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Revert "[LLDB][ELF] Load both, .symtab and .dynsym sections" 

This reverts commit 3a4781bbf4.

llvm-svn: 371625
This commit is contained in:
Konrad Kleine 2019-09-11 14:33:37 +00:00
parent d44c4a71df
commit 2f3884ca1d
6 changed files with 9 additions and 119 deletions
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7
lldb/lit/Modules/ELF/Inputs/load-from-dynsym-alone.c
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@ -1,7 +0,0 @@
// This function will be embedded within the .dynsym section of the main binary.
int functionInDynsym(int num) { return num * 3; }
int main(int argc, char *argv[]) {
int y = functionInDynsym(argc);
return y;
}

12
lldb/lit/Modules/ELF/Inputs/load-symtab-and-dynsym.c
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@ -1,12 +0,0 @@
// This function will be embedded within the .symtab section of the
// .gnu_debugdata section.
int functionInSymtab(int num) { return num * 4; }
// This function will be embedded within the .dynsym section of the main binary.
int functionInDynsym(int num) { return num * 3; }
int main(int argc, char *argv[]) {
int x = functionInSymtab(argc);
int y = functionInDynsym(x);
return y;
}

33
lldb/lit/Modules/ELF/load-from-dynsym-alone.test
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@ -1,33 +0,0 @@
# REQUIRES: system-linux
# This test ensures that we will load .dynsym even if there's no .symtab section.
# We do this by compiling a small C program with a function and we direct the
# linker where to put the symbols so that in the end the layout is as follows:
#
# Symbol table '.dynsym' contains 4 entries:
# Num: Value Size Type Bind Vis Ndx Name
# 0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
# 1: 0000000000000000 0 FUNC GLOBAL DEFAULT UND __libc_start_main@GLIBC_2.2.5
# 2: 0000000000000000 0 NOTYPE WEAK DEFAULT UND __gmon_start__
# 3: 0000000000401110 13 FUNC GLOBAL DEFAULT 10 functionInDynsym
# We want to keep the symbol "functionInDynsym" in the .dynamic section and not
# have it put the default .symtab section.
# RUN: echo "{functionInDynsym;};" > %T/dynmic-symbols.txt
# RUN: %clang -Wl,--dynamic-list=%T/dynmic-symbols.txt -g -o %t.binary %p/Inputs/load-from-dynsym-alone.c
# Remove not needed symbols
# RUN: echo "functionInDynsym" > %t.keep_symbols
# RUN: llvm-objcopy --strip-all --remove-section .gdb_index --remove-section .comment --keep-symbols=%t.keep_symbols %t.binary
# Remove functionInDynsym symbol from .symtab (will leave symbol in .dynsym intact)
# RUN: llvm-strip --strip-symbol=functionInDynsym %t.binary
# RUN: %lldb -b -o 'b functionInDynsym' -o 'run' -o 'continue' %t.binary | FileCheck %s
# CHECK: (lldb) b functionInDynsym
# CHECK-NEXT: Breakpoint 1: where = {{.*}}.binary`functionInDynsym, address = 0x{{.*}}
# CHECK: (lldb) run
# CHECK-NEXT: Process {{.*}} stopped
# CHECK-NEXT: * thread #1, name = 'load-from-dynsy', stop reason = breakpoint 1.1

48
lldb/lit/Modules/ELF/load-symtab-and-dynsym.test
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@ -1,48 +0,0 @@
# REQUIRES: system-linux
# This test ensures that we will load .dynsym even if there's a .symtab section.
# We do this by compiling a small C program with two functions and we direct the
# linker where to put the symbols so that in the end the layout is as follows:
#
# Symbol table '.dynsym' contains 4 entries:
# Num: Value Size Type Bind Vis Ndx Name
# 0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
# 1: 0000000000000000 0 FUNC GLOBAL DEFAULT UND __libc_start_main@GLIBC_2.2.5
# 2: 0000000000000000 0 NOTYPE WEAK DEFAULT UND __gmon_start__
# 3: 0000000000401120 13 FUNC GLOBAL DEFAULT 10 functionInDynsym
#
# Symbol table '.symtab' contains 2 entries:
# Num: Value Size Type Bind Vis Ndx Name
# 0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
# 1: 0000000000401110 15 FUNC GLOBAL DEFAULT 10 functionInSymtab
# We want to keep the symbol "functionInDynsym" in the .dynamic section and not
# have it put the default .symtab section.
# RUN: echo "{functionInDynsym;};" > %T/dynmic-symbols.txt
# RUN: %clang -Wl,--dynamic-list=%T/dynmic-symbols.txt -g -o %t.binary %p/Inputs/load-symtab-and-dynsym.c
# Remove not needed symbols
# RUN: echo "functionInSymtab" > %t.keep_symbols
# RUN: echo "functionInDynsym" >> %t.keep_symbols
# RUN: llvm-objcopy --strip-all --remove-section .gdb_index --remove-section .comment --keep-symbols=%t.keep_symbols %t.binary
# Remove functionInDynsym symbol from .symtab (will leave symbol in .dynsym intact)
# RUN: llvm-strip --strip-symbol=functionInDynsym %t.binary
# RUN: %lldb -b -o 'b functionInSymtab' -o 'b functionInDynsym' -o 'run' -o 'continue' %t.binary | FileCheck %s
# CHECK: (lldb) b functionInSymtab
# CHECK-NEXT: Breakpoint 1: where = {{.*}}.binary`functionInSymtab, address = 0x{{.*}}
# CHECK: (lldb) b functionInDynsym
# CHECK-NEXT: Breakpoint 2: where = {{.*}}.binary`functionInDynsym, address = 0x{{.*}}
# CHECK: (lldb) run
# CHECK-NEXT: Process {{.*}} stopped
# CHECK-NEXT: * thread #1, name = 'load-symtab-and', stop reason = breakpoint 1.1
# CHECK: (lldb) continue
# CHECK-NEXT: Process {{.*}} resuming
# CHECK-NEXT: Process {{.*}} stopped
# CHECK-NEXT: * thread #1, name = 'load-symtab-and', stop reason = breakpoint 2.1

2
lldb/lit/helper/toolchain.py
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@ -126,6 +126,6 @@ def use_support_substitutions(config):
support_tools = ['yaml2obj', 'obj2yaml', 'llvm-pdbutil', support_tools = ['yaml2obj', 'obj2yaml', 'llvm-pdbutil',
'llvm-mc', 'llvm-readobj', 'llvm-objdump', 'llvm-mc', 'llvm-readobj', 'llvm-objdump',
'llvm-objcopy', 'lli', 'llvm-strip'] 'llvm-objcopy', 'lli']
additional_tool_dirs += [config.lldb_tools_dir, config.llvm_tools_dir] additional_tool_dirs += [config.lldb_tools_dir, config.llvm_tools_dir]
llvm_config.add_tool_substitutions(support_tools, additional_tool_dirs) llvm_config.add_tool_substitutions(support_tools, additional_tool_dirs)

26
lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
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@ -2647,31 +2647,21 @@ Symtab *ObjectFileELF::GetSymtab() {
// smaller version of the symtab that only contains global symbols. The // smaller version of the symtab that only contains global symbols. The
// information found in the dynsym is therefore also found in the symtab, // information found in the dynsym is therefore also found in the symtab,
// while the reverse is not necessarily true. // while the reverse is not necessarily true.
// One exception to the above rule is when we have minidebuginfo embedded
// into a compressed .gnu_debugdata section. This section contains a .symtab
// from which all symbols already contained in the .dynsym are stripped.
Section *symtab = Section *symtab =
section_list->FindSectionByType(eSectionTypeELFSymbolTable, true).get(); section_list->FindSectionByType(eSectionTypeELFSymbolTable, true).get();
if (!symtab) {
// The symtab section is non-allocable and can be stripped, so if it
// doesn't exist then use the dynsym section which should always be
// there.
symtab =
section_list->FindSectionByType(eSectionTypeELFDynamicSymbols, true)
.get();
}
if (symtab) { if (symtab) {
m_symtab_up.reset(new Symtab(symtab->GetObjectFile())); m_symtab_up.reset(new Symtab(symtab->GetObjectFile()));
symbol_id += ParseSymbolTable(m_symtab_up.get(), symbol_id, symtab); symbol_id += ParseSymbolTable(m_symtab_up.get(), symbol_id, symtab);
} }
// The symtab section is non-allocable and can be stripped, while the dynsym
// section which should always be always be there. If both exist we load
// both to support the minidebuginfo case. Otherwise we just load the dynsym
// section.
Section *dynsym =
section_list->FindSectionByType(eSectionTypeELFDynamicSymbols, true)
.get();
if (dynsym) {
if (!m_symtab_up) {
auto sec = symtab ? symtab : dynsym;
m_symtab_up.reset(new Symtab(sec->GetObjectFile()));
}
symbol_id += ParseSymbolTable(m_symtab_up.get(), symbol_id, dynsym);
}
// DT_JMPREL // DT_JMPREL
// If present, this entry's d_ptr member holds the address of // If present, this entry's d_ptr member holds the address of
// relocation // relocation