sections:
+ self.assertTrue(section.GetName() != ".absolute.absolute")
Index: lldb/source/Symbol/Symbol.cpp
===================================================================
--- lldb/source/Symbol/Symbol.cpp
+++ lldb/source/Symbol/Symbol.cpp
@@ -115,8 +115,7 @@
}
bool Symbol::ValueIsAddress() const {
- return m_addr_range.GetBaseAddress().GetSection().get() != nullptr ||
- m_type == eSymbolTypeAbsolute;
+ return (bool)m_addr_range.GetBaseAddress().GetSection();
}
ConstString Symbol::GetDisplayName() const {
Index: lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
===================================================================
--- lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -2223,23 +2223,6 @@
// symbols. See above for more details.
uint64_t symbol_value = symbol.st_value + symbol_value_offset;
- if (symbol_section_sp == nullptr && shndx == SHN_ABS &&
- symbol.st_size != 0) {
- // We don't have a section for a symbol with non-zero size. Create a new
- // section for it so the address range covered by the symbol is also
- // covered by the module (represented through the section list). It is
- // needed so module lookup for the addresses covered by this symbol will
- // be successfull. This case happens for absolute symbols.
- ConstString fake_section_name(std::string(".absolute.") + symbol_name);
- symbol_section_sp =
- std::make_shared<Section>(module_sp, this, SHN_ABS, fake_section_name,
- eSectionTypeAbsoluteAddress, symbol_value,
- symbol.st_size, 0, 0, 0, SHF_ALLOC);
-
- module_section_list->AddSection(symbol_section_sp);
- section_list->AddSection(symbol_section_sp);
- }
-
if (symbol_section_sp &&
CalculateType() != ObjectFile::Type::eTypeObjectFile)
symbol_value -= symbol_section_sp->GetFileAddress();
Index: lldb/source/Commands/CommandObjectTarget.cpp
===================================================================
--- lldb/source/Commands/CommandObjectTarget.cpp
+++ lldb/source/Commands/CommandObjectTarget.cpp
@@ -1541,10 +1541,20 @@
strm.IndentMore();
for (uint32_t i = 0; i < num_matches; ++i) {
Symbol *symbol = symtab->SymbolAtIndex(match_indexes[i]);
- if (symbol && symbol->ValueIsAddress()) {
- DumpAddress(
- interpreter.GetExecutionContext().GetBestExecutionContextScope(),
- symbol->GetAddressRef(), verbose, all_ranges, strm);
+ if (symbol) {
+ if (symbol->ValueIsAddress()) {
+ DumpAddress(
+ interpreter.GetExecutionContext().GetBestExecutionContextScope(),
+ symbol->GetAddressRef(), verbose, all_ranges, strm);
+ } else {
+ strm.IndentMore();
+ strm.Indent(" Value: ");
+ strm.Printf("0x%16.16" PRIx64 "\n", symbol->GetRawValue());
+ if (symbol->GetByteSizeIsValid()) {
+ strm.Indent(" Size: ");
+ strm.Printf("0x%16.16" PRIx64 "\n", symbol->GetByteSize());
+ }
+ }
}
}
strm.IndentLess();
Index: lldb/source/API/SBSymbol.cpp
===================================================================
--- lldb/source/API/SBSymbol.cpp
+++ lldb/source/API/SBSymbol.cpp
@@ -162,6 +162,20 @@
return addr;
}
+uint64_t SBSymbol::GetValue() {
+ LLDB_INSTRUMENT_VA(this);
+ if (m_opaque_ptr)
+ return m_opaque_ptr->GetRawValue();
+ return 0;
+}
+
+uint64_t SBSymbol::GetSize() {
+ LLDB_INSTRUMENT_VA(this);
+ if (m_opaque_ptr && m_opaque_ptr->GetByteSizeIsValid())
+ return m_opaque_ptr->GetByteSize();
+ return 0;
+}
+
uint32_t SBSymbol::GetPrologueByteSize() {
LLDB_INSTRUMENT_VA(this);
Index: lldb/include/lldb/Symbol/Symbol.h
===================================================================
--- lldb/include/lldb/Symbol/Symbol.h
+++ lldb/include/lldb/Symbol/Symbol.h
@@ -85,6 +85,16 @@
return Address();
}
+ /// Get the raw value of the symbol from the symbol table.
+ ///
+ /// If the symbol's value is an address, return the file address, else return
+ /// the raw value that is stored in the m_addr_range. If the base address has
+ /// no section, then getting the file address will return the correct value
+ /// as it will return the offset in the base address which is the value.
+ uint64_t GetRawValue() const {
+ return m_addr_range.GetBaseAddress().GetFileAddress();
+ }
+
// When a symbol's value isn't an address, we need to access the raw value.
// This function will ensure this symbol's value isn't an address and return
// the integer value if this checks out, otherwise it will return
Index: lldb/include/lldb/API/SBSymbol.h
===================================================================
--- lldb/include/lldb/API/SBSymbol.h
+++ lldb/include/lldb/API/SBSymbol.h
@@ -41,10 +41,46 @@
lldb::SBInstructionList GetInstructions(lldb::SBTarget target,
const char *flavor_string);
+ /// Get the start address of this symbol
+ ///
+ /// \returns
+ /// If the symbol's value is not an address, an invalid SBAddress object
+ /// will be returned. If the symbol's value is an address, a valid SBAddress
+ /// object will be returned.
SBAddress GetStartAddress();
+ /// Get the end address of this symbol
+ ///
+ /// \returns
+ /// If the symbol's value is not an address, an invalid SBAddress object
+ /// will be returned. If the symbol's value is an address, a valid SBAddress
+ /// object will be returned.
SBAddress GetEndAddress();
+ /// Get the raw value of a symbol.
+ ///
+ /// This accessor allows direct access to the symbol's value from the symbol
+ /// table regardless of what the value is. The value can be a file address or
+ /// it can be an integer value that depends on what the symbol's type is. Some
+ /// symbol values are not addresses, but absolute values or integer values
+ /// that can be mean different things. The GetStartAddress() accessor will
+ /// only return a valid SBAddress if the symbol's value is an address, so this
+ /// accessor provides a way to access the symbol's value when the value is
+ /// not an address.
+ ///
+ /// \returns
+ /// Returns the raw integer value of a symbol from the symbol table.
+ uint64_t GetValue();
+
+ /// Get the size of the symbol.
+ ///
+ /// This accessor allows direct access to the symbol's size from the symbol
+ /// table regardless of what the value is (address or integer value).
+ ///
+ /// \returns
+ /// Returns the size of a symbol from the symbol table.
+ uint64_t GetSize();
+
uint32_t GetPrologueByteSize();
SymbolType GetType();
Index: lldb/bindings/interface/SBSymbol.i
===================================================================
--- lldb/bindings/interface/SBSymbol.i
+++ lldb/bindings/interface/SBSymbol.i
@@ -49,6 +49,10 @@
SBAddress
GetEndAddress ();
+ uint64_t GetValue();
+
+ uint64_t GetSize();
+
uint32_t
GetPrologueByteSize ();
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