[llvm] [llvm-objcopy] Let --change-section-lma change segments wth filesz=0,… (PR #127724)

Jonathon Penix via llvm-commits llvm-commits at lists.llvm.org
Wed Feb 26 11:07:10 PST 2025


https://github.com/jonathonpenix updated https://github.com/llvm/llvm-project/pull/127724

>From 5e39ac8c25d32593474bb7309f2c8038b4ba625a Mon Sep 17 00:00:00 2001
From: Jonathon Penix <jpenix at quicinc.com>
Date: Tue, 18 Feb 2025 15:15:47 -0800
Subject: [PATCH 1/3] [llvm-objcopy] Let --change-section-lma change segments
 wth filesz=0, memsz>0

Currently, segments with a file size of 0 are ignored for the purposes of
--change-section-lma, regardless of their memory size. It seems reasonable
to me to modify such segments given that we're changing the LMA for all
sections and these LMAs may be used during loading. GNU objcopy also seems
to adjust such segments.

Fixes #124680
---
 llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp             |  2 +-
 .../llvm-objcopy/ELF/change-section-lma.test    | 17 +++++++++++++----
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
index 9c78f7433ad33..20a8e67625cac 100644
--- a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
+++ b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
@@ -824,7 +824,7 @@ static Error handleArgs(const CommonConfig &Config, const ELFConfig &ELFConfig,
 
   if (Config.ChangeSectionLMAValAll != 0) {
     for (Segment &Seg : Obj.segments()) {
-      if (Seg.FileSize > 0) {
+      if (Seg.FileSize > 0 || Seg.MemSize > 0) {
         if (Config.ChangeSectionLMAValAll > 0 &&
             Seg.PAddr > std::numeric_limits<uint64_t>::max() -
                             Config.ChangeSectionLMAValAll) {
diff --git a/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test b/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test
index c1cd1eb46d949..00a9e6de8d4a8 100644
--- a/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test
+++ b/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test
@@ -14,16 +14,18 @@
 
 # CHECK-PLUS-PROGRAMS:  Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz
 # CHECK-PLUS-PROGRAMS:  PHDR           0x000002 0x0000000000001102 0x0000000000001122 0x000038 0x000000
-# CHECK-PLUS-PROGRAMS:  LOAD           0x000000 0x0000000000001100 0x0000000000001120 0x000258 0x000258
-# CHECK-PLUS-PROGRAMS:  LOAD           0x000258 0xffffffff00005100 0xffffffff00006120 0x000100 0x000100
+# CHECK-PLUS-PROGRAMS:  LOAD           0x000000 0x0000000000001100 0x0000000000001120 0x000290 0x000290
+# CHECK-PLUS-PROGRAMS:  LOAD           0x000290 0xffffffff00005100 0xffffffff00006120 0x000100 0x000100
 # CHECK-PLUS-PROGRAMS:  NOTE           0x000358 0x0000000000001200 0x0000000000001220 0x000010 0x000000
 # CHECK-PLUS-PROGRAMS:  NOTE           0x000368 0x0000000000000000 0x0000000000000000 0x000000 0x000000
+# CHECK-PLUS-PROGRAMS:  LOAD           0x000390 0x0000000000001300 0x0000000000001320 0x000000 0x000010
 
 # CHECK-MINUS-PROGRAMS:  PHDR           0x000002 0x0000000000001102 0x00000000000010d2 0x000038 0x000000
-# CHECK-MINUS-PROGRAMS:  LOAD           0x000000 0x0000000000001100 0x00000000000010d0 0x000258 0x000258
-# CHECK-MINUS-PROGRAMS:  LOAD           0x000258 0xffffffff00005100 0xffffffff000060d0 0x000100 0x000100
+# CHECK-MINUS-PROGRAMS:  LOAD           0x000000 0x0000000000001100 0x00000000000010d0 0x000290 0x000290
+# CHECK-MINUS-PROGRAMS:  LOAD           0x000290 0xffffffff00005100 0xffffffff000060d0 0x000100 0x000100
 # CHECK-MINUS-PROGRAMS:  NOTE           0x000358 0x0000000000001200 0x00000000000011d0 0x000010 0x000000
 # CHECK-MINUS-PROGRAMS:  NOTE           0x000368 0x0000000000000000 0x0000000000000000 0x000000 0x000000
+# CHECK-MINUS-PROGRAMS:  LOAD           0x000390 0x0000000000001300 0x00000000000012d0 0x000000 0x000010
 
 # CHECK-PLUS-SECTIONS:      [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
 # CHECK-PLUS-SECTIONS:           .text1
@@ -55,6 +57,9 @@ Sections:
   - Name:          .text2
     Type:          SHT_PROGBITS
     Size:          0x100
+  - Name:          .bss1
+    Type:          SHT_NOBITS
+    Size:          0x10
 ProgramHeaders:
   - Type:          PT_PHDR
     FileSize:      0x38
@@ -77,3 +82,7 @@ ProgramHeaders:
   - Type:          PT_NOTE
     FileSize:      0x0
     Offset:        0x368
+  - Type:          PT_LOAD
+    VAddr:         0x1300
+    FirstSec:      .bss1
+    LastSec:       .bss1

>From 3d232518bc408e6d697a6b7ce115b9e578e793ce Mon Sep 17 00:00:00 2001
From: Jonathon Penix <jpenix at quicinc.com>
Date: Mon, 24 Feb 2025 15:42:47 -0800
Subject: [PATCH 2/3] fixup! [llvm-objcopy] Let --change-section-lma change
 segments wth filesz=0, memsz>0

---
 llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp           |  2 +-
 .../llvm-objcopy/ELF/change-section-lma.test  | 30 ++++++++++++-------
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
index 20a8e67625cac..1a31bfa2e0db3 100644
--- a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
+++ b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
@@ -824,7 +824,7 @@ static Error handleArgs(const CommonConfig &Config, const ELFConfig &ELFConfig,
 
   if (Config.ChangeSectionLMAValAll != 0) {
     for (Segment &Seg : Obj.segments()) {
-      if (Seg.FileSize > 0 || Seg.MemSize > 0) {
+      if (Seg.MemSize > 0) {
         if (Config.ChangeSectionLMAValAll > 0 &&
             Seg.PAddr > std::numeric_limits<uint64_t>::max() -
                             Config.ChangeSectionLMAValAll) {
diff --git a/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test b/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test
index 00a9e6de8d4a8..6d2bc28fbdb16 100644
--- a/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test
+++ b/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test
@@ -13,19 +13,21 @@
 # RUN: not llvm-objcopy --change-section-lma *+0x100000000 %t  2>&1 | FileCheck %s --check-prefix=ERR-OVERFLOW
 
 # CHECK-PLUS-PROGRAMS:  Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz
-# CHECK-PLUS-PROGRAMS:  PHDR           0x000002 0x0000000000001102 0x0000000000001122 0x000038 0x000000
-# CHECK-PLUS-PROGRAMS:  LOAD           0x000000 0x0000000000001100 0x0000000000001120 0x000290 0x000290
-# CHECK-PLUS-PROGRAMS:  LOAD           0x000290 0xffffffff00005100 0xffffffff00006120 0x000100 0x000100
-# CHECK-PLUS-PROGRAMS:  NOTE           0x000358 0x0000000000001200 0x0000000000001220 0x000010 0x000000
+# CHECK-PLUS-PROGRAMS:  PHDR           0x000002 0x0000000000001102 0x0000000000001122 0x000038 0x000038
+# CHECK-PLUS-PROGRAMS:  LOAD           0x000000 0x0000000000001100 0x0000000000001120 0x0002c8 0x0002c8
+# CHECK-PLUS-PROGRAMS:  LOAD           0x0002c8 0xffffffff00005100 0xffffffff00006120 0x000100 0x000100
+# CHECK-PLUS-PROGRAMS:  NOTE           0x000358 0x0000000000001200 0x0000000000001220 0x000010 0x000010
 # CHECK-PLUS-PROGRAMS:  NOTE           0x000368 0x0000000000000000 0x0000000000000000 0x000000 0x000000
-# CHECK-PLUS-PROGRAMS:  LOAD           0x000390 0x0000000000001300 0x0000000000001320 0x000000 0x000010
+# CHECK-PLUS-PROGRAMS:  LOAD           0x0003c8 0x0000000000001300 0x0000000000001320 0x000000 0x000010
+# CHECK-PLUS-PROGRAMS:  NOTE           0x000378 0x0000000000001400 0x0000000000001400 0x000010 0x000000
 
-# CHECK-MINUS-PROGRAMS:  PHDR           0x000002 0x0000000000001102 0x00000000000010d2 0x000038 0x000000
-# CHECK-MINUS-PROGRAMS:  LOAD           0x000000 0x0000000000001100 0x00000000000010d0 0x000290 0x000290
-# CHECK-MINUS-PROGRAMS:  LOAD           0x000290 0xffffffff00005100 0xffffffff000060d0 0x000100 0x000100
-# CHECK-MINUS-PROGRAMS:  NOTE           0x000358 0x0000000000001200 0x00000000000011d0 0x000010 0x000000
+# CHECK-MINUS-PROGRAMS:  PHDR           0x000002 0x0000000000001102 0x00000000000010d2 0x000038 0x000038
+# CHECK-MINUS-PROGRAMS:  LOAD           0x000000 0x0000000000001100 0x00000000000010d0 0x0002c8 0x0002c8
+# CHECK-MINUS-PROGRAMS:  LOAD           0x0002c8 0xffffffff00005100 0xffffffff000060d0 0x000100 0x000100
+# CHECK-MINUS-PROGRAMS:  NOTE           0x000358 0x0000000000001200 0x00000000000011d0 0x000010 0x000010
 # CHECK-MINUS-PROGRAMS:  NOTE           0x000368 0x0000000000000000 0x0000000000000000 0x000000 0x000000
-# CHECK-MINUS-PROGRAMS:  LOAD           0x000390 0x0000000000001300 0x00000000000012d0 0x000000 0x000010
+# CHECK-MINUS-PROGRAMS:  LOAD           0x0003c8 0x0000000000001300 0x00000000000012d0 0x000000 0x000010
+# CHECK-MINUS-PROGRAMS:  NOTE           0x000378 0x0000000000001400 0x0000000000001400 0x000010 0x000000
 
 # CHECK-PLUS-SECTIONS:      [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
 # CHECK-PLUS-SECTIONS:           .text1
@@ -63,6 +65,7 @@ Sections:
 ProgramHeaders:
   - Type:          PT_PHDR
     FileSize:      0x38
+    MemSize:       0x38
     Offset:        0x2
     VAddr:         0x1102
   - Type:          PT_LOAD
@@ -77,12 +80,19 @@ ProgramHeaders:
     LastSec:       .text2
   - Type:          PT_NOTE
     FileSize:      0x10
+    MemSize:       0x10
     VAddr:         0x1200
     Offset:        0x358
   - Type:          PT_NOTE
     FileSize:      0x0
+    MemSize:       0x0
     Offset:        0x368
   - Type:          PT_LOAD
     VAddr:         0x1300
     FirstSec:      .bss1
     LastSec:       .bss1
+  - Type:          PT_NOTE
+    FileSize:      0x10
+    MemSize:       0x0
+    VAddr:         0x1400
+    Offset:        0x378

>From 91ebc90de6aab8152f229466d573c1768a4b2840 Mon Sep 17 00:00:00 2001
From: Jonathon Penix <jpenix at quicinc.com>
Date: Wed, 26 Feb 2025 11:04:38 -0800
Subject: [PATCH 3/3] fixup! [llvm-objcopy] Let --change-section-lma change
 segments wth filesz=0, memsz>0

---
 llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test b/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test
index 6d2bc28fbdb16..ee4648dc7aa81 100644
--- a/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test
+++ b/llvm/test/tools/llvm-objcopy/ELF/change-section-lma.test
@@ -19,7 +19,7 @@
 # CHECK-PLUS-PROGRAMS:  NOTE           0x000358 0x0000000000001200 0x0000000000001220 0x000010 0x000010
 # CHECK-PLUS-PROGRAMS:  NOTE           0x000368 0x0000000000000000 0x0000000000000000 0x000000 0x000000
 # CHECK-PLUS-PROGRAMS:  LOAD           0x0003c8 0x0000000000001300 0x0000000000001320 0x000000 0x000010
-# CHECK-PLUS-PROGRAMS:  NOTE           0x000378 0x0000000000001400 0x0000000000001400 0x000010 0x000000
+# CHECK-PLUS-PROGRAMS:  NOTE           0x000378 0x0000000000000000 0x0000000000000000 0x000010 0x000000
 
 # CHECK-MINUS-PROGRAMS:  PHDR           0x000002 0x0000000000001102 0x00000000000010d2 0x000038 0x000038
 # CHECK-MINUS-PROGRAMS:  LOAD           0x000000 0x0000000000001100 0x00000000000010d0 0x0002c8 0x0002c8
@@ -27,7 +27,7 @@
 # CHECK-MINUS-PROGRAMS:  NOTE           0x000358 0x0000000000001200 0x00000000000011d0 0x000010 0x000010
 # CHECK-MINUS-PROGRAMS:  NOTE           0x000368 0x0000000000000000 0x0000000000000000 0x000000 0x000000
 # CHECK-MINUS-PROGRAMS:  LOAD           0x0003c8 0x0000000000001300 0x00000000000012d0 0x000000 0x000010
-# CHECK-MINUS-PROGRAMS:  NOTE           0x000378 0x0000000000001400 0x0000000000001400 0x000010 0x000000
+# CHECK-MINUS-PROGRAMS:  NOTE           0x000378 0x0000000000000000 0x0000000000000000 0x000010 0x000000
 
 # CHECK-PLUS-SECTIONS:      [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
 # CHECK-PLUS-SECTIONS:           .text1
@@ -94,5 +94,4 @@ ProgramHeaders:
   - Type:          PT_NOTE
     FileSize:      0x10
     MemSize:       0x0
-    VAddr:         0x1400
     Offset:        0x378



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