[llvm-objcopy] Add --set-section-alignment

Fixes PR43181. This option was recently added to GNU objcopy (binutils PR24942). `llvm-objcopy -I binary -O elf64-x86-64 --set-section-alignment .data=8` can set the alignment of .data. Reviewed By: grimar, jhenderson, rupprecht Differential Revision: https://reviews.llvm.org/D67656 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@373461 91177308-0d34-0410-b5e6-96231b3b80d8
ROCm · Oct 2, 2019 · 72b55d4 · 72b55d4
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diff --git a/docs/CommandGuide/llvm-objcopy.rst b/docs/CommandGuide/llvm-objcopy.rst
@@ -82,6 +82,11 @@ multiple file formats.
  Remove the specified section from the output. Can be specified multiple times
  to remove multiple sections simultaneously.
 
+.. option:: --set-section-alignment <section>=<align>
+
+ Set the alignment of section ``<section>`` to `<align>``. Can be specified
+ multiple times to update multiple sections.
+
 .. option:: --strip-all-gnu
 
  Remove all symbols, debug sections and relocations from the output. This option

diff --git a/test/tools/llvm-objcopy/ELF/binary-input.test b/test/tools/llvm-objcopy/ELF/binary-input.test
@@ -110,3 +110,11 @@
 # CHECK-NEXT:     Section: Absolute
 # CHECK-NEXT:   }
 # CHECK-NEXT: ]
+
+## The alignment can be changed by --set-section-alignment.
+# RUN: llvm-objcopy -I binary -O elf64-x86-64 --set-section-alignment .data=8 %t.x-txt %t2.o
+# RUN: llvm-readobj --sections %t2.o | FileCheck --check-prefix=ALIGN %s
+
+# ALIGN:      Name: .data
+# ALIGN:      AddressAlignment:
+# ALIGN-SAME:                   8{{$}}
diff --git a/test/tools/llvm-objcopy/ELF/set-section-alignment.test b/test/tools/llvm-objcopy/ELF/set-section-alignment.test
@@ -0,0 +1,54 @@
+# RUN: yaml2obj %s -o %t
+
+# RUN: llvm-objcopy --set-section-alignment .foo=4 --set-section-alignment .bar=0x5 \
+# RUN:   --set-section-alignment .baz=0 %t %t.2
+# RUN: llvm-readobj --sections %t.2 | FileCheck --check-prefix=CHECK %s
+
+# CHECK:      Name: .foo
+# CHECK:      AddressAlignment:
+# CHECK-SAME:                   4{{$}}
+# CHECK:      Name: .bar
+# CHECK:      AddressAlignment:
+# CHECK-SAME:                   5{{$}}
+# CHECK:      Name: .baz
+# CHECK:      AddressAlignment:
+# CHECK-SAME:                   0{{$}}
+
+## If a section is specified multiple times, the last wins.
+# RUN: llvm-objcopy --set-section-alignment .foo=4 --set-section-alignment=.foo=7 %t %t.3
+# RUN: llvm-readobj --sections %t.3 | FileCheck --check-prefix=MULTI %s
+
+# MULTI:      Name: .foo
+# MULTI:      AddressAlignment:
+# MULTI-SAME:                   7{{$}}
+
+## Ignore the option if the section does not exist.
+# RUN: llvm-objcopy --set-section-alignment .not_exist=4 %t.3 %t.4
+# RUN: cmp %t.3 %t.4
+
+# RUN: not llvm-objcopy --set-section-alignment=.foo %t /dev/null 2>&1 | \
+# RUN:   FileCheck --check-prefix=MISSING-EQUAL %s
+# MISSING-EQUAL:   error: bad format for --set-section-alignment: missing '='
+
+# RUN: not llvm-objcopy --set-section-alignment==4 %t /dev/null 2>&1 | \
+# RUN:   FileCheck --check-prefix=MISSING-SECTION %s
+# MISSING-SECTION: error: bad format for --set-section-alignment: missing section name
+
+# RUN: not llvm-objcopy --set-section-alignment=.foo=bar %t /dev/null 2>&1 | \
+# RUN:   FileCheck --check-prefix=INVALID-ALIGN %s
+# INVALID-ALIGN:   error: invalid alignment for --set-section-alignment: 'bar'
+
+!ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_REL
+  Machine: EM_X86_64
+Sections:
+  - Name:         .foo
+    Type:         SHT_PROGBITS
+  - Name:         .bar
+    Type:         SHT_NOBITS
+  - Name:         .baz
+    Type:         SHT_NOTE
+    AddressAlign: 4
diff --git a/tools/llvm-objcopy/COFF/COFFObjcopy.cpp b/tools/llvm-objcopy/COFF/COFFObjcopy.cpp
@@ -208,10 +208,11 @@ static Error handleArgs(const CopyConfig &Config, Object &Obj) {
       !Config.SymbolsToGlobalize.empty() || !Config.SymbolsToKeep.empty() ||
       !Config.SymbolsToLocalize.empty() || !Config.SymbolsToWeaken.empty() ||
       !Config.SymbolsToKeepGlobal.empty() || !Config.SectionsToRename.empty() ||
-      !Config.SetSectionFlags.empty() || !Config.SymbolsToRename.empty() ||
-      Config.ExtractDWO || Config.KeepFileSymbols || Config.LocalizeHidden ||
-      Config.PreserveDates || Config.StripDWO || Config.StripNonAlloc ||
-      Config.StripSections || Config.Weaken || Config.DecompressDebugSections ||
+      !Config.SetSectionAlignment.empty() || !Config.SetSectionFlags.empty() ||
+      !Config.SymbolsToRename.empty() || Config.ExtractDWO ||
+      Config.KeepFileSymbols || Config.LocalizeHidden || Config.PreserveDates ||
+      Config.StripDWO || Config.StripNonAlloc || Config.StripSections ||
+      Config.Weaken || Config.DecompressDebugSections ||
       Config.DiscardMode == DiscardType::Locals ||
       !Config.SymbolsToAdd.empty() || Config.EntryExpr) {
     return createStringError(llvm::errc::invalid_argument,

diff --git a/tools/llvm-objcopy/CopyConfig.cpp b/tools/llvm-objcopy/CopyConfig.cpp
@@ -155,6 +155,25 @@ static Expected<SectionRename> parseRenameSectionValue(StringRef FlagValue) {
   return SR;
 }
 
+static Expected<std::pair<StringRef, uint64_t>>
+parseSetSectionAlignment(StringRef FlagValue) {
+  if (!FlagValue.contains('='))
+    return createStringError(
+        errc::invalid_argument,
+        "bad format for --set-section-alignment: missing '='");
+  auto Split = StringRef(FlagValue).split('=');
+  if (Split.first.empty())
+    return createStringError(
+        errc::invalid_argument,
+        "bad format for --set-section-alignment: missing section name");
+  uint64_t NewAlign;
+  if (Split.second.getAsInteger(0, NewAlign))
+    return createStringError(errc::invalid_argument,
+                             "invalid alignment for --set-section-alignment: '%s'",
+                             Split.second.str().c_str());
+  return std::make_pair(Split.first, NewAlign);
+}
+
 static Expected<SectionFlagsUpdate>
 parseSetSectionFlagValue(StringRef FlagValue) {
   if (!StringRef(FlagValue).contains('='))
@@ -489,6 +508,13 @@ Expected<DriverConfig> parseObjcopyOptions(ArrayRef<const char *> ArgsArr) {
                                "multiple renames of section '%s'",
                                SR->OriginalName.str().c_str());
   }
+  for (auto Arg : InputArgs.filtered(OBJCOPY_set_section_alignment)) {
+    Expected<std::pair<StringRef, uint64_t>> NameAndAlign =
+        parseSetSectionAlignment(Arg->getValue());
+    if (!NameAndAlign)
+      return NameAndAlign.takeError();
+    Config.SetSectionAlignment[NameAndAlign->first] = NameAndAlign->second;
+  }
   for (auto Arg : InputArgs.filtered(OBJCOPY_set_section_flags)) {
     Expected<SectionFlagsUpdate> SFU =
         parseSetSectionFlagValue(Arg->getValue());

diff --git a/tools/llvm-objcopy/CopyConfig.h b/tools/llvm-objcopy/CopyConfig.h
@@ -161,6 +161,7 @@ struct CopyConfig {
 
   // Map options
   StringMap<SectionRename> SectionsToRename;
+  StringMap<uint64_t> SetSectionAlignment;
   StringMap<SectionFlagsUpdate> SetSectionFlags;
   StringMap<StringRef> SymbolsToRename;
 

diff --git a/tools/llvm-objcopy/ELF/ELFObjcopy.cpp b/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
@@ -670,6 +670,14 @@ static Error handleArgs(const CopyConfig &Config, Object &Obj,
     }
   }
 
+  if (!Config.SetSectionAlignment.empty()) {
+    for (SectionBase &Sec : Obj.sections()) {
+      auto I = Config.SetSectionAlignment.find(Sec.Name);
+      if (I != Config.SetSectionAlignment.end())
+        Sec.Align = I->second;
+    }
+  }
+
   if (!Config.SetSectionFlags.empty()) {
     for (auto &Sec : Obj.sections()) {
       const auto Iter = Config.SetSectionFlags.find(Sec.Name);

diff --git a/tools/llvm-objcopy/MachO/MachOObjcopy.cpp b/tools/llvm-objcopy/MachO/MachOObjcopy.cpp
@@ -31,13 +31,14 @@ static Error handleArgs(const CopyConfig &Config, Object &Obj) {
       !Config.SymbolsToKeepGlobal.empty() || !Config.SectionsToRename.empty() ||
       !Config.SymbolsToRename.empty() ||
       !Config.UnneededSymbolsToRemove.empty() ||
-      !Config.SetSectionFlags.empty() || !Config.ToRemove.empty() ||
-      Config.ExtractDWO || Config.KeepFileSymbols || Config.LocalizeHidden ||
-      Config.PreserveDates || Config.StripDWO || Config.StripNonAlloc ||
-      Config.StripSections || Config.Weaken || Config.DecompressDebugSections ||
-      Config.StripDebug || Config.StripNonAlloc || Config.StripSections ||
-      Config.StripUnneeded || Config.DiscardMode != DiscardType::None ||
-      !Config.SymbolsToAdd.empty() || Config.EntryExpr) {
+      !Config.SetSectionAlignment.empty() || !Config.SetSectionFlags.empty() ||
+      !Config.ToRemove.empty() || Config.ExtractDWO || Config.KeepFileSymbols ||
+      Config.LocalizeHidden || Config.PreserveDates || Config.StripDWO ||
+      Config.StripNonAlloc || Config.StripSections || Config.Weaken ||
+      Config.DecompressDebugSections || Config.StripDebug ||
+      Config.StripNonAlloc || Config.StripSections || Config.StripUnneeded ||
+      Config.DiscardMode != DiscardType::None || !Config.SymbolsToAdd.empty() ||
+      Config.EntryExpr) {
     return createStringError(llvm::errc::invalid_argument,
                              "option not supported by llvm-objcopy for MachO");
   }

diff --git a/tools/llvm-objcopy/ObjcopyOpts.td b/tools/llvm-objcopy/ObjcopyOpts.td
@@ -75,6 +75,10 @@ defm add_section
          "Make a section named <section> with the contents of <file>.">,
       MetaVarName<"section=file">;
 
+defm set_section_alignment
+    : Eq<"set-section-alignment", "Set alignment for a given section.">,
+      MetaVarName<"section=align">;
+
 defm set_section_flags
     : Eq<"set-section-flags",
          "Set section flags for a given section. Flags supported for GNU "