[lld] r371398 - [ELF] nmagic or omagic: don't allocate PT_PHDR or PF_R PT_LOAD for the !hasPhdrsCommands case
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Mon Sep 9 06:08:52 PDT 2019
Author: maskray
Date: Mon Sep 9 06:08:51 2019
New Revision: 371398
URL: http://llvm.org/viewvc/llvm-project?rev=371398&view=rev
Log:
[ELF] nmagic or omagic: don't allocate PT_PHDR or PF_R PT_LOAD for the !hasPhdrsCommands case
```
part.phdrs = script->hasPhdrsCommands() ? script->createPhdrs() : createPhdrs(part);
```
createPhdrs() allocates a PT_PHDR and a PF_R PT_LOAD, which will be
deleted later in LinkerScript::allocateHeaders, but leave a gap between
the program headers and the first section. Don't allocate the segments
to avoid the gap. PT_INTERP is likely not needed as well.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D67324
Modified:
lld/trunk/ELF/Writer.cpp
lld/trunk/test/ELF/magic-page-combo-warn.s
lld/trunk/test/ELF/nmagic.s
lld/trunk/test/ELF/relro-omagic.s
lld/trunk/test/ELF/segments.s
Modified: lld/trunk/ELF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=371398&r1=371397&r2=371398&view=diff
==============================================================================
--- lld/trunk/ELF/Writer.cpp (original)
+++ lld/trunk/ELF/Writer.cpp Mon Sep 9 06:08:51 2019
@@ -2030,27 +2030,32 @@ std::vector<PhdrEntry *> Writer<ELFT>::c
unsigned partNo = part.getNumber();
bool isMain = partNo == 1;
- // The first phdr entry is PT_PHDR which describes the program header itself.
- if (isMain)
- addHdr(PT_PHDR, PF_R)->add(Out::programHeaders);
- else
- addHdr(PT_PHDR, PF_R)->add(part.programHeaders->getParent());
-
- // PT_INTERP must be the second entry if exists.
- if (OutputSection *cmd = findSection(".interp", partNo))
- addHdr(PT_INTERP, cmd->getPhdrFlags())->add(cmd);
-
// Add the first PT_LOAD segment for regular output sections.
uint64_t flags = computeFlags(PF_R);
PhdrEntry *load = nullptr;
- // Add the headers. We will remove them if they don't fit.
- // In the other partitions the headers are ordinary sections, so they don't
- // need to be added here.
- if (isMain) {
- load = addHdr(PT_LOAD, flags);
- load->add(Out::elfHeader);
- load->add(Out::programHeaders);
+ // nmagic or omagic output does not have PT_PHDR, PT_INTERP, or the readonly
+ // PT_LOAD.
+ if (!config->nmagic && !config->omagic) {
+ // The first phdr entry is PT_PHDR which describes the program header
+ // itself.
+ if (isMain)
+ addHdr(PT_PHDR, PF_R)->add(Out::programHeaders);
+ else
+ addHdr(PT_PHDR, PF_R)->add(part.programHeaders->getParent());
+
+ // PT_INTERP must be the second entry if exists.
+ if (OutputSection *cmd = findSection(".interp", partNo))
+ addHdr(PT_INTERP, cmd->getPhdrFlags())->add(cmd);
+
+ // Add the headers. We will remove them if they don't fit.
+ // In the other partitions the headers are ordinary sections, so they don't
+ // need to be added here.
+ if (isMain) {
+ load = addHdr(PT_LOAD, flags);
+ load->add(Out::elfHeader);
+ load->add(Out::programHeaders);
+ }
}
// PT_GNU_RELRO includes all sections that should be marked as
Modified: lld/trunk/test/ELF/magic-page-combo-warn.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/magic-page-combo-warn.s?rev=371398&r1=371397&r2=371398&view=diff
==============================================================================
--- lld/trunk/test/ELF/magic-page-combo-warn.s (original)
+++ lld/trunk/test/ELF/magic-page-combo-warn.s Mon Sep 9 06:08:51 2019
@@ -13,7 +13,7 @@
# OMAGIC: ProgramHeader {
# OMAGIC: Type: PT_LOAD
-# OMAGIC-NEXT: Offset: 0xE8
+# OMAGIC-NEXT: Offset: 0xB0
# OMAGIC-NEXT: VirtualAddress:
# OMAGIC-NEXT: PhysicalAddress:
# OMAGIC-NEXT: FileSize:
@@ -23,7 +23,7 @@
# OMAGIC-NEXT: PF_W
# OMAGIC-NEXT: PF_X
# OMAGIC-NEXT: ]
-# OMAGIC-NEXT: Alignment: 8
+# OMAGIC-NEXT: Alignment: 4
# OMAGIC-NEXT: }
# OMAGIC-NEXT: ProgramHeader {
# OMAGIC-NEXT: Type: PT_GNU_STACK
@@ -35,7 +35,7 @@
# NMAGIC: ProgramHeader {
# NMAGIC-NEXT: Type: PT_LOAD
-# NMAGIC-NEXT: Offset: 0x158
+# NMAGIC-NEXT: Offset: 0x120
# NMAGIC-NEXT: VirtualAddress:
# NMAGIC-NEXT: PhysicalAddress:
# NMAGIC-NEXT: FileSize: 1
@@ -43,11 +43,11 @@
# NMAGIC-NEXT: Flags [
# NMAGIC-NEXT: PF_R
# NMAGIC-NEXT: ]
-# NMAGIC-NEXT: Alignment: 8
+# NMAGIC-NEXT: Alignment: 1
# NMAGIC-NEXT: }
# NMAGIC-NEXT: ProgramHeader {
# NMAGIC-NEXT: Type: PT_LOAD
-# NMAGIC-NEXT: Offset: 0x15C
+# NMAGIC-NEXT: Offset: 0x124
# NMAGIC-NEXT: VirtualAddress:
# NMAGIC-NEXT: PhysicalAddress:
# NMAGIC-NEXT: FileSize: 2
@@ -60,7 +60,7 @@
# NMAGIC-NEXT: }
# NMAGIC-NEXT: ProgramHeader {
# NMAGIC-NEXT: Type: PT_LOAD (0x1)
-# NMAGIC-NEXT: Offset: 0x15E
+# NMAGIC-NEXT: Offset: 0x126
# NMAGIC-NEXT: VirtualAddress:
# NMAGIC-NEXT: PhysicalAddress:
# NMAGIC-NEXT: FileSize: 1
Modified: lld/trunk/test/ELF/nmagic.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/nmagic.s?rev=371398&r1=371397&r2=371398&view=diff
==============================================================================
--- lld/trunk/test/ELF/nmagic.s (original)
+++ lld/trunk/test/ELF/nmagic.s Mon Sep 9 06:08:51 2019
@@ -6,12 +6,12 @@
# RUN: llvm-readelf --section-headers %t.exe | FileCheck %s
# CHECK: [ 0] NULL 00000000 000000 000000 00 0 0 0
-# CHECK: [ 1] .text PROGBITS 00000000 0000d4 000001 00 AX 0 0 4
-# CHECK: [ 2] .rodata PROGBITS 00000008 0000d8 000008 00 A 0 0 8
-# CHECK: [ 3] .comment PROGBITS 00000000 0000e0 000008 01 MS 0 0 1
-# CHECK: [ 4] .symtab SYMTAB 00000000 0000e8 000020 10 6 1 4
-# CHECK: [ 5] .shstrtab STRTAB 00000000 000108 000032 00 0 0 1
-# CHECK: [ 6] .strtab STRTAB 00000000 00013a 000008 00 0 0 1
+# CHECK: [ 1] .text PROGBITS 00000000 000094 000001 00 AX 0 0 4
+# CHECK: [ 2] .rodata PROGBITS 00000008 000098 000008 00 A 0 0 8
+# CHECK: [ 3] .comment PROGBITS 00000000 0000a0 000008 01 MS 0 0 1
+# CHECK: [ 4] .symtab SYMTAB 00000000 0000a8 000020 10 6 1 4
+# CHECK: [ 5] .shstrtab STRTAB 00000000 0000c8 000032 00 0 0 1
+# CHECK: [ 6] .strtab STRTAB 00000000 0000fa 000008 00 0 0 1
.globl _start
.text
Modified: lld/trunk/test/ELF/relro-omagic.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/relro-omagic.s?rev=371398&r1=371397&r2=371398&view=diff
==============================================================================
--- lld/trunk/test/ELF/relro-omagic.s (original)
+++ lld/trunk/test/ELF/relro-omagic.s Mon Sep 9 06:08:51 2019
@@ -9,18 +9,18 @@
# NORELRO: Sections:
# NORELRO-NEXT: Idx Name Size VMA Type
# NORELRO-NEXT: 0 00000000 0000000000000000
-# NORELRO-NEXT: 1 .dynsym 00000048 0000000000200120
-# NORELRO-NEXT: 2 .hash 00000020 0000000000200168
-# NORELRO-NEXT: 3 .dynstr 00000021 0000000000200188
-# NORELRO-NEXT: 4 .rela.dyn 00000018 00000000002001b0
-# NORELRO-NEXT: 5 .rela.plt 00000018 00000000002001c8
-# NORELRO-NEXT: 6 .text 0000000a 00000000002001e0 TEXT
-# NORELRO-NEXT: 7 .plt 00000020 00000000002001f0 TEXT
-# NORELRO-NEXT: 8 .data 00000008 0000000000200210 DATA
-# NORELRO-NEXT: 9 .foo 00000004 0000000000200218 DATA
-# NORELRO-NEXT: 10 .dynamic 000000f0 0000000000200220
-# NORELRO-NEXT: 11 .got 00000008 0000000000200310 DATA
-# NORELRO-NEXT: 12 .got.plt 00000020 0000000000200318 DATA
+# NORELRO-NEXT: 1 .dynsym 00000048 00000000002000e8
+# NORELRO-NEXT: 2 .hash 00000020 0000000000200130
+# NORELRO-NEXT: 3 .dynstr 00000021 0000000000200150
+# NORELRO-NEXT: 4 .rela.dyn 00000018 0000000000200178
+# NORELRO-NEXT: 5 .rela.plt 00000018 0000000000200190
+# NORELRO-NEXT: 6 .text 0000000a 00000000002001a8 TEXT
+# NORELRO-NEXT: 7 .plt 00000020 00000000002001c0 TEXT
+# NORELRO-NEXT: 8 .data 00000008 00000000002001e0 DATA
+# NORELRO-NEXT: 9 .foo 00000004 00000000002001e8 DATA
+# NORELRO-NEXT: 10 .dynamic 000000f0 00000000002001f0
+# NORELRO-NEXT: 11 .got 00000008 00000000002002e0 DATA
+# NORELRO-NEXT: 12 .got.plt 00000020 00000000002002e8 DATA
# NOPHDRS: ProgramHeaders [
# NOPHDRS-NOT: PT_GNU_RELRO
Modified: lld/trunk/test/ELF/segments.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/segments.s?rev=371398&r1=371397&r2=371398&view=diff
==============================================================================
--- lld/trunk/test/ELF/segments.s (original)
+++ lld/trunk/test/ELF/segments.s Mon Sep 9 06:08:51 2019
@@ -84,7 +84,7 @@
# OMAGIC: ProgramHeader {
# OMAGIC: Type: PT_LOAD
-# OMAGIC-NEXT: Offset: 0xE8
+# OMAGIC-NEXT: Offset: 0xB0
# OMAGIC-NEXT: VirtualAddress:
# OMAGIC-NEXT: PhysicalAddress:
# OMAGIC-NEXT: FileSize:
@@ -94,7 +94,7 @@
# OMAGIC-NEXT: PF_W
# OMAGIC-NEXT: PF_X
# OMAGIC-NEXT: ]
-# OMAGIC-NEXT: Alignment: 8
+# OMAGIC-NEXT: Alignment: 4
# OMAGIC-NEXT: }
# OMAGIC-NEXT: ProgramHeader {
# OMAGIC-NEXT: Type: PT_GNU_STACK
@@ -106,7 +106,7 @@
# NMAGIC: ProgramHeader {
# NMAGIC-NEXT: Type: PT_LOAD
-# NMAGIC-NEXT: Offset: 0x158
+# NMAGIC-NEXT: Offset: 0x120
# NMAGIC-NEXT: VirtualAddress:
# NMAGIC-NEXT: PhysicalAddress:
# NMAGIC-NEXT: FileSize: 1
@@ -114,11 +114,11 @@
# NMAGIC-NEXT: Flags [
# NMAGIC-NEXT: PF_R
# NMAGIC-NEXT: ]
-# NMAGIC-NEXT: Alignment: 8
+# NMAGIC-NEXT: Alignment: 1
# NMAGIC-NEXT: }
# NMAGIC-NEXT: ProgramHeader {
# NMAGIC-NEXT: Type: PT_LOAD
-# NMAGIC-NEXT: Offset: 0x15C
+# NMAGIC-NEXT: Offset: 0x124
# NMAGIC-NEXT: VirtualAddress:
# NMAGIC-NEXT: PhysicalAddress:
# NMAGIC-NEXT: FileSize: 2
@@ -131,7 +131,7 @@
# NMAGIC-NEXT: }
# NMAGIC-NEXT: ProgramHeader {
# NMAGIC-NEXT: Type: PT_LOAD (0x1)
-# NMAGIC-NEXT: Offset: 0x15E
+# NMAGIC-NEXT: Offset: 0x126
# NMAGIC-NEXT: VirtualAddress:
# NMAGIC-NEXT: PhysicalAddress:
# NMAGIC-NEXT: FileSize: 1
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