From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Thu, 6 Oct 2016 14:47:04 +0000 (+0000)
Subject: Refactor to use getSectionContentsAsArray.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=42b70df58d531d039ab74ddc71dc9013a2416fc7;p=llvm

Refactor to use getSectionContentsAsArray.

This centralizes quite a bit of error checking.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283454 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/Object/ELF.h b/include/llvm/Object/ELF.h
index 586f9d643c3..fceb0a19f80 100644
--- a/include/llvm/Object/ELF.h
+++ b/include/llvm/Object/ELF.h
@@ -115,61 +115,33 @@ public:
     return makeArrayRef(section_begin(), section_end());
   }
 
-  const Elf_Sym *symbol_begin(const Elf_Shdr *Sec) const {
+  Elf_Sym_Range symbols(const Elf_Shdr *Sec) const {
     if (!Sec)
-      return nullptr;
+      return makeArrayRef<Elf_Sym>(nullptr, nullptr);
     if (Sec->sh_entsize != sizeof(Elf_Sym))
       report_fatal_error("Invalid symbol size");
-    return reinterpret_cast<const Elf_Sym *>(base() + Sec->sh_offset);
-  }
-  const Elf_Sym *symbol_end(const Elf_Shdr *Sec) const {
-    if (!Sec)
-      return nullptr;
-    uint64_t Size = Sec->sh_size;
-    if (Size % sizeof(Elf_Sym))
-      report_fatal_error("Invalid symbol table size");
-    return symbol_begin(Sec) + Size / sizeof(Elf_Sym);
-  }
-  Elf_Sym_Range symbols(const Elf_Shdr *Sec) const {
-    return makeArrayRef(symbol_begin(Sec), symbol_end(Sec));
-  }
-
-  const Elf_Rela *rela_begin(const Elf_Shdr *sec) const {
-    if (sec->sh_entsize != sizeof(Elf_Rela))
-      report_fatal_error("Invalid relocation entry size");
-    if (sec->sh_offset >= Buf.size())
-      report_fatal_error("Invalid relocation entry offset");
-    return reinterpret_cast<const Elf_Rela *>(base() + sec->sh_offset);
-  }
-
-  const Elf_Rela *rela_end(const Elf_Shdr *sec) const {
-    uint64_t Size = sec->sh_size;
-    if (Size % sizeof(Elf_Rela))
-      report_fatal_error("Invalid relocation table size");
-    return rela_begin(sec) + Size / sizeof(Elf_Rela);
+    auto V = getSectionContentsAsArray<Elf_Sym>(Sec);
+    if (!V)
+      report_fatal_error(V.getError().message());
+    return *V;
   }
 
   Elf_Rela_Range relas(const Elf_Shdr *Sec) const {
-    return makeArrayRef(rela_begin(Sec), rela_end(Sec));
-  }
-
-  const Elf_Rel *rel_begin(const Elf_Shdr *sec) const {
-    if (sec->sh_entsize != sizeof(Elf_Rel))
+    if (Sec->sh_entsize != sizeof(Elf_Rela))
       report_fatal_error("Invalid relocation entry size");
-    if (sec->sh_offset >= Buf.size())
-      report_fatal_error("Invalid relocation entry offset");
-    return reinterpret_cast<const Elf_Rel *>(base() + sec->sh_offset);
-  }
-
-  const Elf_Rel *rel_end(const Elf_Shdr *sec) const {
-    uint64_t Size = sec->sh_size;
-    if (Size % sizeof(Elf_Rel))
-      report_fatal_error("Invalid relocation table size");
-    return rel_begin(sec) + Size / sizeof(Elf_Rel);
+    auto V = getSectionContentsAsArray<Elf_Rela>(Sec);
+    if (!V)
+      report_fatal_error(V.getError().message());
+    return *V;
   }
 
   Elf_Rel_Range rels(const Elf_Shdr *Sec) const {
-    return makeArrayRef(rel_begin(Sec), rel_end(Sec));
+    if (Sec->sh_entsize != sizeof(Elf_Rel))
+      report_fatal_error("Invalid relocation entry size");
+    auto V = getSectionContentsAsArray<Elf_Rel>(Sec);
+    if (!V)
+      report_fatal_error(V.getError().message());
+    return *V;
   }
 
   /// \brief Iterate over program header table.
@@ -202,7 +174,7 @@ public:
   ErrorOr<const Elf_Shdr *> getSection(uint32_t Index) const;
 
   const Elf_Sym *getSymbol(const Elf_Shdr *Sec, uint32_t Index) const {
-    return &*(symbol_begin(Sec) + Index);
+    return &symbols(Sec)[Index];
   }
 
   ErrorOr<StringRef> getSectionName(const Elf_Shdr *Section) const;
@@ -220,7 +192,7 @@ template <class ELFT>
 uint32_t ELFFile<ELFT>::getExtendedSymbolTableIndex(
     const Elf_Sym *Sym, const Elf_Shdr *SymTab,
     ArrayRef<Elf_Word> ShndxTable) const {
-  return getExtendedSymbolTableIndex(Sym, symbol_begin(SymTab), ShndxTable);
+  return getExtendedSymbolTableIndex(Sym, symbols(SymTab).begin(), ShndxTable);
 }
 
 template <class ELFT>
@@ -440,29 +412,23 @@ ErrorOr<StringRef>
 ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const {
   if (Section->sh_type != ELF::SHT_STRTAB)
     return object_error::parse_failed;
-  uint64_t Offset = Section->sh_offset;
-  uint64_t Size = Section->sh_size;
-  if (Offset + Size > Buf.size())
-    return object_error::parse_failed;
-  StringRef Data((const char *)base() + Section->sh_offset, Size);
-  if (Data[Size - 1] != '\0')
+  auto V = getSectionContentsAsArray<char>(Section);
+  if (std::error_code EC = V.getError())
+    return EC;
+  ArrayRef<char> Data = *V;
+  if (Data.back() != '\0')
     return object_error::string_table_non_null_end;
-  return Data;
+  return StringRef(Data.begin(), Data.size());
 }
 
 template <class ELFT>
 ErrorOr<ArrayRef<typename ELFFile<ELFT>::Elf_Word>>
 ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section) const {
   assert(Section.sh_type == ELF::SHT_SYMTAB_SHNDX);
-  const Elf_Word *ShndxTableBegin =
-      reinterpret_cast<const Elf_Word *>(base() + Section.sh_offset);
-  uintX_t Size = Section.sh_size;
-  if (Size % sizeof(uint32_t))
-    return object_error::parse_failed;
-  uintX_t NumSymbols = Size / sizeof(uint32_t);
-  const Elf_Word *ShndxTableEnd = ShndxTableBegin + NumSymbols;
-  if (reinterpret_cast<const char *>(ShndxTableEnd) > Buf.end())
-    return object_error::parse_failed;
+  auto VOrErr = getSectionContentsAsArray<Elf_Word>(&Section);
+  if (std::error_code EC = VOrErr.getError())
+    return EC;
+  ArrayRef<Elf_Word> V = *VOrErr;
   ErrorOr<const Elf_Shdr *> SymTableOrErr = getSection(Section.sh_link);
   if (std::error_code EC = SymTableOrErr.getError())
     return EC;
@@ -470,9 +436,9 @@ ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section) const {
   if (SymTable.sh_type != ELF::SHT_SYMTAB &&
       SymTable.sh_type != ELF::SHT_DYNSYM)
     return object_error::parse_failed;
-  if (NumSymbols != (SymTable.sh_size / sizeof(Elf_Sym)))
+  if (V.size() != (SymTable.sh_size / sizeof(Elf_Sym)))
     return object_error::parse_failed;
-  return makeArrayRef(ShndxTableBegin, ShndxTableEnd);
+  return V;
 }
 
 template <class ELFT>
diff --git a/include/llvm/Object/ELFObjectFile.h b/include/llvm/Object/ELFObjectFile.h
index 07c6364a689..a023d5b3295 100644
--- a/include/llvm/Object/ELFObjectFile.h
+++ b/include/llvm/Object/ELFObjectFile.h
@@ -496,8 +496,8 @@ uint32_t ELFObjectFile<ELFT>::getSymbolFlags(DataRefImpl Sym) const {
     Result |= SymbolRef::SF_Absolute;
 
   if (ESym->getType() == ELF::STT_FILE || ESym->getType() == ELF::STT_SECTION ||
-      ESym == EF.symbol_begin(DotSymtabSec) ||
-      ESym == EF.symbol_begin(DotDynSymSec))
+      ESym == EF.symbols(DotSymtabSec).begin() ||
+      ESym == EF.symbols(DotDynSymSec).begin())
     Result |= SymbolRef::SF_FormatSpecific;
 
   if (EF.getHeader()->e_machine == ELF::EM_ARM) {
diff --git a/test/Object/invalid.test b/test/Object/invalid.test
index 2d5e0e27440..774aa4776b5 100644
--- a/test/Object/invalid.test
+++ b/test/Object/invalid.test
@@ -49,7 +49,7 @@ INVALID-SECTION-SIZE: Invalid section header entry size (e_shentsize) in ELF hea
 
 
 RUN: not llvm-readobj -t %p/Inputs/invalid-symbol-table-size.elf 2>&1 | FileCheck --check-prefix=INVALID-SYMTAB-SIZE %s
-INVALID-SYMTAB-SIZE: Invalid symbol table size
+INVALID-SYMTAB-SIZE: Invalid data was encountered while parsing the file
 
 
 RUN: not llvm-readobj -t %p/Inputs/invalid-xindex-size.elf 2>&1 | FileCheck --check-prefix=INVALID-XINDEX-SIZE %s
@@ -63,4 +63,4 @@ RUN: not llvm-readobj -r %p/Inputs/invalid-relocation-sec-sh_offset.elf-i386 2>&
 RUN:   FileCheck --check-prefix=INVALID-RELOC-SH-OFFSET %s
 RUN: not llvm-readobj -r %p/Inputs/invalid-relocation-sec-sh_offset.elf-x86-64 2>&1 | \
 RUN:   FileCheck --check-prefix=INVALID-RELOC-SH-OFFSET %s
-INVALID-RELOC-SH-OFFSET: Invalid relocation entry offset
+INVALID-RELOC-SH-OFFSET: Invalid data was encountered while parsing the file
diff --git a/tools/llvm-readobj/ELFDumper.cpp b/tools/llvm-readobj/ELFDumper.cpp
index 26acdeeb3f0..318ad2a0abd 100644
--- a/tools/llvm-readobj/ELFDumper.cpp
+++ b/tools/llvm-readobj/ELFDumper.cpp
@@ -3493,7 +3493,7 @@ template <class ELFT> void LLVMStyle<ELFT>::printSections(const ELFO *Obj) {
         const Elf_Shdr *SymSec = unwrapOrError(
             Obj->getSection(&Sym, Symtab, this->dumper()->getShndxTable()));
         if (SymSec == &Sec)
-          printSymbol(Obj, &Sym, Obj->symbol_begin(Symtab), StrTable, false);
+          printSymbol(Obj, &Sym, Obj->symbols(Symtab).begin(), StrTable, false);
       }
     }