[llvm-readelf/llvm-objdump] - Improve/refactor the implementation of SHT_LLVM_ADDRSIG section dumping.

This patch:

* Adds a llvm-readobj/llvm-readelf test file for SHT_LLVM_ADDRSIG sections. (we do not have any)
* Enables dumping of SHT_LLVM_ADDRSIG with --all.
* Changes the logic to report a warning instead of an error when something goes wrong during dumping
  (allows to continue dumping SHT_LLVM_ADDRSIG and other sections on error).
* Refactors a piece of logic to a new toULEB128Array helper which might be used for GNU-style
  dumping implementation.

Differential revision: https://reviews.llvm.org/D68383

llvm-svn: 373890

Author: George Rimar

llvm/test/tools/llvm-readobj/all.test

@@ -14,6 +14,7 @@
 # ALL: Version symbols {
 # ALL: SHT_GNU_verdef {
 # ALL: SHT_GNU_verneed {
+# ALL: Addrsig [
 # ALL: Notes [
 # ALL: StackSizes [
 

llvm/test/tools/llvm-readobj/elf-addrsig.test

@@ -0,0 +1,84 @@
+## Show that llvm-readobj can dump SHT_LLVM_ADDRSIG sections.
+
+# RUN: yaml2obj --docnum=1 %s -o %t1.o
+# RUN: llvm-readobj --addrsig %t1.o | FileCheck -DFILE=%t1.o %s --check-prefix LLVM
+# RUN: not llvm-readelf --addrsig %t1.o 2>&1 | FileCheck -DFILE=%t1.o %s --check-prefix GNU
+
+# LLVM:      Addrsig [
+# LLVM-NEXT:   Sym: foo (1)
+# LLVM-NEXT:   Sym: bar (2)
+# LLVM-NEXT: ]
+
+# GNU: error: '[[FILE]]': --addrsig: not implemented
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name: .llvm_addrsig
+    Type: SHT_LLVM_ADDRSIG
+    Symbols:
+      - Name: foo
+      - Name: bar
+Symbols:
+  - Name: foo
+  - Name: bar
+
+## Check that llvm-readobj dumps any SHT_LLVM_ADDRSIG section when --all
+## is specified for LLVM style, but not for GNU style.
+## TODO: Refine the llvm-readelf check when GNU-style dumping is implemented.
+
+# RUN: llvm-readobj --all %t1.o | FileCheck %s --check-prefix LLVM
+# RUN: llvm-readelf --all %t1.o 2>&1 | FileCheck %s --implicit-check-not=warning --implicit-check-not=error
+
+## Check we report a warning when SHT_LLVM_ADDRSIG is broken (e.g. contains a malformed uleb128).
+
+# RUN: yaml2obj --docnum=2 %s -o %t2.o
+# RUN: llvm-readobj --addrsig %t2.o 2>&1 | FileCheck %s -DFILE=%t2.o --check-prefix=MALFORMED
+
+# MALFORMED: warning: '[[FILE]]': malformed uleb128, extends past end
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name: .llvm_addrsig
+    Type: SHT_LLVM_ADDRSIG
+    Content: "FF"
+
+## Check we report a warning when SHT_LLVM_ADDRSIG references a symbol that can't be
+## dumped (e.g. the index value is larger than the number of symbols in .symtab).
+
+# RUN: yaml2obj --docnum=3 %s -o %t3.o
+# RUN: llvm-readobj --addrsig %t3.o 2>&1 | FileCheck %s -DFILE=%t3.o --check-prefix=INVALID-INDEX
+
+# INVALID-INDEX:       Addrsig [
+# INVALID-INDEX-NEXT:    Sym: foo (1)
+# INVALID-INDEX-EMPTY:
+# INVALID-INDEX-NEXT:    warning: '[[FILE]]': unable to get symbol from section [index 2]: invalid symbol index (255)
+# INVALID-INDEX-NEXT:    Sym: <?> (255)
+# INVALID-INDEX-NEXT:    Sym: bar (2)
+# INVALID-INDEX-NEXT:  ]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name: .llvm_addrsig
+    Type: SHT_LLVM_ADDRSIG
+    Symbols:
+      - Index: 1
+      - Index: 255
+      - Index: 2
+Symbols:
+  - Name: foo
+  - Name: bar

llvm/tools/llvm-readobj/ELFDumper.cpp

@@ -302,7 +302,7 @@ template <typename ELFT> class ELFDumper : public ObjDumper {
   void getSectionNameIndex(const Elf_Sym *Symbol, const Elf_Sym *FirstSym,
                            StringRef &SectionName,
                            unsigned &SectionIndex) const;
-  std::string getStaticSymbolName(uint32_t Index) const;
+  Expected<std::string> getStaticSymbolName(uint32_t Index) const;
   std::string getDynamicString(uint64_t Value) const;
   StringRef getSymbolVersionByIndex(StringRef StrTab,
                                     uint32_t VersionSymbolIndex,
@@ -754,17 +754,22 @@ static std::string maybeDemangle(StringRef Name) {
 }
 
 template <typename ELFT>
-std::string ELFDumper<ELFT>::getStaticSymbolName(uint32_t Index) const {
+Expected<std::string>
+ELFDumper<ELFT>::getStaticSymbolName(uint32_t Index) const {
   const ELFFile<ELFT> *Obj = ObjF->getELFFile();
-  StringRef StrTable = unwrapOrError(
-      ObjF->getFileName(), Obj->getStringTableForSymtab(*DotSymtabSec));
-  Elf_Sym_Range Syms =
-      unwrapOrError(ObjF->getFileName(), Obj->symbols(DotSymtabSec));
-  if (Index >= Syms.size())
-    reportError(createError("Invalid symbol index"), ObjF->getFileName());
-  const Elf_Sym *Sym = &Syms[Index];
-  return maybeDemangle(
-      unwrapOrError(ObjF->getFileName(), Sym->getName(StrTable)));
+  Expected<const typename ELFT::Sym *> SymOrErr =
+      Obj->getSymbol(DotSymtabSec, Index);
+  if (!SymOrErr)
+    return SymOrErr.takeError();
+
+  Expected<StringRef> StrTabOrErr = Obj->getStringTableForSymtab(*DotSymtabSec);
+  if (!StrTabOrErr)
+    return StrTabOrErr.takeError();
+
+  Expected<StringRef> NameOrErr = (*SymOrErr)->getName(*StrTabOrErr);
+  if (!NameOrErr)
+    return NameOrErr.takeError();
+  return maybeDemangle(*NameOrErr);
 }
 
 template <typename ELFT>
@@ -4047,7 +4052,7 @@ void GNUStyle<ELFT>::printCGProfile(const ELFFile<ELFT> *Obj) {
 
 template <class ELFT>
 void GNUStyle<ELFT>::printAddrsig(const ELFFile<ELFT> *Obj) {
-    OS << "GNUStyle::printAddrsig not implemented\n";
+  reportError(createError("--addrsig: not implemented"), this->FileName);
 }
 
 static StringRef getGenericNoteTypeName(const uint32_t NT) {
@@ -5723,14 +5728,35 @@ void LLVMStyle<ELFT>::printCGProfile(const ELFFile<ELFT> *Obj) {
                           this->dumper()->getDotCGProfileSec()));
   for (const Elf_CGProfile &CGPE : CGProfile) {
     DictScope D(W, "CGProfileEntry");
-    W.printNumber("From", this->dumper()->getStaticSymbolName(CGPE.cgp_from),
-                  CGPE.cgp_from);
-    W.printNumber("To", this->dumper()->getStaticSymbolName(CGPE.cgp_to),
-                  CGPE.cgp_to);
+    W.printNumber(
+        "From",
+        unwrapOrError(this->FileName,
+                      this->dumper()->getStaticSymbolName(CGPE.cgp_from)),
+        CGPE.cgp_from);
+    W.printNumber(
+        "To",
+        unwrapOrError(this->FileName,
+                      this->dumper()->getStaticSymbolName(CGPE.cgp_to)),
+        CGPE.cgp_to);
     W.printNumber("Weight", CGPE.cgp_weight);
   }
 }
 
+static Expected<std::vector<uint64_t>> toULEB128Array(ArrayRef<uint8_t> Data) {
+  std::vector<uint64_t> Ret;
+  const uint8_t *Cur = Data.begin();
+  const uint8_t *End = Data.end();
+  while (Cur != End) {
+    unsigned Size;
+    const char *Err;
+    Ret.push_back(decodeULEB128(Cur, &Size, End, &Err));
+    if (Err)
+      return createError(Err);
+    Cur += Size;
+  }
+  return Ret;
+}
+
 template <class ELFT>
 void LLVMStyle<ELFT>::printAddrsig(const ELFFile<ELFT> *Obj) {
   ListScope L(W, "Addrsig");
@@ -5739,18 +5765,20 @@ void LLVMStyle<ELFT>::printAddrsig(const ELFFile<ELFT> *Obj) {
   ArrayRef<uint8_t> Contents = unwrapOrError(
       this->FileName,
       Obj->getSectionContents(this->dumper()->getDotAddrsigSec()));
-  const uint8_t *Cur = Contents.begin();
-  const uint8_t *End = Contents.end();
-  while (Cur != End) {
-    unsigned Size;
-    const char *Err;
-    uint64_t SymIndex = decodeULEB128(Cur, &Size, End, &Err);
-    if (Err)
-      reportError(createError(Err), this->FileName);
+  Expected<std::vector<uint64_t>> V = toULEB128Array(Contents);
+  if (!V) {
+    reportWarning(V.takeError(), this->FileName);
+    return;
+  }
 
-    W.printNumber("Sym", this->dumper()->getStaticSymbolName(SymIndex),
-                  SymIndex);
-    Cur += Size;
+  for (uint64_t Sym : *V) {
+    Expected<std::string> NameOrErr = this->dumper()->getStaticSymbolName(Sym);
+    if (NameOrErr) {
+      W.printNumber("Sym", *NameOrErr, Sym);
+      continue;
+    }
+    reportWarning(NameOrErr.takeError(), this->FileName);
+    W.printNumber("Sym", "<?>", Sym);
   }
 }
 

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

@@ -691,8 +691,10 @@ int main(int argc, const char *argv[]) {
     opts::UnwindInfo = true;
     opts::SectionGroups = true;
     opts::HashHistogram = true;
-    if (opts::Output == opts::LLVM)
+    if (opts::Output == opts::LLVM) {
+      opts::Addrsig = true;
       opts::PrintStackSizes = true;
+    }
   }
 
   if (opts::Headers) {