llvm-project/lld/test/MachO/symtab.s

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[lld-macho][reland] Add basic symbol table output This diff implements basic support for writing a symbol table. Attributes are loosely supported for extern symbols and not at all for other types. Initial version by Kellie Medlin <kelliem@fb.com> Originally committed in a3d95a50ee33 and reverted in fbae153ca583 due to UBSAN erroring over unaligned writes. That has been fixed in the current diff with the following changes: ``` diff --git a/lld/MachO/SyntheticSections.cpp b/lld/MachO/SyntheticSections.cpp --- a/lld/MachO/SyntheticSections.cpp +++ b/lld/MachO/SyntheticSections.cpp @@ -133,6 +133,9 @@ SymtabSection::SymtabSection(StringTableSection &stringTableSection) : stringTableSection(stringTableSection) { segname = segment_names::linkEdit; name = section_names::symbolTable; + // TODO: When we introduce the SyntheticSections superclass, we should make + // all synthetic sections aligned to WordSize by default. + align = WordSize; } size_t SymtabSection::getSize() const { diff --git a/lld/MachO/Writer.cpp b/lld/MachO/Writer.cpp --- a/lld/MachO/Writer.cpp +++ b/lld/MachO/Writer.cpp @@ -371,6 +371,7 @@ void Writer::assignAddresses(OutputSegment *seg) { ArrayRef<InputSection *> sections = p.second; for (InputSection *isec : sections) { addr = alignTo(addr, isec->align); + // We must align the file offsets too to avoid misaligned writes of + // structs. + fileOff = alignTo(fileOff, isec->align); isec->addr = addr; addr += isec->getSize(); fileOff += isec->getFileSize(); @@ -396,6 +397,7 @@ void Writer::writeSections() { uint64_t fileOff = seg->fileOff; for (auto &sect : seg->getSections()) { for (InputSection *isec : sect.second) { + fileOff = alignTo(fileOff, isec->align); isec->writeTo(buf + fileOff); fileOff += isec->getFileSize(); } ``` I don't think it's easy to write a test for alignment (that doesn't involve brittly hard-coding file offsets), so there isn't one... but UBSAN builds pass now. Differential Revision: https://reviews.llvm.org/D79050
2020-04-29 07:58:19 +08:00
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o
# RUN: lld -flavor darwinnew -o %t %t.o
# RUN: llvm-readobj -symbols %t | FileCheck %s
# CHECK: Symbols [
# CHECK-NEXT: Symbol {
# CHECK-NEXT: Name: _main
# CHECK-NEXT: Extern
# CHECK-NEXT: Type: Section (0xE)
# CHECK-NEXT: Section: __text (0x1)
# CHECK-NEXT: RefType:
# CHECK-NEXT: Flags [ (0x0)
# CHECK-NEXT: ]
# CHECK-NEXT: Value:
# CHECK-NEXT: }
# CHECK-NEXT: Symbol {
# CHECK-NEXT: Name: bar
# CHECK-NEXT: Extern
# CHECK-NEXT: Type: Section (0xE)
# CHECK-NEXT: Section: __text (0x1)
# CHECK-NEXT: RefType:
# CHECK-NEXT: Flags [ (0x0)
# CHECK-NEXT: ]
# CHECK-NEXT: Value:
# CHECK-NEXT: }
# CHECK-NEXT: Symbol {
# CHECK-NEXT: Name: foo
# CHECK-NEXT: Extern
# CHECK-NEXT: Type: Section (0xE)
# CHECK-NEXT: Section: __data
# CHECK-NEXT: RefType:
# CHECK-NEXT: Flags [ (0x0)
# CHECK-NEXT: ]
# CHECK-NEXT: Value:
# CHECK-NEXT: }
[lld-macho][reland] Add basic symbol table output This diff implements basic support for writing a symbol table. Attributes are loosely supported for extern symbols and not at all for other types. Initial version by Kellie Medlin <kelliem@fb.com> Originally committed in a3d95a50ee33 and reverted in fbae153ca583 due to UBSAN erroring over unaligned writes. That has been fixed in the current diff with the following changes: ``` diff --git a/lld/MachO/SyntheticSections.cpp b/lld/MachO/SyntheticSections.cpp --- a/lld/MachO/SyntheticSections.cpp +++ b/lld/MachO/SyntheticSections.cpp @@ -133,6 +133,9 @@ SymtabSection::SymtabSection(StringTableSection &stringTableSection) : stringTableSection(stringTableSection) { segname = segment_names::linkEdit; name = section_names::symbolTable; + // TODO: When we introduce the SyntheticSections superclass, we should make + // all synthetic sections aligned to WordSize by default. + align = WordSize; } size_t SymtabSection::getSize() const { diff --git a/lld/MachO/Writer.cpp b/lld/MachO/Writer.cpp --- a/lld/MachO/Writer.cpp +++ b/lld/MachO/Writer.cpp @@ -371,6 +371,7 @@ void Writer::assignAddresses(OutputSegment *seg) { ArrayRef<InputSection *> sections = p.second; for (InputSection *isec : sections) { addr = alignTo(addr, isec->align); + // We must align the file offsets too to avoid misaligned writes of + // structs. + fileOff = alignTo(fileOff, isec->align); isec->addr = addr; addr += isec->getSize(); fileOff += isec->getFileSize(); @@ -396,6 +397,7 @@ void Writer::writeSections() { uint64_t fileOff = seg->fileOff; for (auto &sect : seg->getSections()) { for (InputSection *isec : sect.second) { + fileOff = alignTo(fileOff, isec->align); isec->writeTo(buf + fileOff); fileOff += isec->getFileSize(); } ``` I don't think it's easy to write a test for alignment (that doesn't involve brittly hard-coding file offsets), so there isn't one... but UBSAN builds pass now. Differential Revision: https://reviews.llvm.org/D79050
2020-04-29 07:58:19 +08:00
# CHECK-NEXT: ]
.data
.global foo
foo:
.asciz "Hello world!\n"
.text
.global bar
[lld-macho][reland] Add basic symbol table output This diff implements basic support for writing a symbol table. Attributes are loosely supported for extern symbols and not at all for other types. Initial version by Kellie Medlin <kelliem@fb.com> Originally committed in a3d95a50ee33 and reverted in fbae153ca583 due to UBSAN erroring over unaligned writes. That has been fixed in the current diff with the following changes: ``` diff --git a/lld/MachO/SyntheticSections.cpp b/lld/MachO/SyntheticSections.cpp --- a/lld/MachO/SyntheticSections.cpp +++ b/lld/MachO/SyntheticSections.cpp @@ -133,6 +133,9 @@ SymtabSection::SymtabSection(StringTableSection &stringTableSection) : stringTableSection(stringTableSection) { segname = segment_names::linkEdit; name = section_names::symbolTable; + // TODO: When we introduce the SyntheticSections superclass, we should make + // all synthetic sections aligned to WordSize by default. + align = WordSize; } size_t SymtabSection::getSize() const { diff --git a/lld/MachO/Writer.cpp b/lld/MachO/Writer.cpp --- a/lld/MachO/Writer.cpp +++ b/lld/MachO/Writer.cpp @@ -371,6 +371,7 @@ void Writer::assignAddresses(OutputSegment *seg) { ArrayRef<InputSection *> sections = p.second; for (InputSection *isec : sections) { addr = alignTo(addr, isec->align); + // We must align the file offsets too to avoid misaligned writes of + // structs. + fileOff = alignTo(fileOff, isec->align); isec->addr = addr; addr += isec->getSize(); fileOff += isec->getFileSize(); @@ -396,6 +397,7 @@ void Writer::writeSections() { uint64_t fileOff = seg->fileOff; for (auto &sect : seg->getSections()) { for (InputSection *isec : sect.second) { + fileOff = alignTo(fileOff, isec->align); isec->writeTo(buf + fileOff); fileOff += isec->getFileSize(); } ``` I don't think it's easy to write a test for alignment (that doesn't involve brittly hard-coding file offsets), so there isn't one... but UBSAN builds pass now. Differential Revision: https://reviews.llvm.org/D79050
2020-04-29 07:58:19 +08:00
.global _main
_main:
mov $0, %rax
ret
bar:
mov $2, %rax
ret