[llvm] r316805 - Add support for writing 64-bit symbol tables for archives when offsets become too large for 32-bit
Jake Ehrlich via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 27 15:26:37 PDT 2017
Author: jakehehrlich
Date: Fri Oct 27 15:26:37 2017
New Revision: 316805
URL: http://llvm.org/viewvc/llvm-project?rev=316805&view=rev
Log:
Add support for writing 64-bit symbol tables for archives when offsets become too large for 32-bit
This should fix https://bugs.llvm.org//show_bug.cgi?id=34189
This change makes it so that if writing a K_GNU style archive, you need
to output a > 32-bit offset it should output in K_GNU64 style instead.
Differential Revision: https://reviews.llvm.org/D36812
Added:
llvm/trunk/test/Object/archive-SYM64-write.test
Modified:
llvm/trunk/lib/Object/ArchiveWriter.cpp
Modified: llvm/trunk/lib/Object/ArchiveWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/ArchiveWriter.cpp?rev=316805&r1=316804&r2=316805&view=diff
==============================================================================
--- llvm/trunk/lib/Object/ArchiveWriter.cpp (original)
+++ llvm/trunk/lib/Object/ArchiveWriter.cpp Fri Oct 27 15:26:37 2017
@@ -122,11 +122,11 @@ static void printWithSpacePadding(raw_os
static bool isBSDLike(object::Archive::Kind Kind) {
switch (Kind) {
case object::Archive::K_GNU:
+ case object::Archive::K_GNU64:
return false;
case object::Archive::K_BSD:
case object::Archive::K_DARWIN:
return true;
- case object::Archive::K_GNU64:
case object::Archive::K_DARWIN64:
case object::Archive::K_COFF:
break;
@@ -134,8 +134,8 @@ static bool isBSDLike(object::Archive::K
llvm_unreachable("not supported for writting");
}
-static void print32(raw_ostream &Out, object::Archive::Kind Kind,
- uint32_t Val) {
+template <class T>
+static void print(raw_ostream &Out, object::Archive::Kind Kind, T Val) {
if (isBSDLike(Kind))
support::endian::Writer<support::little>(Out).write(Val);
else
@@ -216,6 +216,20 @@ static std::string computeRelativePath(S
return Relative.str();
}
+static bool is64BitKind(object::Archive::Kind Kind) {
+ switch (Kind) {
+ case object::Archive::K_GNU:
+ case object::Archive::K_BSD:
+ case object::Archive::K_DARWIN:
+ case object::Archive::K_COFF:
+ return false;
+ case object::Archive::K_DARWIN64:
+ case object::Archive::K_GNU64:
+ return true;
+ }
+ llvm_unreachable("not supported for writting");
+}
+
static void addToStringTable(raw_ostream &Out, StringRef ArcName,
const NewArchiveMember &M, bool Thin) {
StringRef ID = M.Buf->getBufferIdentifier();
@@ -288,6 +302,14 @@ static bool isArchiveSymbol(const object
return true;
}
+static void printNBits(raw_ostream &Out, object::Archive::Kind Kind,
+ uint64_t Val) {
+ if (is64BitKind(Kind))
+ print<uint64_t>(Out, Kind, Val);
+ else
+ print<uint32_t>(Out, Kind, Val);
+}
+
static void writeSymbolTable(raw_ostream &Out, object::Archive::Kind Kind,
bool Deterministic, ArrayRef<MemberData> Members,
StringRef StringTable) {
@@ -299,9 +321,11 @@ static void writeSymbolTable(raw_ostream
NumSyms += M.Symbols.size();
unsigned Size = 0;
- Size += 4; // Number of entries
+ Size += is64BitKind(Kind) ? 8 : 4; // Number of entries
if (isBSDLike(Kind))
Size += NumSyms * 8; // Table
+ else if (is64BitKind(Kind))
+ Size += NumSyms * 8; // Table
else
Size += NumSyms * 4; // Table
if (isBSDLike(Kind))
@@ -318,27 +342,30 @@ static void writeSymbolTable(raw_ostream
if (isBSDLike(Kind))
printBSDMemberHeader(Out, Out.tell(), "__.SYMDEF", now(Deterministic), 0, 0,
0, Size);
+ else if (is64BitKind(Kind))
+ printGNUSmallMemberHeader(Out, "/SYM64", now(Deterministic), 0, 0, 0, Size);
else
printGNUSmallMemberHeader(Out, "", now(Deterministic), 0, 0, 0, Size);
uint64_t Pos = Out.tell() + Size;
if (isBSDLike(Kind))
- print32(Out, Kind, NumSyms * 8);
+ print<uint32_t>(Out, Kind, NumSyms * 8);
else
- print32(Out, Kind, NumSyms);
+ printNBits(Out, Kind, NumSyms);
for (const MemberData &M : Members) {
for (unsigned StringOffset : M.Symbols) {
if (isBSDLike(Kind))
- print32(Out, Kind, StringOffset);
- print32(Out, Kind, Pos); // member offset
+ print<uint32_t>(Out, Kind, StringOffset);
+ printNBits(Out, Kind, Pos); // member offset
}
Pos += M.Header.size() + M.Data.size() + M.Padding.size();
}
if (isBSDLike(Kind))
- print32(Out, Kind, StringTable.size()); // byte count of the string table
+ // byte count of the string table
+ print<uint32_t>(Out, Kind, StringTable.size());
Out << StringTable;
while (Pad--)
@@ -442,6 +469,25 @@ Error llvm::writeArchive(StringRef ArcNa
if (!StringTableBuf.empty())
Data.insert(Data.begin(), computeStringTable(StringTableBuf));
+ // We would like to detect if we need to switch to a 64-bit symbol table.
+ if (WriteSymtab) {
+ uint64_t MaxOffset = 0;
+ uint64_t LastOffset = MaxOffset;
+ for (const auto& M : Data) {
+ // Record the start of the member's offset
+ LastOffset = MaxOffset;
+ // Account for the size of each part associated with the member.
+ MaxOffset += M.Header.size() + M.Data.size() + M.Padding.size();
+ // We assume 32-bit symbols to see if 32-bit symbols are possible or not.
+ MaxOffset += M.Symbols.size() * 4;
+ }
+ // If LastOffset isn't going to fit in a 32-bit varible we need to switch
+ // to 64-bit. Note that the file can be larger than 4GB as long as the last
+ // member starts before the 4GB offset.
+ if (LastOffset >> 32 != 0)
+ Kind = object::Archive::K_GNU64;
+ }
+
SmallString<128> TmpArchive;
int TmpArchiveFD;
if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
Added: llvm/trunk/test/Object/archive-SYM64-write.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Object/archive-SYM64-write.test?rev=316805&view=auto
==============================================================================
--- llvm/trunk/test/Object/archive-SYM64-write.test (added)
+++ llvm/trunk/test/Object/archive-SYM64-write.test Fri Oct 27 15:26:37 2017
@@ -0,0 +1,31 @@
+# RUN: yaml2obj %s > %t
+# RUN: rm -f %t.lib
+# RUN: cp %t %t2
+# RUN: llvm-ar cr %t.lib %t %t2 %p/Inputs/trivial-object-test.elf-x86-64
+# RUN: llvm-nm --print-armap %t.lib | FileCheck %s
+
+!ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_EXEC
+ Machine: EM_X86_64
+Sections:
+ - Name: .data
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC ]
+ AddressAlign: 0x0000000000000001
+ Content: "00"
+ Size: 2147483648
+
+# CHECK: Archive map
+# CHECK-NEXT: main in trivial-object-test.elf-x86-64
+
+# CHECK: archive-SYM64-write.test.tmp:
+
+# CHECK: archive-SYM64-write.test.tmp2:
+
+# CHECK: trivial-object-test.elf-x86-64:
+# CHECK-NEXT: U SomeOtherFunction
+# CHECK-NEXT: 0000000000000000 T main
+# CHECK-NEXT: U puts
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