[llvm-readelf] - Implement --addrsig option.

We have `--addrsig` implemented for `llvm-readobj`.
Usually it is convenient to use a single tool for dumping,
so it seems we might want to implement `--addrsig` for `llvm-readelf` too.

I've selected a simple output format which is a bit similar to one,
used for dumping of the symbol table. It looks like:

```
Address-significant symbols section '.llvm_addrsig' contains 2 entries:
   Num: Name
     1: foo
     2: bar
```

Differential revision: https://reviews.llvm.org/D88835

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

@@ -1,15 +1,21 @@
 ## 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: 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
+# RUN: llvm-readelf --addrsig %t1.o | \
+# RUN:   FileCheck -DFILE=%t1.o %s --strict-whitespace --match-full-lines --check-prefix=GNU
 
 # LLVM:      Addrsig [
 # LLVM-NEXT:   Sym: foo (1)
 # LLVM-NEXT:   Sym: bar (2)
 # LLVM-NEXT: ]
 
-# GNU: error: '[[FILE]]': --addrsig: not implemented
+#       GNU:Address-significant symbols section '.llvm_addrsig' contains 2 entries:
+#  GNU-NEXT:   Num: Name
+#  GNU-NEXT:     1: foo
+#  GNU-NEXT:     2: bar
+# GNU-EMPTY:
+#   GNU-NOT:{{.}}
 
 --- !ELF
 FileHeader:
@@ -17,29 +23,48 @@ FileHeader:
   Data:  ELFDATA2LSB
   Type:  ET_DYN
 Sections:
-  - Name: .llvm_addrsig
+  - Name:    .llvm_addrsig
-    Type: SHT_LLVM_ADDRSIG
+    ShName:  [[NAME=<none>]]
+    Type:    SHT_LLVM_ADDRSIG
     Symbols: [ foo, bar ]
 Symbols:
   - Name: foo
   - Name: bar
 
+## Check what we print when it is impossible to read the name of the SHT_LLVM_ADDRSIG section.
+## llvm-readelf reports a warning in this case.
+
+# RUN: yaml2obj --docnum=1 -DNAME=0xff %s -o %t1.name.o
+# RUN: llvm-readobj --addrsig %t1.name.o 2>&1 | \
+# RUN:   FileCheck -DFILE=%t1.name.o %s --check-prefix=LLVM --implicit-check-not=warning:
+# RUN: llvm-readelf --addrsig %t1.name.o 2>&1 | \
+# RUN:   FileCheck -DFILE=%t1.name.o %s --check-prefix=NAME-GNU --implicit-check-not=warning:
+
+# NAME-GNU: warning: '[[FILE]]': unable to get the name of SHT_LLVM_ADDRSIG section with index 1: a section [index 1] has an invalid sh_name (0xff) offset which goes past the end of the section name string table
+# NAME-GNU:      Address-significant symbols section '<?>' contains 2 entries:
+# NAME-GNU-NEXT:    Num: Name
+# NAME-GNU-NEXT:      1: foo
+# NAME-GNU-NEXT:      2: 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-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
+# RUN: llvm-readelf --all %t1.o | FileCheck %s --implicit-check-not="Address-significant"
 
 ## Check we report a warning when the content of the SHT_LLVM_ADDRSIG section
 ## is broken (e.g. contains a malformed uleb128).
 
 # RUN: yaml2obj --docnum=2 %s -o %t2.1.o
-# RUN: llvm-readobj --addrsig %t2.1.o 2>&1 | FileCheck %s -DFILE=%t2.1.o --check-prefix=MALFORMED
+# RUN: llvm-readobj --addrsig %t2.1.o 2>&1 | FileCheck %s -DFILE=%t2.1.o --check-prefix=MALFORMED-LLVM
+# RUN: llvm-readelf --addrsig %t2.1.o 2>&1 | FileCheck %s -DFILE=%t2.1.o --check-prefix=MALFORMED-GNU
 
-# MALFORMED:      Addrsig [
+# MALFORMED-LLVM:      Addrsig [
-# MALFORMED-NEXT: warning: '[[FILE]]': unable to decode SHT_LLVM_ADDRSIG section with index 1: malformed uleb128, extends past end
+# MALFORMED-LLVM-NEXT: warning: '[[FILE]]': unable to decode SHT_LLVM_ADDRSIG section with index 1: malformed uleb128, extends past end
-# MALFORMED-NEXT: ]
+# MALFORMED-LLVM-NEXT: ]
+
+# MALFORMED-GNU:    warning: '[[FILE]]': unable to decode SHT_LLVM_ADDRSIG section with index 1: malformed uleb128, extends past end
+# MALFORMED-GNU-NOT:{{.}}
 
 --- !ELF
 FileHeader:
@@ -55,24 +80,36 @@ Sections:
 ## Check we report a warning when the content of the SHT_LLVM_ADDRSIG section can't be read.
 
 # RUN: yaml2obj --docnum=2 -DOFFSET=0xffffffff %s -o %t2.2.o
-# RUN: llvm-readobj --addrsig %t2.2.o 2>&1 | FileCheck %s -DFILE=%t2.2.o --check-prefix=BROKEN-SEC
+# RUN: llvm-readobj --addrsig %t2.2.o 2>&1 | FileCheck %s -DFILE=%t2.2.o --check-prefix=BROKEN-SEC-LLVM
+# RUN: llvm-readelf --addrsig %t2.2.o 2>&1 | FileCheck %s -DFILE=%t2.2.o --check-prefix=BROKEN-SEC-GNU
 
-# BROKEN-SEC:      Addrsig [
+# BROKEN-SEC-LLVM:      Addrsig [
-# BROKEN-SEC-NEXT: warning: '[[FILE]]': section [index 1] has a sh_offset (0xffffffff) + sh_size (0x1) that is greater than the file size (0x168)
+# BROKEN-SEC-LLVM-NEXT: warning: '[[FILE]]': section [index 1] has a sh_offset (0xffffffff) + sh_size (0x1) that is greater than the file size (0x168)
-# BROKEN-SEC-NEXT: ]
+# BROKEN-SEC-LLVM-NEXT: ]
+
+# BROKEN-SEC-GNU:    warning: '[[FILE]]': section [index 1] has a sh_offset (0xffffffff) + sh_size (0x1) that is greater than the file size (0x168)
+# BROKEN-SEC-GNU-NOT:{{.}}
 
 ## 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
+# RUN: llvm-readobj --addrsig %t3.o 2>&1 | FileCheck %s -DFILE=%t3.o --check-prefix=INVALID-INDEX-LLVM
+# RUN: llvm-readelf --addrsig %t3.o 2>&1 | FileCheck %s -DFILE=%t3.o --check-prefix=INVALID-INDEX-GNU
 
-# INVALID-INDEX:      Addrsig [
+# INVALID-INDEX-LLVM:      Addrsig [
-# INVALID-INDEX-NEXT:   Sym: foo (1)
+# INVALID-INDEX-LLVM-NEXT:   Sym: foo (1)
-# INVALID-INDEX-NEXT:   warning: '[[FILE]]': unable to read the name of symbol with index 255: unable to get symbol from section [index 2]: invalid symbol index (255)
+# INVALID-INDEX-LLVM-NEXT:   warning: '[[FILE]]': unable to read the name of symbol with index 255: unable to get symbol from section [index 2]: invalid symbol index (255)
-# INVALID-INDEX-NEXT:   Sym: <?> (255)
+# INVALID-INDEX-LLVM-NEXT:   Sym: <?> (255)
-# INVALID-INDEX-NEXT:   Sym: bar (2)
+# INVALID-INDEX-LLVM-NEXT:   Sym: bar (2)
-# INVALID-INDEX-NEXT: ]
+# INVALID-INDEX-LLVM-NEXT: ]
+
+# INVALID-INDEX-GNU:      Address-significant symbols section '.llvm_addrsig' contains 3 entries:
+# INVALID-INDEX-GNU-NEXT:    Num: Name
+# INVALID-INDEX-GNU-NEXT:      1: foo
+# INVALID-INDEX-GNU-NEXT: warning: '[[FILE]]': unable to read the name of symbol with index 255: unable to get symbol from section [index 2]: invalid symbol index (255)
+# INVALID-INDEX-GNU-NEXT:      2: <?>
+# INVALID-INDEX-GNU-NEXT:      3: bar
 
 --- !ELF
 FileHeader:

test/tools/llvm-readobj/ELF/demangle.test

@@ -68,17 +68,17 @@
 
 ## Check GNU output style.
 # RUN: llvm-readelf --symbols --relocations --dyn-symbols --dyn-relocations \
-# RUN:              --elf-section-groups --demangle %t.so > %t.gnu.long
+# RUN:              --elf-section-groups --addrsig --demangle %t.so > %t.gnu.long
 # RUN: llvm-readelf --symbols --relocations --dyn-symbols --dyn-relocations \
-# RUN:              --elf-section-groups -C %t.so > %t.gnu.short
+# RUN:              --elf-section-groups --addrsig -C %t.so > %t.gnu.short
 # RUN: FileCheck %s --input-file %t.gnu.long --check-prefixes=GNU-COMMON,GNU-DEMANGLE
 # RUN: diff %t.gnu.long %t.gnu.short
 
 ## Check that default is no demangling.
 # RUN: llvm-readelf --symbols --relocations --dyn-symbols --dyn-relocations \
-# RUN:              --elf-section-groups %t.so > %t.gnu.default
+# RUN:              --elf-section-groups --addrsig %t.so > %t.gnu.default
 # RUN: llvm-readelf --symbols --relocations --dyn-symbols --dyn-relocations \
-# RUN:              --elf-section-groups --demangle=false %t.so > %t.gnu.nodemangle
+# RUN:              --elf-section-groups --addrsig --demangle=false %t.so > %t.gnu.nodemangle
 # RUN: FileCheck %s --input-file %t.gnu.default --check-prefixes=GNU-COMMON,GNU-MANGLED
 # RUN: diff %t.gnu.default %t.gnu.nodemangle
 
@@ -110,6 +110,13 @@
 # GNU-DEMANGLE-SAME: [foo(char)]
 # GNU-MANGLED-SAME:  [_Z3fooc]
 
+# GNU-COMMON:       Address-significant symbols section '.llvm_addrsig' contains 2 entries:
+# GNU-COMMON:          Num: Name
+# GNU-DEMANGLE-NEXT:     1: foo(char)
+# GNU-DEMANGLE-NEXT:     2: blah(float)
+# GNU-MANGLED-NEXT:      1: _Z3fooc
+# GNU-MANGLED-NEXT:      2: _Z4blahf
+
 !ELF
 FileHeader:
   Class:           ELFCLASS64

tools/llvm-readobj/ELFDumper.cpp

@@ -4722,8 +4722,62 @@ template <class ELFT> void GNUStyle<ELFT>::printCGProfile() {
   OS << "GNUStyle::printCGProfile not implemented\n";
 }
 
+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>
+static Expected<std::vector<uint64_t>>
+decodeAddrsigSection(const ELFFile<ELFT> &Obj, const typename ELFT::Shdr &Sec) {
+  Expected<ArrayRef<uint8_t>> ContentsOrErr = Obj.getSectionContents(Sec);
+  if (!ContentsOrErr)
+    return ContentsOrErr.takeError();
+
+  if (Expected<std::vector<uint64_t>> SymsOrErr =
+          toULEB128Array(*ContentsOrErr))
+    return *SymsOrErr;
+  else
+    return createError("unable to decode " + describe(Obj, Sec) + ": " +
+                       toString(SymsOrErr.takeError()));
+}
+
 template <class ELFT> void GNUStyle<ELFT>::printAddrsig() {
-  reportError(createError("--addrsig: not implemented"), this->FileName);
+  const Elf_Shdr *Sec = this->dumper().getDotAddrsigSec();
+  if (!Sec)
+    return;
+
+  Expected<std::vector<uint64_t>> SymsOrErr =
+      decodeAddrsigSection(this->Obj, *Sec);
+  if (!SymsOrErr) {
+    this->reportUniqueWarning(SymsOrErr.takeError());
+    return;
+  }
+
+  StringRef Name = this->getPrintableSectionName(*Sec);
+  OS << "\nAddress-significant symbols section '" << Name << "'"
+     << " contains " << SymsOrErr->size() << " entries:\n";
+  OS << "   Num: Name\n";
+
+  Field Fields[2] = {0, 8};
+  size_t SymIndex = 0;
+  for (uint64_t Sym : *SymsOrErr) {
+    Fields[0].Str = to_string(format_decimal(++SymIndex, 6)) + ":";
+    Fields[1].Str = this->dumper().getStaticSymbolName(Sym);
+    for (const Field &Entry : Fields)
+      printField(Entry);
+    OS << "\n";
+  }
 }
 
 template <typename ELFT>
@@ -6417,39 +6471,16 @@ template <class ELFT> void LLVMStyle<ELFT>::printCGProfile() {
   }
 }
 
-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() {
   ListScope L(W, "Addrsig");
   const Elf_Shdr *Sec = this->dumper().getDotAddrsigSec();
   if (!Sec)
     return;
 
-  Expected<ArrayRef<uint8_t>> ContentsOrErr =
+  Expected<std::vector<uint64_t>> SymsOrErr =
-      this->Obj.getSectionContents(*Sec);
+      decodeAddrsigSection(this->Obj, *Sec);
-  if (!ContentsOrErr) {
-    this->reportUniqueWarning(ContentsOrErr.takeError());
-    return;
-  }
-
-  Expected<std::vector<uint64_t>> SymsOrErr = toULEB128Array(*ContentsOrErr);
   if (!SymsOrErr) {
-    this->reportUniqueWarning(createError("unable to decode " +
+    this->reportUniqueWarning(SymsOrErr.takeError());
-                                          describe(this->Obj, *Sec) + ": " +
-                                          toString(SymsOrErr.takeError())));
     return;
   }