[llvm-branch-commits] [lld] r371196 - Merging r369828:
Hans Wennborg via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Fri Sep 6 04:18:45 PDT 2019
Author: hans
Date: Fri Sep 6 04:18:45 2019
New Revision: 371196
URL: http://llvm.org/viewvc/llvm-project?rev=371196&view=rev
Log:
Merging r369828:
------------------------------------------------------------------------
r369828 | maskray | 2019-08-24 02:41:15 +0200 (Sat, 24 Aug 2019) | 18 lines
[ELF] Align the first section of a PT_LOAD even if its type is SHT_NOBITS
Reported at https://reviews.llvm.org/D64930#1642223
If the only section of a PT_LOAD is a SHT_NOBITS section (e.g. .bss), we
may not align its sh_offset. p_offset of the PT_LOAD will be set to
sh_offset, and we will get p_offset!=p_vaddr (mod p_align). If such
executable is mapped by the Linux kernel, it will segfault.
After D64906, this may happen the non-linker script case.
The linker script case has had this issue for a long time.
This was fixed by rL321657 (but the test linkerscript/nobits-offset.s
failed to test a SHT_NOBITS section), but broken by rL345154.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D66658
------------------------------------------------------------------------
Added:
lld/branches/release_90/test/ELF/nobits-offset.s
- copied, changed from r369828, lld/trunk/test/ELF/nobits-offset.s
Modified:
lld/branches/release_90/ (props changed)
lld/branches/release_90/ELF/Writer.cpp
lld/branches/release_90/test/ELF/basic-ppc64.s
lld/branches/release_90/test/ELF/linkerscript/nobits-offset.s
lld/branches/release_90/test/ELF/relocation-copy-align-common.s
Propchange: lld/branches/release_90/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Fri Sep 6 04:18:45 2019
@@ -1 +1 @@
-/lld/trunk:366445,366447,366500,366504,366573,366780,366784,366836,367836-367837,368041,368078,368145,368964,369184,369445,369694
+/lld/trunk:366445,366447,366500,366504,366573,366780,366784,366836,367836-367837,368041,368078,368145,368964,369184,369445,369694,369828
Modified: lld/branches/release_90/ELF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/branches/release_90/ELF/Writer.cpp?rev=371196&r1=371195&r2=371196&view=diff
==============================================================================
--- lld/branches/release_90/ELF/Writer.cpp (original)
+++ lld/branches/release_90/ELF/Writer.cpp Fri Sep 6 04:18:45 2019
@@ -2230,25 +2230,26 @@ template <class ELFT> void Writer<ELFT>:
// same with its virtual address modulo the page size, so that the loader can
// load executables without any address adjustment.
static uint64_t computeFileOffset(OutputSection *os, uint64_t off) {
- // File offsets are not significant for .bss sections. By convention, we keep
- // section offsets monotonically increasing rather than setting to zero.
- if (os->type == SHT_NOBITS)
- return off;
-
- // If the section is not in a PT_LOAD, we just have to align it.
- if (!os->ptLoad)
- return alignTo(off, os->alignment);
-
// The first section in a PT_LOAD has to have congruent offset and address
// module the page size.
- OutputSection *first = os->ptLoad->firstSec;
- if (os == first) {
+ if (os->ptLoad && os->ptLoad->firstSec == os) {
uint64_t alignment = std::max<uint64_t>(os->alignment, config->maxPageSize);
return alignTo(off, alignment, os->addr);
}
+ // File offsets are not significant for .bss sections other than the first one
+ // in a PT_LOAD. By convention, we keep section offsets monotonically
+ // increasing rather than setting to zero.
+ if (os->type == SHT_NOBITS)
+ return off;
+
+ // If the section is not in a PT_LOAD, we just have to align it.
+ if (!os->ptLoad)
+ return alignTo(off, os->alignment);
+
// If two sections share the same PT_LOAD the file offset is calculated
// using this formula: Off2 = Off1 + (VA2 - VA1).
+ OutputSection *first = os->ptLoad->firstSec;
return first->offset + os->addr - first->addr;
}
Modified: lld/branches/release_90/test/ELF/basic-ppc64.s
URL: http://llvm.org/viewvc/llvm-project/lld/branches/release_90/test/ELF/basic-ppc64.s?rev=371196&r1=371195&r2=371196&view=diff
==============================================================================
--- lld/branches/release_90/test/ELF/basic-ppc64.s (original)
+++ lld/branches/release_90/test/ELF/basic-ppc64.s Fri Sep 6 04:18:45 2019
@@ -35,7 +35,7 @@
// CHECK-NEXT: Version: 1
// CHECK-NEXT: Entry: 0x10000
// CHECK-NEXT: ProgramHeaderOffset: 0x40
-// CHECK-NEXT: SectionHeaderOffset: 0x200F8
+// CHECK-NEXT: SectionHeaderOffset: 0x30098
// CHECK-NEXT: Flags [ (0x2)
// CHECK-NEXT: 0x2
// CHECK-NEXT: ]
@@ -178,7 +178,7 @@
// CHECK-NEXT: SHF_WRITE (0x1)
// CHECK-NEXT: ]
// CHECK-NEXT: Address: 0x30000
-// CHECK-NEXT: Offset: 0x20060
+// CHECK-NEXT: Offset: 0x30000
// CHECK-NEXT: Size: 0
// CHECK-NEXT: Link: 0
// CHECK-NEXT: Info: 0
@@ -194,7 +194,7 @@
// CHECK-NEXT: SHF_STRINGS (0x20)
// CHECK-NEXT: ]
// CHECK-NEXT: Address: 0x0
-// CHECK-NEXT: Offset: 0x20060
+// CHECK-NEXT: Offset: 0x30000
// CHECK-NEXT: Size: 8
// CHECK-NEXT: Link: 0
// CHECK-NEXT: Info: 0
@@ -211,7 +211,7 @@
// CHECK-NEXT: Flags [ (0x0)
// CHECK-NEXT: ]
// CHECK-NEXT: Address: 0x0
-// CHECK-NEXT: Offset: 0x20068
+// CHECK-NEXT: Offset: 0x30008
// CHECK-NEXT: Size: 48
// CHECK-NEXT: Link: 10
// CHECK-NEXT: Info: 2
@@ -233,7 +233,7 @@
// CHECK-NEXT: Flags [ (0x0)
// CHECK-NEXT: ]
// CHECK-NEXT: Address: 0x0
-// CHECK-NEXT: Offset: 0x20098
+// CHECK-NEXT: Offset: 0x30038
// CHECK-NEXT: Size: 84
// CHECK-NEXT: Link: 0
// CHECK-NEXT: Info: 0
@@ -255,7 +255,7 @@
// CHECK-NEXT: Flags [ (0x0)
// CHECK-NEXT: ]
// CHECK-NEXT: Address: 0x0
-// CHECK-NEXT: Offset: 0x200EC
+// CHECK-NEXT: Offset: 0x3008C
// CHECK-NEXT: Size: 10
// CHECK-NEXT: Link: 0
// CHECK-NEXT: Info: 0
Modified: lld/branches/release_90/test/ELF/linkerscript/nobits-offset.s
URL: http://llvm.org/viewvc/llvm-project/lld/branches/release_90/test/ELF/linkerscript/nobits-offset.s?rev=371196&r1=371195&r2=371196&view=diff
==============================================================================
--- lld/branches/release_90/test/ELF/linkerscript/nobits-offset.s (original)
+++ lld/branches/release_90/test/ELF/linkerscript/nobits-offset.s Fri Sep 6 04:18:45 2019
@@ -2,17 +2,24 @@
# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
# RUN: echo "SECTIONS { \
# RUN: .sec1 (NOLOAD) : { . += 1; } \
-# RUN: .text : { *(.text) } \
+# RUN: .bss : { *(.bss) } \
# RUN: };" > %t.script
# RUN: ld.lld %t.o -T %t.script -o %t
-# RUN: llvm-readelf --sections %t | FileCheck %s
+# RUN: llvm-readelf -S -l %t | FileCheck %s
-# We used to misalign section offsets if the first section in a
-# PT_LOAD was SHT_NOBITS.
+## If a SHT_NOBITS section is the only section of a PT_LOAD segment,
+## p_offset will be set to the sh_offset field of the section. Check we align
+## sh_offset to sh_addr modulo max-page-size, so that p_vaddr=p_offset (mod
+## p_align).
-# CHECK: [ 2] .text PROGBITS 0000000000000010 001010 000010 00 AX 0 0 16
+# CHECK: Name Type Address Off Size ES Flg Lk Inf Al
+# CHECK: .bss NOBITS 0000000000000400 001400 000001 00 WA 0 0 1024
-.global _start
-_start:
- nop
-.p2align 4
+# CHECK: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
+# CHECK: LOAD 0x001400 0x0000000000000400 0x0000000000000400 0x000000 0x000001 RW 0x1000
+
+# CHECK: 00 .bss
+
+.bss
+.p2align 10
+.byte 0
Copied: lld/branches/release_90/test/ELF/nobits-offset.s (from r369828, lld/trunk/test/ELF/nobits-offset.s)
URL: http://llvm.org/viewvc/llvm-project/lld/branches/release_90/test/ELF/nobits-offset.s?p2=lld/branches/release_90/test/ELF/nobits-offset.s&p1=lld/trunk/test/ELF/nobits-offset.s&r1=369828&r2=371196&rev=371196&view=diff
==============================================================================
--- lld/trunk/test/ELF/nobits-offset.s (original)
+++ lld/branches/release_90/test/ELF/nobits-offset.s Fri Sep 6 04:18:45 2019
@@ -9,10 +9,10 @@
## p_align).
# CHECK: Name Type Address Off Size ES Flg Lk Inf Al
-# CHECK: .bss NOBITS 0000000000221000 001000 000001 00 WA 0 0 4096
+# CHECK: .bss NOBITS 0000000000210000 010000 000001 00 WA 0 0 4096
# CHECK: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
-# CHECK: LOAD 0x001000 0x0000000000221000 0x0000000000221000 0x000000 0x000001 RW 0x10000
+# CHECK: LOAD 0x010000 0x0000000000210000 0x0000000000210000 0x000000 0x000001 RW 0x10000
# CHECK: 02 .bss
Modified: lld/branches/release_90/test/ELF/relocation-copy-align-common.s
URL: http://llvm.org/viewvc/llvm-project/lld/branches/release_90/test/ELF/relocation-copy-align-common.s?rev=371196&r1=371195&r2=371196&view=diff
==============================================================================
--- lld/branches/release_90/test/ELF/relocation-copy-align-common.s (original)
+++ lld/branches/release_90/test/ELF/relocation-copy-align-common.s Fri Sep 6 04:18:45 2019
@@ -15,7 +15,7 @@
# CHECK-NEXT: SHF_WRITE
# CHECK-NEXT: ]
# CHECK-NEXT: Address: 0x203000
-# CHECK-NEXT: Offset: 0x20B0
+# CHECK-NEXT: Offset: 0x3000
# CHECK-NEXT: Size: 16
# CHECK-NEXT: Link: 0
# CHECK-NEXT: Info: 0
More information about the llvm-branch-commits
mailing list