[llvm-objcopy][MachO] Implement --only-section
Reviewers: alexshap, rupprecht, jdoerfert, jhenderson
Reviewed By: alexshap, rupprecht, jhenderson
Subscribers: mgorny, jakehehrlich, abrachet, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65541
diff --git a/llvm/docs/CommandGuide/llvm-objcopy.rst b/llvm/docs/CommandGuide/llvm-objcopy.rst
index 56c3a77..063300a 100644
--- a/llvm/docs/CommandGuide/llvm-objcopy.rst
+++ b/llvm/docs/CommandGuide/llvm-objcopy.rst
@@ -72,6 +72,9 @@
Remove all sections from the output, except for sections named ``<section>``.
Can be specified multiple times to keep multiple sections.
+ For MachO objects, ``<section>`` must be formatted as
+ ``<segment name>,<section name>``.
+
.. option:: --regex
If specified, symbol and section names specified by other switches are treated
diff --git a/llvm/test/tools/llvm-objcopy/MachO/only-section.test b/llvm/test/tools/llvm-objcopy/MachO/only-section.test
new file mode 100644
index 0000000..4e26031
--- /dev/null
+++ b/llvm/test/tools/llvm-objcopy/MachO/only-section.test
@@ -0,0 +1,153 @@
+## Show that if --only-section is given, llvm-objcopy removes all sections
+## except ones specified in the option.
+
+# RUN: yaml2obj %s > %t
+
+## Specify all sections. The output file should be the same as the input.
+# RUN: llvm-objcopy -j __TEXT,__text -j __DATA,__data -j __TEXT,__const %t %t2
+# RUN: cmp %t %t2
+
+## Specify one section. The output file should contain only that section.
+# RUN: llvm-objcopy --only-section __TEXT,__text %t %t3
+# RUN: llvm-readobj --sections --section-data --macho-segment %t3 \
+# RUN: | FileCheck %s --check-prefix=ONLY-TEXT-SECTION
+
+# ONLY-TEXT-SECTION: Sections [
+# ONLY-TEXT-SECTION-NEXT: Section {
+# ONLY-TEXT-SECTION-NEXT: Index: 0
+# ONLY-TEXT-SECTION-NEXT: Name: __text (5F 5F 74 65 78 74 00 00 00 00 00 00 00 00 00 00)
+# ONLY-TEXT-SECTION-NEXT: Segment: __TEXT (5F 5F 54 45 58 54 00 00 00 00 00 00 00 00 00 00)
+# ONLY-TEXT-SECTION-NEXT: Address: 0x0
+# ONLY-TEXT-SECTION-NEXT: Size: 0x4
+# ONLY-TEXT-SECTION-NEXT: Offset: 184
+# ONLY-TEXT-SECTION-NEXT: Alignment: 0
+# ONLY-TEXT-SECTION-NEXT: RelocationOffset: 0x0
+# ONLY-TEXT-SECTION-NEXT: RelocationCount: 0
+# ONLY-TEXT-SECTION-NEXT: Type: Regular (0x0)
+# ONLY-TEXT-SECTION-NEXT: Attributes [ (0x800004)
+# ONLY-TEXT-SECTION-NEXT: PureInstructions (0x800000)
+# ONLY-TEXT-SECTION-NEXT: SomeInstructions (0x4)
+# ONLY-TEXT-SECTION-NEXT: ]
+# ONLY-TEXT-SECTION-NEXT: Reserved1: 0x0
+# ONLY-TEXT-SECTION-NEXT: Reserved2: 0x0
+# ONLY-TEXT-SECTION-NEXT: Reserved3: 0x0
+# ONLY-TEXT-SECTION-NEXT: SectionData (
+# ONLY-TEXT-SECTION-NEXT: 0000: AABBCCDD |....|
+# ONLY-TEXT-SECTION-NEXT: )
+# ONLY-TEXT-SECTION-NEXT: }
+# ONLY-TEXT-SECTION-NEXT: ]
+# ONLY-TEXT-SECTION-NEXT: Segment {
+# ONLY-TEXT-SECTION-NEXT: Cmd: LC_SEGMENT_64
+# ONLY-TEXT-SECTION-NEXT: Name:
+# ONLY-TEXT-SECTION-NEXT: Size: 152
+# ONLY-TEXT-SECTION-NEXT: vmaddr: 0x0
+# ONLY-TEXT-SECTION-NEXT: vmsize: 0x4
+# ONLY-TEXT-SECTION-NEXT: fileoff: 184
+# ONLY-TEXT-SECTION-NEXT: filesize: 4
+# ONLY-TEXT-SECTION-NEXT: maxprot: rwx
+# ONLY-TEXT-SECTION-NEXT: initprot: rwx
+# ONLY-TEXT-SECTION-NEXT: nsects: 1
+# ONLY-TEXT-SECTION-NEXT: flags: 0x0
+# ONLY-TEXT-SECTION-NEXT: }
+
+## Remove all sections if the specified section name is not present in the input.
+# RUN: llvm-objcopy --only-section __TEXT,__nonexistent %t %t4 2>&1
+# RUN: llvm-readobj --sections --section-data --macho-segment %t4 \
+# RUN: | FileCheck %s --check-prefix=NONEXISTENT-SECTION
+
+# NONEXISTENT-SECTION: Sections [
+# NONEXISTENT-SECTION-NEXT: ]
+# NONEXISTENT-SECTION-NEXT: Segment {
+# NONEXISTENT-SECTION-NEXT: Cmd: LC_SEGMENT_64
+# NONEXISTENT-SECTION-NEXT: Name:
+# NONEXISTENT-SECTION-NEXT: Size: 72
+# NONEXISTENT-SECTION-NEXT: vmaddr: 0x0
+# NONEXISTENT-SECTION-NEXT: vmsize: 0x0
+# NONEXISTENT-SECTION-NEXT: fileoff: 104
+# NONEXISTENT-SECTION-NEXT: filesize: 0
+# NONEXISTENT-SECTION-NEXT: maxprot: rwx
+# NONEXISTENT-SECTION-NEXT: initprot: rwx
+# NONEXISTENT-SECTION-NEXT: nsects: 0
+# NONEXISTENT-SECTION-NEXT: flags: 0x0
+# NONEXISTENT-SECTION-NEXT: }
+
+## Use wildcard to specify all sections under the __TEXT segment.
+# RUN: llvm-objcopy --only-section "__TEXT,*" %t %t5 2>&1
+# RUN: llvm-readobj --file-header --sections %t5 \
+# RUN: | FileCheck %s --check-prefix=WILDCARD
+
+## Make sure that it doesn't care about the segment/section name separator ",".
+# RUN: llvm-objcopy --only-section "__TEXT*" %t %t6 2>&1
+# RUN: cmp %t5 %t6
+
+# WILDCARD: NumOfLoadCommands: 1
+# WILDCARD: Sections [
+# WILDCARD: Index: 0
+# WILDCARD-NEXT: Name: __text (5F 5F 74 65 78 74 00 00 00 00 00 00 00 00 00 00)
+# WILDCARD: Index: 1
+# WILDCARD-NEXT: Name: __const (5F 5F 63 6F 6E 73 74 00 00 00 00 00 00 00 00 00)
+# WILDCARD-NOT: Index: 2
+# WILDCARD: ]
+
+--- !mach-o
+FileHeader:
+ magic: 0xFEEDFACF
+ cputype: 0x01000007
+ cpusubtype: 0x00000003
+ filetype: 0x00000001
+ ncmds: 1
+ sizeofcmds: 312
+ flags: 0x00002000
+ reserved: 0x00000000
+LoadCommands:
+ - cmd: LC_SEGMENT_64
+ cmdsize: 312
+ segname: ''
+ vmaddr: 0
+ vmsize: 12
+ fileoff: 344
+ filesize: 12
+ maxprot: 7
+ initprot: 7
+ nsects: 3
+ flags: 0
+ Sections:
+ - sectname: __text
+ segname: __TEXT
+ addr: 0x0000000000000000
+ content: 'AABBCCDD'
+ size: 4
+ offset: 344
+ align: 0
+ reloff: 0x00000000
+ nreloc: 0
+ flags: 0x80000400
+ reserved1: 0x00000000
+ reserved2: 0x00000000
+ reserved3: 0x00000000
+ - sectname: __data
+ segname: __DATA
+ addr: 0x0000000000000004
+ content: 'DDAADDAA'
+ size: 4
+ offset: 348
+ align: 0
+ reloff: 0x00000000
+ nreloc: 0
+ flags: 0x00000000
+ reserved1: 0x00000000
+ reserved2: 0x00000000
+ reserved3: 0x00000000
+ - sectname: __const
+ segname: __TEXT
+ addr: 0x0000000000000008
+ content: 'EEFFEEFF'
+ size: 4
+ offset: 352
+ align: 0
+ reloff: 0x00000000
+ nreloc: 0
+ flags: 0x00000000
+ reserved1: 0x00000000
+ reserved2: 0x00000000
+ reserved3: 0x00000000
diff --git a/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp b/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp
index 6d586e7..73983a1 100644
--- a/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp
+++ b/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp
@@ -18,6 +18,19 @@
namespace macho {
using namespace object;
+using SectionPred = std::function<bool(const Section &Sec)>;
+
+static void removeSections(const CopyConfig &Config, Object &Obj) {
+ SectionPred RemovePred = [](const Section &) { return false; };
+
+ if (!Config.OnlySection.empty()) {
+ RemovePred = [&Config, RemovePred](const Section &Sec) {
+ return !Config.OnlySection.matches(Sec.CanonicalName);
+ };
+ }
+
+ return Obj.removeSections(RemovePred);
+}
static Error handleArgs(const CopyConfig &Config, Object &Obj) {
if (Config.AllowBrokenLinks || !Config.BuildIdLinkDir.empty() ||
@@ -25,11 +38,10 @@
!Config.SplitDWO.empty() || !Config.SymbolsPrefix.empty() ||
!Config.AllocSectionsPrefix.empty() || !Config.AddSection.empty() ||
!Config.DumpSection.empty() || !Config.KeepSection.empty() ||
- Config.NewSymbolVisibility || !Config.OnlySection.empty() ||
- !Config.SymbolsToGlobalize.empty() || !Config.SymbolsToKeep.empty() ||
- !Config.SymbolsToLocalize.empty() || !Config.SymbolsToWeaken.empty() ||
- !Config.SymbolsToKeepGlobal.empty() || !Config.SectionsToRename.empty() ||
- !Config.SymbolsToRename.empty() ||
+ Config.NewSymbolVisibility || !Config.SymbolsToGlobalize.empty() ||
+ !Config.SymbolsToKeep.empty() || !Config.SymbolsToLocalize.empty() ||
+ !Config.SymbolsToWeaken.empty() || !Config.SymbolsToKeepGlobal.empty() ||
+ !Config.SectionsToRename.empty() || !Config.SymbolsToRename.empty() ||
!Config.UnneededSymbolsToRemove.empty() ||
!Config.SetSectionAlignment.empty() || !Config.SetSectionFlags.empty() ||
!Config.ToRemove.empty() || Config.ExtractDWO || Config.KeepFileSymbols ||
@@ -43,6 +55,7 @@
"option not supported by llvm-objcopy for MachO");
}
+ removeSections(Config, Obj);
return Error::success();
}
diff --git a/llvm/tools/llvm-objcopy/MachO/MachOReader.cpp b/llvm/tools/llvm-objcopy/MachO/MachOReader.cpp
index b48a0d8..ed2b3eb 100644
--- a/llvm/tools/llvm-objcopy/MachO/MachOReader.cpp
+++ b/llvm/tools/llvm-objcopy/MachO/MachOReader.cpp
@@ -35,6 +35,7 @@
.str();
S.Segname =
StringRef(Sec.segname, strnlen(Sec.segname, sizeof(Sec.sectname))).str();
+ S.CanonicalName = (Twine(S.Segname) + "," + S.Sectname).str();
S.Addr = Sec.addr;
S.Size = Sec.size;
S.Offset = Sec.offset;
diff --git a/llvm/tools/llvm-objcopy/MachO/Object.cpp b/llvm/tools/llvm-objcopy/MachO/Object.cpp
index 264f39c..ba3e2ef 100644
--- a/llvm/tools/llvm-objcopy/MachO/Object.cpp
+++ b/llvm/tools/llvm-objcopy/MachO/Object.cpp
@@ -10,6 +10,13 @@
return Symbols[Index].get();
}
+void Object::removeSections(function_ref<bool(const Section &)> ToRemove) {
+ for (LoadCommand &LC : LoadCommands)
+ LC.Sections.erase(std::remove_if(std::begin(LC.Sections),
+ std::end(LC.Sections), ToRemove),
+ std::end(LC.Sections));
+}
+
} // end namespace macho
} // end namespace objcopy
} // end namespace llvm
diff --git a/llvm/tools/llvm-objcopy/MachO/Object.h b/llvm/tools/llvm-objcopy/MachO/Object.h
index 1cebf82..36b0f7e 100644
--- a/llvm/tools/llvm-objcopy/MachO/Object.h
+++ b/llvm/tools/llvm-objcopy/MachO/Object.h
@@ -38,6 +38,8 @@
struct Section {
std::string Sectname;
std::string Segname;
+ // CanonicalName is a string formatted as “<Segname>,<Sectname>".
+ std::string CanonicalName;
uint64_t Addr;
uint64_t Size;
uint32_t Offset;
@@ -250,6 +252,8 @@
Optional<size_t> DataInCodeCommandIndex;
/// The index LC_FUNCTION_STARTS load comamnd if present.
Optional<size_t> FunctionStartsCommandIndex;
+
+ void removeSections(function_ref<bool(const Section &)> ToRemove);
};
} // end namespace macho