[llvm-objcopy] Add support for --strip-sections to remove all section headers leaving only program headers and loadable segment data

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315412 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 66 insertions, 0 deletions

diff --git a/test/tools/llvm-objcopy/strip-sections.test b/test/tools/llvm-objcopy/strip-sections.test
new file mode 100644
index 00000000000..66cb34e89b0
--- /dev/null
+++ b/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:]