[llvm] r364898 - [yaml2obj] - Allow overriding sh_offset field from the YAML.
George Rimar via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 2 03:20:12 PDT 2019
Author: grimar
Date: Tue Jul 2 03:20:12 2019
New Revision: 364898
URL: http://llvm.org/viewvc/llvm-project?rev=364898&view=rev
Log:
[yaml2obj] - Allow overriding sh_offset field from the YAML.
Some of our test cases are using objects which
has sections with a broken sh_offset field.
There was no way to set it from YAML until this patch.
Differential revision: https://reviews.llvm.org/D63879
Added:
llvm/trunk/test/tools/yaml2obj/elf-override-shoffset.yaml
Modified:
llvm/trunk/include/llvm/ObjectYAML/ELFYAML.h
llvm/trunk/lib/ObjectYAML/ELFYAML.cpp
llvm/trunk/tools/obj2yaml/elf2yaml.cpp
llvm/trunk/tools/yaml2obj/yaml2elf.cpp
Modified: llvm/trunk/include/llvm/ObjectYAML/ELFYAML.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ObjectYAML/ELFYAML.h?rev=364898&r1=364897&r2=364898&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ObjectYAML/ELFYAML.h (original)
+++ llvm/trunk/include/llvm/ObjectYAML/ELFYAML.h Tue Jul 2 03:20:12 2019
@@ -140,6 +140,10 @@ struct Section {
llvm::yaml::Hex64 AddressAlign;
Optional<llvm::yaml::Hex64> EntSize;
+ // This can be used to override the sh_offset field. It does not place the
+ // section data at the offset specified. Useful for creating invalid objects.
+ Optional<llvm::yaml::Hex64> ShOffset;
+
Section(SectionKind Kind) : Kind(Kind) {}
virtual ~Section();
};
Modified: llvm/trunk/lib/ObjectYAML/ELFYAML.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ObjectYAML/ELFYAML.cpp?rev=364898&r1=364897&r2=364898&view=diff
==============================================================================
--- llvm/trunk/lib/ObjectYAML/ELFYAML.cpp (original)
+++ llvm/trunk/lib/ObjectYAML/ELFYAML.cpp Tue Jul 2 03:20:12 2019
@@ -911,6 +911,12 @@ static void commonSectionMapping(IO &IO,
IO.mapOptional("Link", Section.Link, StringRef());
IO.mapOptional("AddressAlign", Section.AddressAlign, Hex64(0));
IO.mapOptional("EntSize", Section.EntSize);
+
+ // obj2yaml does not dump this field. It is expected to be empty when we are
+ // producing YAML, because yaml2obj sets an appropriate value for sh_offset
+ // automatically when it is not explicitly defined.
+ assert(!IO.outputting() || !Section.ShOffset.hasValue());
+ IO.mapOptional("ShOffset", Section.ShOffset);
}
static void sectionMapping(IO &IO, ELFYAML::DynamicSection &Section) {
Added: llvm/trunk/test/tools/yaml2obj/elf-override-shoffset.yaml
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/yaml2obj/elf-override-shoffset.yaml?rev=364898&view=auto
==============================================================================
--- llvm/trunk/test/tools/yaml2obj/elf-override-shoffset.yaml (added)
+++ llvm/trunk/test/tools/yaml2obj/elf-override-shoffset.yaml Tue Jul 2 03:20:12 2019
@@ -0,0 +1,106 @@
+## Check we are able to set custom sh_offset field
+## for different sections.
+
+# RUN: yaml2obj --docnum=1 %s -o %t1
+# RUN: llvm-readelf --sections %t1 | FileCheck %s --check-prefix=CASE1
+
+# CASE1: Section Headers:
+# CASE1-NEXT: [Nr] Name Type Address Off
+# CASE1-NEXT: [ 0] NULL {{.*}} 000000
+# CASE1-NEXT: [ 1] .dynsym DYNSYM {{.*}} 000001
+# CASE1-NEXT: [ 2] .symtab SYMTAB {{.*}} 000002
+# CASE1-NEXT: [ 3] .dynamic DYNAMIC {{.*}} 000003
+# CASE1-NEXT: [ 4] .rela RELA {{.*}} 000004
+# CASE1-NEXT: [ 5] .nobits NOBITS {{.*}} 000005
+# CASE1-NEXT: [ 6] .group GROUP {{.*}} 000006
+# CASE1-NEXT: [ 7] .gnu.version VERSYM {{.*}} 000007
+# CASE1-NEXT: [ 8] .gnu.version_r VERNEED {{.*}} 000008
+# CASE1-NEXT: [ 9] .gnu.version_d VERDEF {{.*}} 000009
+# CASE1-NEXT: [10] .regular PROGBITS {{.*}} 00000a
+# CASE1-NEXT: [11] .strtab STRTAB {{.*}} 00000b
+
+--- !ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_REL
+ Machine: EM_X86_64
+Sections:
+ - Name: .dynsym
+ Type: SHT_DYNSYM
+ ShOffset: 0x000000001
+ - Name: .symtab
+ Type: SHT_SYMTAB
+ ShOffset: 0x000000002
+ - Name: .dynamic
+ Type: SHT_DYNAMIC
+ ShOffset: 0x000000003
+ - Name: .rela
+ Type: SHT_RELA
+ ShOffset: 0x000000004
+ - Name: .nobits
+ Type: SHT_NOBITS
+ ShOffset: 0x000000005
+ - Name: .group
+ Type: SHT_GROUP
+ Info: 0
+ ShOffset: 0x000000006
+ Members:
+ - Name: .gnu.version
+ Type: SHT_GNU_versym
+ Entries: [ ]
+ ShOffset: 0x000000007
+ - Name: .gnu.version_r
+ Type: SHT_GNU_verneed
+ Info: 0x0000000000000001
+ ShOffset: 0x000000008
+ Dependencies:
+ - Name: .gnu.version_d
+ Type: SHT_GNU_verdef
+ Info: 0x0000000000000001
+ ShOffset: 0x000000009
+ Entries:
+ - Name: .regular
+ Type: SHT_PROGBITS
+ ShOffset: 0x00000000A
+ - Name: .strtab
+ Type: SHT_STRTAB
+ ShOffset: 0x00000000B
+
+## Here we check that defining ShOffset does not actually change
+## the offset at which section data is placed and also does
+## not affect file size.
+
+# RUN: yaml2obj --docnum=2 %s -o %t2
+# RUN: yaml2obj --docnum=3 %s -o %t3
+# RUN: od -t x8 -v %t2 > %t.txt
+# RUN: od -t x8 -v %t3 >> %t.txt
+# RUN: FileCheck %s --input-file=%t.txt --check-prefix=CASE2
+
+# CASE2: [[OFFSET:.*]] 8877665544332211
+# CASE2: [[FILESIZE:.*]]{{$}}
+# CASE2: [[OFFSET]] 8877665544332211
+# CASE2: [[FILESIZE]]{{$}}
+
+--- !ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_REL
+ Machine: EM_X86_64
+Sections:
+ - Name: .foo
+ Type: SHT_PROGBITS
+ Content: "1122334455667788"
+
+--- !ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_REL
+ Machine: EM_X86_64
+Sections:
+ - Name: .foo
+ Type: SHT_PROGBITS
+ ShOffset: 0xFFFF0000
+ Content: "1122334455667788"
Modified: llvm/trunk/tools/obj2yaml/elf2yaml.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/obj2yaml/elf2yaml.cpp?rev=364898&r1=364897&r2=364898&view=diff
==============================================================================
--- llvm/trunk/tools/obj2yaml/elf2yaml.cpp (original)
+++ llvm/trunk/tools/obj2yaml/elf2yaml.cpp Tue Jul 2 03:20:12 2019
@@ -360,6 +360,8 @@ std::error_code ELFDumper<ELFT>::dumpRel
template <class ELFT>
std::error_code ELFDumper<ELFT>::dumpCommonSection(const Elf_Shdr *Shdr,
ELFYAML::Section &S) {
+ // Dump fields. We do not dump the ShOffset field. When not explicitly
+ // set, the value is set by yaml2obj automatically.
S.Type = Shdr->sh_type;
if (Shdr->sh_flags)
S.Flags = static_cast<ELFYAML::ELF_SHF>(Shdr->sh_flags);
Modified: llvm/trunk/tools/yaml2obj/yaml2elf.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/yaml2obj/yaml2elf.cpp?rev=364898&r1=364897&r2=364898&view=diff
==============================================================================
--- llvm/trunk/tools/yaml2obj/yaml2elf.cpp (original)
+++ llvm/trunk/tools/yaml2obj/yaml2elf.cpp Tue Jul 2 03:20:12 2019
@@ -269,6 +269,11 @@ bool ELFState<ELFT>::initImplicitHeader(
YAMLSec);
else
return false;
+
+ // Override the sh_offset field if requested.
+ if (YAMLSec && YAMLSec->ShOffset)
+ Header.sh_offset = *YAMLSec->ShOffset;
+
return true;
}
@@ -358,6 +363,10 @@ bool ELFState<ELFT>::initSectionHeaders(
return false;
} else
llvm_unreachable("Unknown section type");
+
+ // Override the sh_offset field if requested.
+ if (Sec && Sec->ShOffset)
+ SHeader.sh_offset = *Sec->ShOffset;
}
return true;
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