Reland "[llvm-objcopy] Add support for --strip-sections to remove all section headers leaving only program headers and loadable segment data"
ubsan caught an issue I made where I was converting a null pointer to a
reference.
elf utils implements a particularly extreme form of stripping that I'd
like to support. eu-strip has an option called "strip-sections" that
removes all section headers and leaves only program headers and the
segment data. I have implemented this option partly as a test but mainly
because in Fuchsia we would like to use this option to minimize the size
of our executables. The other strip options that are on my list include
--strip-all and --strip-debug. This is a preliminary implementation that
I'd like to start using in Fuchsia builds if possible. This change
implements such a stripping option for llvm-objcopy
Differential Revision: https://reviews.llvm.org/D38335
llvm-svn: 315484
diff --git a/llvm/test/tools/llvm-objcopy/strip-sections.test b/llvm/test/tools/llvm-objcopy/strip-sections.test
new file mode 100644
index 0000000..66cb34e
--- /dev/null
+++ b/llvm/test/tools/llvm-objcopy/strip-sections.test
@@ -0,0 +1,66 @@
+# RUN: yaml2obj %s > %t
+# RUN: llvm-objcopy --strip-sections %t %t2
+# RUN: llvm-readobj -file-headers -program-headers %t2 | FileCheck %s
+# RUN: od -t x1 -j 4096 %t2 | FileCheck %s --check-prefix=DATA
+
+!ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_EXEC
+ Machine: EM_X86_64
+Sections:
+ - Name: .text
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+ AddressAlign: 0x0000000000001000
+ Content: "DEADBEEF"
+ProgramHeaders:
+- Type: PT_LOAD
+ Flags: [ PF_X, PF_R ]
+ Sections:
+ - Section: .text
+
+#DATA: 0010000 de ad be ef
+
+#CHECK: ElfHeader {
+#CHECK-NEXT: Ident {
+#CHECK-NEXT: Magic: (7F 45 4C 46)
+#CHECK-NEXT: Class: 64-bit (0x2)
+#CHECK-NEXT: DataEncoding: LittleEndian (0x1)
+#CHECK-NEXT: FileVersion: 1
+#CHECK-NEXT: OS/ABI: SystemV (0x0)
+#CHECK-NEXT: ABIVersion: 0
+#CHECK-NEXT: Unused: (00 00 00 00 00 00 00)
+#CHECK-NEXT: }
+#CHECK-NEXT: Type: Executable (0x2)
+#CHECK-NEXT: Machine: EM_X86_64 (0x3E)
+#CHECK-NEXT: Version: 1
+#CHECK-NEXT: Entry: 0x0
+#CHECK-NEXT: ProgramHeaderOffset: 0x40
+#CHECK-NEXT: SectionHeaderOffset: 0x0
+#CHECK-NEXT: Flags [ (0x0)
+#CHECK-NEXT: ]
+#CHECK-NEXT: HeaderSize: 64
+#CHECK-NEXT: ProgramHeaderEntrySize: 56
+#CHECK-NEXT: ProgramHeaderCount: 1
+#CHECK-NEXT: SectionHeaderEntrySize: 64
+#CHECK-NEXT: SectionHeaderCount: 0
+#CHECK-NEXT: StringTableSectionIndex: 0
+#CHECK-NEXT: }
+
+#CHECK: ProgramHeaders [
+#CHECK-NEXT: ProgramHeader {
+#CHECK-NEXT: Type: PT_LOAD (0x1)
+#CHECK-NEXT: Offset: 0x1000
+#CHECK-NEXT: VirtualAddress: 0x0
+#CHECK-NEXT: PhysicalAddress: 0x0
+#CHECK-NEXT: FileSize: 4
+#CHECK-NEXT: MemSize: 4
+#CHECK-NEXT: Flags [ (0x5)
+#CHECK-NEXT: PF_R (0x4)
+#CHECK-NEXT: PF_X (0x1)
+#CHECK-NEXT: ]
+#CHECK-NEXT: Alignment: 4096
+#CHECK-NEXT: }
+#CHECK-NEXT:]