[llvm] 1560a00 - [yaml2obj/obj2yaml/llvm-readobj] Support SHF_GNU_RETAIN
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 2 09:20:00 PST 2021
Author: Fangrui Song
Date: 2021-02-02T09:19:53-08:00
New Revision: 1560a0003224cf20d14a71521d4f36fd150f8206
URL: https://github.com/llvm/llvm-project/commit/1560a0003224cf20d14a71521d4f36fd150f8206
DIFF: https://github.com/llvm/llvm-project/commit/1560a0003224cf20d14a71521d4f36fd150f8206.diff
LOG: [yaml2obj/obj2yaml/llvm-readobj] Support SHF_GNU_RETAIN
In binutils, the flag is defined for ELFOSABI_GNU and ELFOSABI_FREEBSD.
It can be used to mark a section as a GC root.
In practice, the flag has generic semantics and can be applied to many
EI_OSABI values, so we consider it generic.
Differential Revision: https://reviews.llvm.org/D95728
Added:
Modified:
llvm/include/llvm/BinaryFormat/ELF.h
llvm/lib/ObjectYAML/ELFYAML.cpp
llvm/test/tools/llvm-readobj/ELF/gnu-sections.test
llvm/test/tools/llvm-readobj/ELF/section-flags-os-proc.test
llvm/test/tools/llvm-readobj/ELF/section-flags.test
llvm/tools/llvm-readobj/ELFDumper.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/BinaryFormat/ELF.h b/llvm/include/llvm/BinaryFormat/ELF.h
index 1552303b610ca..e66f6cec9186d 100644
--- a/llvm/include/llvm/BinaryFormat/ELF.h
+++ b/llvm/include/llvm/BinaryFormat/ELF.h
@@ -949,6 +949,9 @@ enum : unsigned {
// Identifies a section containing compressed data.
SHF_COMPRESSED = 0x800U,
+ // This section should not be garbage collected by the linker.
+ SHF_GNU_RETAIN = 0x200000,
+
// This section is excluded from the final executable or shared library.
SHF_EXCLUDE = 0x80000000U,
diff --git a/llvm/lib/ObjectYAML/ELFYAML.cpp b/llvm/lib/ObjectYAML/ELFYAML.cpp
index 21ff9b8afd175..10a19fa58d2e8 100644
--- a/llvm/lib/ObjectYAML/ELFYAML.cpp
+++ b/llvm/lib/ObjectYAML/ELFYAML.cpp
@@ -555,6 +555,7 @@ void ScalarBitSetTraits<ELFYAML::ELF_SHF>::bitset(IO &IO,
BCase(SHF_GROUP);
BCase(SHF_TLS);
BCase(SHF_COMPRESSED);
+ BCase(SHF_GNU_RETAIN);
switch (Object->getMachine()) {
case ELF::EM_ARM:
BCase(SHF_ARM_PURECODE);
diff --git a/llvm/test/tools/llvm-readobj/ELF/gnu-sections.test b/llvm/test/tools/llvm-readobj/ELF/gnu-sections.test
index ab6ea13c3a66c..02d082329c3d8 100644
--- a/llvm/test/tools/llvm-readobj/ELF/gnu-sections.test
+++ b/llvm/test/tools/llvm-readobj/ELF/gnu-sections.test
@@ -23,7 +23,7 @@
# ELF32-NEXT: W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
# ELF32-NEXT: L (link order), O (extra OS processing required), G (group), T (TLS),
# ELF32-NEXT: C (compressed), x (unknown), o (OS specific), E (exclude),
-# ELF32-NEXT: p (processor specific)
+# ELF32-NEXT: R (retain), p (processor specific)
--- !ELF
FileHeader:
@@ -97,7 +97,7 @@ Symbols:
# ELF64-NEXT: W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
# ELF64-NEXT: L (link order), O (extra OS processing required), G (group), T (TLS),
# ELF64-NEXT: C (compressed), x (unknown), o (OS specific), E (exclude),
-# ELF64-NEXT: l (large), p (processor specific)
+# ELF64-NEXT: R (retain), l (large), p (processor specific)
## For an EM_ARM target we print "y" for the SHF_ARM_PURECODE section flag.
## Check we mention it in the flag key.
@@ -109,4 +109,4 @@ Symbols:
# ARM-NEXT: W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
# ARM-NEXT: L (link order), O (extra OS processing required), G (group), T (TLS),
# ARM-NEXT: C (compressed), x (unknown), o (OS specific), E (exclude),
-# ARM-NEXT: y (purecode), p (processor specific)
+# ARM-NEXT: R (retain), y (purecode), p (processor specific)
diff --git a/llvm/test/tools/llvm-readobj/ELF/section-flags-os-proc.test b/llvm/test/tools/llvm-readobj/ELF/section-flags-os-proc.test
index f96acdd1f3ba1..b8096611b3ef6 100644
--- a/llvm/test/tools/llvm-readobj/ELF/section-flags-os-proc.test
+++ b/llvm/test/tools/llvm-readobj/ELF/section-flags-os-proc.test
@@ -11,10 +11,12 @@
# OS-PROC-LLVM: Name: .os.flags.high
# OS-PROC-LLVM-NEXT: Type: SHT_PROGBITS
# OS-PROC-LLVM-NEXT: Flags [ (0xFE00000)
+# OS-PROC-LLVM-NEXT: SHF_GNU_RETAIN (0x200000)
# OS-PROC-LLVM-NEXT: ]
# OS-PROC-LLVM: Name: .os.flags.mask
# OS-PROC-LLVM-NEXT: Type: SHT_PROGBITS
# OS-PROC-LLVM-NEXT: Flags [ (0xFF00000)
+# OS-PROC-LLVM-NEXT: SHF_GNU_RETAIN (0x200000)
# OS-PROC-LLVM-NEXT: ]
# OS-PROC-LLVM: Name: .proc.flags.low
# OS-PROC-LLVM-NEXT: Type: SHT_PROGBITS
@@ -38,11 +40,13 @@
# OS-PROC-LLVM-NEXT: Type: SHT_PROGBITS
# OS-PROC-LLVM-NEXT: Flags [ (0xEFE00000)
# OS-PROC-LLVM-NEXT: SHF_EXCLUDE (0x80000000)
+# OS-PROC-LLVM-NEXT: SHF_GNU_RETAIN (0x200000)
# OS-PROC-LLVM-NEXT: ]
# OS-PROC-LLVM: Name: .both.flags.mask
# OS-PROC-LLVM-NEXT: Type: SHT_PROGBITS
# OS-PROC-LLVM-NEXT: Flags [ (0xFFF00000)
# OS-PROC-LLVM-NEXT: SHF_EXCLUDE (0x80000000)
+# OS-PROC-LLVM-NEXT: SHF_GNU_RETAIN (0x200000)
# OS-PROC-LLVM-NEXT: ]
# OS-PROC-LLVM: Name: .exclude
# OS-PROC-LLVM-NEXT: Type: SHT_PROGBITS
@@ -56,6 +60,7 @@
# OS-PROC-LLVM-NEXT: SHF_COMPRESSED (0x800)
# OS-PROC-LLVM-NEXT: SHF_EXCLUDE (0x80000000)
# OS-PROC-LLVM-NEXT: SHF_EXECINSTR (0x4)
+# OS-PROC-LLVM-NEXT: SHF_GNU_RETAIN (0x200000)
# OS-PROC-LLVM-NEXT: SHF_GROUP (0x200)
# OS-PROC-LLVM-NEXT: SHF_INFO_LINK (0x40)
# OS-PROC-LLVM-NEXT: SHF_LINK_ORDER (0x80)
@@ -70,13 +75,13 @@
# OS-PROC-GNU-NEXT: [Nr] Name Type Address Off Size ES Flg Lk Inf Al
# OS-PROC-GNU-NEXT: [ 0] NULL 0000000000000000 000000 000000 00 0 0 0
# OS-PROC-GNU-NEXT: [ 1] .os.flags.low PROGBITS 0000000000000000 000040 000000 00 o 0 0 0
-# OS-PROC-GNU-NEXT: [ 2] .os.flags.high PROGBITS 0000000000000000 000040 000000 00 o 0 0 0
+# OS-PROC-GNU-NEXT: [ 2] .os.flags.high PROGBITS 0000000000000000 000040 000000 00 Ro 0 0 0
# OS-PROC-GNU-NEXT: [ 3] .os.flags.mask PROGBITS 0000000000000000 000040 000000 00 o 0 0 0
# OS-PROC-GNU-NEXT: [ 4] .proc.flags.low PROGBITS 0000000000000000 000040 000000 00 p 0 0 0
# OS-PROC-GNU-NEXT: [ 5] .proc.flags.high PROGBITS 0000000000000000 000040 000000 00 p 0 0 0
# OS-PROC-GNU-NEXT: [ 6] .proc.flags.mask PROGBITS 0000000000000000 000040 000000 00 p 0 0 0
# OS-PROC-GNU-NEXT: [ 7] .both.flags.low PROGBITS 0000000000000000 000040 000000 00 op 0 0 0
-# OS-PROC-GNU-NEXT: [ 8] .both.flags.high PROGBITS 0000000000000000 000040 000000 00 op 0 0 0
+# OS-PROC-GNU-NEXT: [ 8] .both.flags.high PROGBITS 0000000000000000 000040 000000 00 Rop 0 0 0
# OS-PROC-GNU-NEXT: [ 9] .both.flags.mask PROGBITS 0000000000000000 000040 000000 00 op 0 0 0
# OS-PROC-GNU-NEXT: [10] .exclude PROGBITS 0000000000000000 000040 000000 00 E 0 0 0
# OS-PROC-GNU-NEXT: [11] .all.possible PROGBITS 0000000000000000 000040 000000 00 WAXMSILOGTCopx 0 0 0
diff --git a/llvm/test/tools/llvm-readobj/ELF/section-flags.test b/llvm/test/tools/llvm-readobj/ELF/section-flags.test
index 57b6f0d687edd..15b79c4146823 100644
--- a/llvm/test/tools/llvm-readobj/ELF/section-flags.test
+++ b/llvm/test/tools/llvm-readobj/ELF/section-flags.test
@@ -6,11 +6,12 @@
# LLVM: Name: allflags
# LLVM-NEXT: Type: SHT_PROGBITS
-# LLVM-NEXT: Flags [ (0x80000FF7)
+# LLVM-NEXT: Flags [ (0x80200FF7)
# LLVM-NEXT: SHF_ALLOC (0x2)
# LLVM-NEXT: SHF_COMPRESSED (0x800)
# LLVM-NEXT: SHF_EXCLUDE (0x80000000)
# LLVM-NEXT: SHF_EXECINSTR (0x4)
+# LLVM-NEXT: SHF_GNU_RETAIN (0x200000)
# LLVM-NEXT: SHF_GROUP (0x200)
# LLVM-NEXT: SHF_INFO_LINK (0x40)
# LLVM-NEXT: SHF_LINK_ORDER (0x80)
@@ -92,6 +93,14 @@
# LLVM-NEXT: SHF_COMPRESSED (0x800)
# LLVM-NEXT: ]
+## SHF_GNU_RETAIN is defined in the OS-specific range, but we treat it generic
+## and allow it to be used with OSABI values other than GNU and FREEBSD.
+# LLVM: Name: retain
+# LLVM-NEXT: Type: SHT_PROGBITS
+# LLVM-NEXT: Flags [ (0x200000)
+# LLVM-NEXT: SHF_GNU_RETAIN (0x200000)
+# LLVM-NEXT: ]
+
# LLVM: Name: exclude
# LLVM-NEXT: Type: SHT_PROGBITS
# LLVM-NEXT: Flags [ (0x80000000)
@@ -104,7 +113,7 @@
# LLVM-NEXT: ]
# GNU: [Nr] Name Type Address Off Size ES Flg Lk Inf Al
-# GNU: [ 1] allflags PROGBITS 0000000000000000 000040 000000 00 WAXMSILOGTCE 0 0 0
+# GNU: [ 1] allflags PROGBITS 0000000000000000 000040 000000 00 WAXMSILOGTCRE 0 0 0
# GNU: [ 2] noflags PROGBITS 0000000000000000 000040 000000 00 0 0 0
# GNU: [ 3] write PROGBITS 0000000000000000 000040 000000 00 W 0 0 0
# GNU: [ 4] alloc PROGBITS 0000000000000000 000040 000000 00 A 0 0 0
@@ -117,8 +126,9 @@
# GNU: [11] group PROGBITS 0000000000000000 000040 000000 00 G 0 0 0
# GNU: [12] tls PROGBITS 0000000000000000 000040 000000 00 T 0 0 0
# GNU: [13] compressed PROGBITS 0000000000000000 000040 000000 00 C 0 0 0
-# GNU: [14] exclude PROGBITS 0000000000000000 000040 000000 00 E 0 0 0
-# GNU: [15] unknown PROGBITS 0000000000000000 000040 000000 00 x 0 0 0
+# GNU: [14] retain PROGBITS 0000000000000000 000040 000000 00 R 0 0 0
+# GNU: [15] exclude PROGBITS 0000000000000000 000040 000000 00 E 0 0 0
+# GNU: [16] unknown PROGBITS 0000000000000000 000040 000000 00 x 0 0 0
--- !ELF
FileHeader:
@@ -131,7 +141,7 @@ Sections:
Type: SHT_PROGBITS
Flags: [ SHF_WRITE, SHF_ALLOC, SHF_EXECINSTR, SHF_MERGE,
SHF_STRINGS, SHF_INFO_LINK, SHF_LINK_ORDER, SHF_OS_NONCONFORMING,
- SHF_GROUP, SHF_TLS, SHF_COMPRESSED, SHF_EXCLUDE ]
+ SHF_GROUP, SHF_TLS, SHF_COMPRESSED, SHF_GNU_RETAIN, SHF_EXCLUDE ]
- Name: noflags
Type: SHT_PROGBITS
Flags: [ ]
@@ -168,6 +178,9 @@ Sections:
- Name: compressed
Type: SHT_PROGBITS
Flags: [ SHF_COMPRESSED ]
+ - Name: retain
+ Type: SHT_PROGBITS
+ Flags: [ SHF_GNU_RETAIN ]
- Name: exclude
Type: SHT_PROGBITS
Flags: [ SHF_EXCLUDE ]
diff --git a/llvm/tools/llvm-readobj/ELFDumper.cpp b/llvm/tools/llvm-readobj/ELFDumper.cpp
index 4f6e984527e9a..74994ca912e1c 100644
--- a/llvm/tools/llvm-readobj/ELFDumper.cpp
+++ b/llvm/tools/llvm-readobj/ELFDumper.cpp
@@ -1201,6 +1201,7 @@ static const EnumEntry<unsigned> ElfSectionFlags[] = {
ENUM_ENT(SHF_GROUP, "G"),
ENUM_ENT(SHF_TLS, "T"),
ENUM_ENT(SHF_COMPRESSED, "C"),
+ ENUM_ENT(SHF_GNU_RETAIN, "R"),
ENUM_ENT(SHF_EXCLUDE, "E"),
};
@@ -3483,15 +3484,14 @@ static void printSectionDescription(formatted_raw_ostream &OS,
OS << " L (link order), O (extra OS processing required), G (group), T "
"(TLS),\n";
OS << " C (compressed), x (unknown), o (OS specific), E (exclude),\n";
+ OS << " R (retain)";
if (EMachine == EM_X86_64)
- OS << " l (large), ";
+ OS << ", l (large)";
else if (EMachine == EM_ARM)
- OS << " y (purecode), ";
- else
- OS << " ";
+ OS << ", y (purecode)";
- OS << "p (processor specific)\n";
+ OS << ", p (processor specific)\n";
}
template <class ELFT> void GNUELFDumper<ELFT>::printSectionHeaders() {
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