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Georgii Rymar
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[llvm-readobj] - Implement --dependent-libraries flag.
There is no way to dump SHT_LLVM_DEPENDENT_LIBRARIES sections currently. This patch implements this. The section is described here: https://llvm.org/docs/Extensions.html#sht-llvm-dependent-libraries-section-dependent-libraries Differential revision: https://reviews.llvm.org/D70665
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‎llvm/docs/CommandGuide/llvm-readobj.rst‎

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@@ -152,6 +152,10 @@ The following options are implemented only for the ELF file format.
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Display demangled symbol names in the output.
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.. option:: --dependent-libraries
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Display the dependent libraries section.
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.. option:: --dyn-relocations
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Display the dynamic relocation entries.

‎llvm/test/tools/llvm-readobj/elf-dependent-libraries.test‎

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@@ -0,0 +1,74 @@
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## Check that we can use the --dependent-libraries option
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## to dump SHT_LLVM_DEPENDENT_LIBRARIES sections.
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## Check how we dump a file that has a single valid SHT_LLVM_DEPENDENT_LIBRARIES
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## section with multiple entries.
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# RUN: yaml2obj --docnum=1 %s -o %t1
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# RUN: llvm-readobj --dependent-libraries %t1 2>&1 | FileCheck %s -DFILE=%t
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# CHECK: DependentLibs [
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# CHECK-NEXT: foo
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# CHECK-NEXT: bar
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# CHECK-NEXT: foo
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# CHECK-NEXT: ]
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--- !ELF
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FileHeader:
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Class: ELFCLASS64
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Data: ELFDATA2LSB
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Type: ET_REL
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Machine: EM_X86_64
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Sections:
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- Name: .deplibs
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Type: SHT_LLVM_DEPENDENT_LIBRARIES
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Libraries: [ foo, bar, foo ]
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## Now, check how we dump a mix of valid, empty and invalid SHT_LLVM_DEPENDENT_LIBRARIES sections.
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# RUN: yaml2obj --docnum=2 %s -o %t2
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# RUN: llvm-readobj --dependent-libraries %t2 2>&1 | FileCheck %s --check-prefix=MIX -DFILE=%t2
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# MIX: DependentLibs [
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# MIX-EMPTY:
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# MIX-NEXT: warning: '[[FILE]]': SHT_LLVM_DEPENDENT_LIBRARIES section at index 1 is broken: the content is not null-terminated
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# MIX-NEXT: abc
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# MIX-EMPTY:
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# MIX-NEXT: warning: '[[FILE]]': SHT_LLVM_DEPENDENT_LIBRARIES section at index 4 is broken: section [index 4] has a sh_offset (0xffff0000) + sh_size (0x4) that is greater than the file size (0x2c0)
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# MIX-NEXT: bar
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# MIX-NEXT: xxx
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# MIX-NEXT: ]
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--- !ELF
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FileHeader:
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Class: ELFCLASS64
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Data: ELFDATA2LSB
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Type: ET_REL
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Machine: EM_X86_64
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Sections:
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## Case 1: test we report a warning for a non-null-terminated section.
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- Name: .deplibs.nonul
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Type: SHT_LLVM_DEPENDENT_LIBRARIES
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Content: "666f6f" ## 'f', 'o', 'o'
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## Case 2: test we can dump an entry from a valid section that has a single entry.
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- Name: .deplibs.single
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Type: SHT_LLVM_DEPENDENT_LIBRARIES
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Libraries: [ abc ]
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## Case 3: test we do not display warnings for an empty section.
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- Name: .deplibs.empty
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Type: SHT_LLVM_DEPENDENT_LIBRARIES
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Content: ""
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## Case 4: test we report a warning when the section offset is invalid.
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- Name: .deplibs.broken.shoffset
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Type: SHT_LLVM_DEPENDENT_LIBRARIES
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Libraries: [ yyy ]
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ShOffset: 0xffff0000
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## Case 5: test we can dump all entries from a valid section that has more than one entry.
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- Name: .deplibs.multiple
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Type: SHT_LLVM_DEPENDENT_LIBRARIES
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Libraries: [ bar, xxx ]
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## llvm-readelf doesn't support --dependent-libraries yet.
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# RUN: llvm-readelf --dependent-libraries %t1 2>&1 | FileCheck %s --check-prefix=READELF
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# READELF: printDependentLibs not implemented!

‎llvm/tools/llvm-readobj/ELFDumper.cpp‎

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@@ -193,6 +193,7 @@ template <typename ELFT> class ELFDumper : public ObjDumper {
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void printFileHeaders() override;
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void printSectionHeaders() override;
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void printRelocations() override;
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void printDependentLibs() override;
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void printDynamicRelocations() override;
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void printSymbols(bool PrintSymbols, bool PrintDynamicSymbols) override;
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void printHashSymbols() override;
@@ -617,6 +618,7 @@ template <typename ELFT> class DumpStyle {
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virtual void printSymbols(const ELFFile<ELFT> *Obj, bool PrintSymbols,
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bool PrintDynamicSymbols) = 0;
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virtual void printHashSymbols(const ELFFile<ELFT> *Obj) {}
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virtual void printDependentLibs(const ELFFile<ELFT> *Obj) = 0;
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virtual void printDynamic(const ELFFile<ELFT> *Obj) {}
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virtual void printDynamicRelocations(const ELFFile<ELFT> *Obj) = 0;
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virtual void printSymtabMessage(const ELFFile<ELFT> *Obj, StringRef Name,
@@ -687,6 +689,7 @@ template <typename ELFT> class GNUStyle : public DumpStyle<ELFT> {
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void printSymbols(const ELFO *Obj, bool PrintSymbols,
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bool PrintDynamicSymbols) override;
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void printHashSymbols(const ELFO *Obj) override;
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void printDependentLibs(const ELFFile<ELFT> *Obj) override;
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void printDynamic(const ELFFile<ELFT> *Obj) override;
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void printDynamicRelocations(const ELFO *Obj) override;
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void printSymtabMessage(const ELFO *Obj, StringRef Name, size_t Offset,
@@ -807,6 +810,7 @@ template <typename ELFT> class LLVMStyle : public DumpStyle<ELFT> {
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void printSectionHeaders(const ELFO *Obj) override;
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void printSymbols(const ELFO *Obj, bool PrintSymbols,
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bool PrintDynamicSymbols) override;
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void printDependentLibs(const ELFFile<ELFT> *Obj) override;
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void printDynamic(const ELFFile<ELFT> *Obj) override;
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void printDynamicRelocations(const ELFO *Obj) override;
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void printProgramHeaders(const ELFO *Obj, bool PrintProgramHeaders,
@@ -2054,6 +2058,10 @@ template <typename ELFT> void ELFDumper<ELFT>::printVersionInfo() {
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SymbolVersionNeedSection);
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}
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template <class ELFT> void ELFDumper<ELFT>::printDependentLibs() {
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ELFDumperStyle->printDependentLibs(ObjF->getELFFile());
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}
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template <class ELFT> void ELFDumper<ELFT>::printDynamicRelocations() {
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ELFDumperStyle->printDynamicRelocations(ObjF->getELFFile());
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}
@@ -4873,6 +4881,11 @@ void GNUStyle<ELFT>::printELFLinkerOptions(const ELFFile<ELFT> *Obj) {
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OS << "printELFLinkerOptions not implemented!\n";
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}
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template <class ELFT>
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void GNUStyle<ELFT>::printDependentLibs(const ELFFile<ELFT> *Obj) {
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OS << "printDependentLibs not implemented!\n";
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}
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// Used for printing section names in places where possible errors can be
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// ignored.
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static StringRef getSectionName(const SectionRef &Sec) {
@@ -6143,6 +6156,42 @@ void LLVMStyle<ELFT>::printELFLinkerOptions(const ELFFile<ELFT> *Obj) {
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}
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}
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template <class ELFT>
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void LLVMStyle<ELFT>::printDependentLibs(const ELFFile<ELFT> *Obj) {
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ListScope L(W, "DependentLibs");
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auto Warn = [this](unsigned SecNdx, StringRef Msg) {
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this->reportUniqueWarning(
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createError("SHT_LLVM_DEPENDENT_LIBRARIES section at index " +
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Twine(SecNdx) + " is broken: " + Msg));
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};
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unsigned I = -1;
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for (const Elf_Shdr &Shdr : unwrapOrError(this->FileName, Obj->sections())) {
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++I;
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if (Shdr.sh_type != ELF::SHT_LLVM_DEPENDENT_LIBRARIES)
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continue;
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Expected<ArrayRef<uint8_t>> ContentsOrErr = Obj->getSectionContents(&Shdr);
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if (!ContentsOrErr) {
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Warn(I, toString(ContentsOrErr.takeError()));
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continue;
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}
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ArrayRef<uint8_t> Contents = *ContentsOrErr;
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if (!Contents.empty() && Contents.back() != 0) {
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Warn(I, "the content is not null-terminated");
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continue;
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}
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for (const uint8_t *I = Contents.begin(), *E = Contents.end(); I < E;) {
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StringRef Lib((const char *)I);
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W.printString(Lib);
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I += Lib.size() + 1;
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}
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}
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}
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template <class ELFT>
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void LLVMStyle<ELFT>::printStackSizes(const ELFObjectFile<ELFT> *Obj) {
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ListScope L(W, "StackSizes");

‎llvm/tools/llvm-readobj/ObjDumper.h‎

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@@ -53,6 +53,7 @@ class ObjDumper {
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virtual void printUnwindInfo() = 0;
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// Only implemented for ELF at this time.
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virtual void printDependentLibs() {}
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virtual void printDynamicRelocations() { }
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virtual void printDynamicTable() { }
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virtual void printNeededLibraries() { }

‎llvm/tools/llvm-readobj/llvm-readobj.cpp‎

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@@ -58,6 +58,11 @@ namespace opts {
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"--section-groups and --elf-hash-histogram."));
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cl::alias AllShort("a", cl::desc("Alias for --all"), cl::aliasopt(All));
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// --dependent-libraries
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cl::opt<bool>
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DependentLibraries("dependent-libraries",
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cl::desc("Display the dependent libraries section"));
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// --headers -e
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cl::opt<bool>
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Headers("headers",
@@ -489,6 +494,8 @@ static void dumpObject(const ObjectFile *Obj, ScopedPrinter &Writer,
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if (opts::VersionInfo)
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Dumper->printVersionInfo();
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if (Obj->isELF()) {
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if (opts::DependentLibraries)
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Dumper->printDependentLibs();
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if (opts::ELFLinkerOptions)
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Dumper->printELFLinkerOptions();
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if (opts::ArchSpecificInfo)

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