[llvm] 93345e8 - [llvm-objcopy] -O binary: consider SHT_NOBITS sections to be empty
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Mon Feb 1 15:01:34 PST 2021
Author: Patrick Oppenlander
Date: 2021-02-01T15:01:25-08:00
New Revision: 93345e825a0733f6a67898f6d6d156ff56db80e7
URL: https://github.com/llvm/llvm-project/commit/93345e825a0733f6a67898f6d6d156ff56db80e7
DIFF: https://github.com/llvm/llvm-project/commit/93345e825a0733f6a67898f6d6d156ff56db80e7.diff
LOG: [llvm-objcopy] -O binary: consider SHT_NOBITS sections to be empty
This is consistent with BFD objcopy.
Previously llvm objcopy would allocate space for SHT_NOBITS sections
often resulting in enormous binary files.
New test case (binary-paddr.test %t6).
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D95569
Added:
Modified:
llvm/test/tools/llvm-objcopy/ELF/binary-paddr.test
llvm/tools/llvm-objcopy/ELF/Object.cpp
Removed:
################################################################################
diff --git a/llvm/test/tools/llvm-objcopy/ELF/binary-paddr.test b/llvm/test/tools/llvm-objcopy/ELF/binary-paddr.test
index bee80b28b532..023414429a3c 100644
--- a/llvm/test/tools/llvm-objcopy/ELF/binary-paddr.test
+++ b/llvm/test/tools/llvm-objcopy/ELF/binary-paddr.test
@@ -183,3 +183,34 @@ Sections:
- Name: .data
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC, SHF_WRITE ]
+
+## NOBITS sections should not appear in output.
+# RUN: yaml2obj --docnum=6 %s -o %t6
+# RUN: llvm-objcopy -O binary %t6 %t6.out
+# RUN: od -A x -t x2 %t6.out | FileCheck %s --check-prefix=SKIPNOBITS --ignore-case
+
+# SKIPNOBITS: 000000 c3c3 c3c3
+# SKIPNOBITS-NEXT: 000004
+
+--- !ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_EXEC
+ Machine: EM_X86_64
+Sections:
+ - Name: .bss
+ Type: SHT_NOBITS
+ Flags: [ SHF_ALLOC ]
+ Address: 0x1000
+ AddressAlign: 0x1000
+ Size: 0x123
+ - Name: gap
+ Type: Fill
+ Size: 0xffd
+ - Name: .text
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+ Address: 0x4000
+ AddressAlign: 0x1000
+ Content: "c3c3c3c3"
diff --git a/llvm/tools/llvm-objcopy/ELF/Object.cpp b/llvm/tools/llvm-objcopy/ELF/Object.cpp
index 0ff82f951b62..7faf415644fb 100644
--- a/llvm/tools/llvm-objcopy/ELF/Object.cpp
+++ b/llvm/tools/llvm-objcopy/ELF/Object.cpp
@@ -2553,7 +2553,7 @@ Error BinaryWriter::finalize() {
if (Sec.ParentSegment != nullptr)
Sec.Addr =
Sec.Offset - Sec.ParentSegment->Offset + Sec.ParentSegment->PAddr;
- if (Sec.Size > 0)
+ if (Sec.Type != SHT_NOBITS && Sec.Size > 0)
MinAddr = std::min(MinAddr, Sec.Addr);
}
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