[llvm] r240304 - [FaultMaps] Add a parser for the __llvm__faultmaps section.
Ahmed Bougacha
ahmed.bougacha at gmail.com
Mon Jun 22 17:18:53 PDT 2015
On Mon, Jun 22, 2015 at 1:48 PM, Sanjoy Das
<sanjoy at playingwithpointers.com> wrote:
> Is it reasonable to put it under Object/ ? That's where SymbolRef is
> defined, for instance. Having said that, if this is a linking issue,
> why didn't the static build break?
Hmm, I just realized llvm-objdump/CMakeLists.txt actually has
${TARGETS_TO_BUILD} (duh), so it wouldn't be bad as I thought to
explicitly link with CodeGen.
As for why: I don't know much about the build system, but from what I
see, the static build explicitly links against libLLVMCodeGen.a (and,
in turn, all of each dependency's dependencies). The shared build
only has libLLVM<Target>CodeGen.so.
-Ahmed
> On Mon, Jun 22, 2015 at 1:31 PM, Ahmed Bougacha
> <ahmed.bougacha at gmail.com> wrote:
>> Hi Sanjoy,
>>
>> Seems like this broke my local shared libs build:
>>
>> Undefined symbols for architecture x86_64:
>> "llvm::operator<<(llvm::raw_ostream&, llvm::FaultMapParser const&)",
>> referenced from:
>> printFaultMaps(llvm::object::ObjectFile const*) in llvm-objdump.cpp.o
>>
>>
>> It's easily fixable by having llvm-objdump link with CodeGen, but I'm
>> not sure that's reasonable. Is there a better location for this code?
>>
>> -Ahmed
>>
>>
>> On Mon, Jun 22, 2015 at 11:03 AM, Sanjoy Das
>> <sanjoy at playingwithpointers.com> wrote:
>>> Author: sanjoy
>>> Date: Mon Jun 22 13:03:02 2015
>>> New Revision: 240304
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=240304&view=rev
>>> Log:
>>> [FaultMaps] Add a parser for the __llvm__faultmaps section.
>>>
>>> Summary:
>>> The parser is exercised by llvm-objdump using -print-fault-maps. As is
>>> probably obvious, the code itself was "heavily inspired" by
>>> http://reviews.llvm.org/D10434.
>>>
>>> Reviewers: reames, atrick, JosephTremoulet
>>>
>>> Subscribers: llvm-commits
>>>
>>> Differential Revision: http://reviews.llvm.org/D10491
>>>
>>> Added:
>>> llvm/trunk/test/MC/X86/faultmap-section-parsing.s
>>> Modified:
>>> llvm/trunk/include/llvm/CodeGen/FaultMaps.h
>>> llvm/trunk/lib/CodeGen/FaultMaps.cpp
>>> llvm/trunk/test/CodeGen/X86/implicit-null-check.ll
>>> llvm/trunk/tools/llvm-objdump/llvm-objdump.cpp
>>>
>>> Modified: llvm/trunk/include/llvm/CodeGen/FaultMaps.h
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/FaultMaps.h?rev=240304&r1=240303&r2=240304&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/include/llvm/CodeGen/FaultMaps.h (original)
>>> +++ llvm/trunk/include/llvm/CodeGen/FaultMaps.h Mon Jun 22 13:03:02 2015
>>> @@ -12,6 +12,8 @@
>>>
>>> #include "llvm/ADT/DenseMap.h"
>>> #include "llvm/MC/MCSymbol.h"
>>> +#include "llvm/Support/Endian.h"
>>> +#include "llvm/Support/Format.h"
>>>
>>> #include <vector>
>>> #include <map>
>>> @@ -68,6 +70,152 @@ private:
>>>
>>> void emitFunctionInfo(const MCSymbol *FnLabel, const FunctionFaultInfos &FFI);
>>> };
>>> +
>>> +/// A parser for the __llvm_faultmaps section generated by the FaultMaps class
>>> +/// above. This parser is version locked with with the __llvm_faultmaps section
>>> +/// generated by the version of LLVM that includes it. No guarantees are made
>>> +/// with respect to forward or backward compatibility.
>>> +class FaultMapParser {
>>> + typedef uint8_t FaultMapVersionType;
>>> + static const size_t FaultMapVersionOffset = 0;
>>> +
>>> + typedef uint8_t Reserved0Type;
>>> + static const size_t Reserved0Offset =
>>> + FaultMapVersionOffset + sizeof(FaultMapVersionType);
>>> +
>>> + typedef uint16_t Reserved1Type;
>>> + static const size_t Reserved1Offset = Reserved0Offset + sizeof(Reserved0Type);
>>> +
>>> + typedef uint32_t NumFunctionsType;
>>> + static const size_t NumFunctionsOffset =
>>> + Reserved1Offset + sizeof(Reserved1Type);
>>> +
>>> + static const size_t FunctionInfosOffset =
>>> + NumFunctionsOffset + sizeof(NumFunctionsType);
>>> +
>>> + const uint8_t *P;
>>> + const uint8_t *E;
>>> +
>>> + template <typename T> static T read(const uint8_t *P, const uint8_t *E) {
>>> + assert(P + sizeof(T) <= E && "out of bounds read!");
>>> + return support::endian::read<T, support::little, 1>(P);
>>> + }
>>> +
>>> +public:
>>> + class FunctionFaultInfoAccessor {
>>> + typedef uint32_t FaultKindType;
>>> + static const size_t FaultKindOffset = 0;
>>> +
>>> + typedef uint32_t FaultingPCOffsetType;
>>> + static const size_t FaultingPCOffsetOffset =
>>> + FaultKindOffset + sizeof(FaultKindType);
>>> +
>>> + typedef uint32_t HandlerPCOffsetType;
>>> + static const size_t HandlerPCOffsetOffset =
>>> + FaultingPCOffsetOffset + sizeof(FaultingPCOffsetType);
>>> +
>>> + const uint8_t *P;
>>> + const uint8_t *E;
>>> +
>>> + public:
>>> + static const size_t Size =
>>> + HandlerPCOffsetOffset + sizeof(HandlerPCOffsetType);
>>> +
>>> + explicit FunctionFaultInfoAccessor(const uint8_t *P, const uint8_t *E)
>>> + : P(P), E(E) {}
>>> +
>>> + FaultKindType getFaultKind() const {
>>> + return read<FaultKindType>(P + FaultKindOffset, E);
>>> + }
>>> +
>>> + FaultingPCOffsetType getFaultingPCOffset() const {
>>> + return read<FaultingPCOffsetType>(P + FaultingPCOffsetOffset, E);
>>> + }
>>> +
>>> + HandlerPCOffsetType getHandlerPCOffset() const {
>>> + return read<HandlerPCOffsetType>(P + HandlerPCOffsetOffset, E);
>>> + }
>>> + };
>>> +
>>> + class FunctionInfoAccessor {
>>> + typedef uint64_t FunctionAddrType;
>>> + static const size_t FunctionAddrOffset = 0;
>>> +
>>> + typedef uint32_t NumFaultingPCsType;
>>> + static const size_t NumFaultingPCsOffset =
>>> + FunctionAddrOffset + sizeof(FunctionAddrType);
>>> +
>>> + typedef uint32_t ReservedType;
>>> + static const size_t ReservedOffset =
>>> + NumFaultingPCsOffset + sizeof(NumFaultingPCsType);
>>> +
>>> + static const size_t FunctionFaultInfosOffset =
>>> + ReservedOffset + sizeof(ReservedType);
>>> +
>>> + static const size_t FunctionInfoHeaderSize = FunctionFaultInfosOffset;
>>> +
>>> + const uint8_t *P;
>>> + const uint8_t *E;
>>> +
>>> + public:
>>> + FunctionInfoAccessor() : P(nullptr), E(nullptr) {}
>>> +
>>> + explicit FunctionInfoAccessor(const uint8_t *P, const uint8_t *E)
>>> + : P(P), E(E) {}
>>> +
>>> + FunctionAddrType getFunctionAddr() const {
>>> + return read<FunctionAddrType>(P + FunctionAddrOffset, E);
>>> + }
>>> +
>>> + NumFaultingPCsType getNumFaultingPCs() const {
>>> + return read<NumFaultingPCsType>(P + NumFaultingPCsOffset, E);
>>> + }
>>> +
>>> + FunctionFaultInfoAccessor getFunctionFaultInfoAt(uint32_t Index) const {
>>> + assert(Index < getNumFaultingPCs() && "index out of bounds!");
>>> + const uint8_t *Begin = P + FunctionFaultInfosOffset +
>>> + FunctionFaultInfoAccessor::Size * Index;
>>> + return FunctionFaultInfoAccessor(Begin, E);
>>> + }
>>> +
>>> + FunctionInfoAccessor getNextFunctionInfo() const {
>>> + size_t MySize = FunctionInfoHeaderSize +
>>> + getNumFaultingPCs() * FunctionFaultInfoAccessor::Size;
>>> +
>>> + const uint8_t *Begin = P + MySize;
>>> + assert(Begin < E && "out of bounds!");
>>> + return FunctionInfoAccessor(Begin, E);
>>> + }
>>> + };
>>> +
>>> + explicit FaultMapParser(const uint8_t *Begin, const uint8_t *End)
>>> + : P(Begin), E(End) {}
>>> +
>>> + FaultMapVersionType getFaultMapVersion() const {
>>> + auto Version = read<FaultMapVersionType>(P + FaultMapVersionOffset, E);
>>> + assert(Version == 1 && "only version 1 supported!");
>>> + return Version;
>>> + }
>>> +
>>> + NumFunctionsType getNumFunctions() const {
>>> + return read<NumFunctionsType>(P + NumFunctionsOffset, E);
>>> + }
>>> +
>>> + FunctionInfoAccessor getFirstFunctionInfo() const {
>>> + const uint8_t *Begin = P + FunctionInfosOffset;
>>> + return FunctionInfoAccessor(Begin, E);
>>> + }
>>> +};
>>> +
>>> +raw_ostream &
>>> +operator<<(raw_ostream &OS,
>>> + const typename FaultMapParser::FunctionFaultInfoAccessor &);
>>> +
>>> +raw_ostream &operator<<(raw_ostream &OS,
>>> + const typename FaultMapParser::FunctionInfoAccessor &);
>>> +
>>> +raw_ostream &operator<<(raw_ostream &OS, const FaultMapParser &);
>>> +
>>> } // namespace llvm
>>>
>>> #endif
>>>
>>> Modified: llvm/trunk/lib/CodeGen/FaultMaps.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/FaultMaps.cpp?rev=240304&r1=240303&r2=240304&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/lib/CodeGen/FaultMaps.cpp (original)
>>> +++ llvm/trunk/lib/CodeGen/FaultMaps.cpp Mon Jun 22 13:03:02 2015
>>> @@ -112,3 +112,40 @@ const char *FaultMaps::faultTypeToString
>>> return "FaultingLoad";
>>> }
>>> }
>>> +
>>> +raw_ostream &llvm::
>>> +operator<<(raw_ostream &OS,
>>> + const typename FaultMapParser::FunctionFaultInfoAccessor &FFI) {
>>> + OS << "Fault kind: "
>>> + << FaultMaps::faultTypeToString((FaultMaps::FaultKind)FFI.getFaultKind())
>>> + << ", faulting PC offset: " << FFI.getFaultingPCOffset()
>>> + << ", handling PC offset: " << FFI.getHandlerPCOffset();
>>> + return OS;
>>> +}
>>> +
>>> +raw_ostream &llvm::
>>> +operator<<(raw_ostream &OS,
>>> + const typename FaultMapParser::FunctionInfoAccessor &FI) {
>>> + OS << "FunctionAddress: " << format_hex(FI.getFunctionAddr(), 8)
>>> + << ", NumFaultingPCs: " << FI.getNumFaultingPCs() << "\n";
>>> + for (unsigned i = 0, e = FI.getNumFaultingPCs(); i != e; ++i)
>>> + OS << FI.getFunctionFaultInfoAt(i) << "\n";
>>> + return OS;
>>> +}
>>> +
>>> +raw_ostream &llvm::operator<<(raw_ostream &OS, const FaultMapParser &FMP) {
>>> + OS << "Version: " << format_hex(FMP.getFaultMapVersion(), 2) << "\n";
>>> + OS << "NumFunctions: " << FMP.getNumFunctions() << "\n";
>>> +
>>> + if (FMP.getNumFunctions() == 0)
>>> + return OS;
>>> +
>>> + typename FaultMapParser::FunctionInfoAccessor FI;
>>> +
>>> + for (unsigned i = 0, e = FMP.getNumFunctions(); i != e; ++i) {
>>> + FI = (i == 0) ? FMP.getFirstFunctionInfo() : FI.getNextFunctionInfo();
>>> + OS << FI;
>>> + }
>>> +
>>> + return OS;
>>> +}
>>>
>>> Modified: llvm/trunk/test/CodeGen/X86/implicit-null-check.ll
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/implicit-null-check.ll?rev=240304&r1=240303&r2=240304&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/test/CodeGen/X86/implicit-null-check.ll (original)
>>> +++ llvm/trunk/test/CodeGen/X86/implicit-null-check.ll Mon Jun 22 13:03:02 2015
>>> @@ -1,5 +1,15 @@
>>> ; RUN: llc -O3 -mtriple=x86_64-apple-macosx -enable-implicit-null-checks < %s | FileCheck %s
>>>
>>> +; RUN: llc < %s -mtriple=x86_64-apple-macosx -enable-implicit-null-checks \
>>> +; RUN: | llvm-mc -triple x86_64-apple-macosx -filetype=obj -o - \
>>> +; RUN: | llvm-objdump -triple x86_64-apple-macosx -fault-map-section - \
>>> +; RUN: | FileCheck %s -check-prefix OBJDUMP
>>> +
>>> +; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -enable-implicit-null-checks \
>>> +; RUN: | llvm-mc -triple x86_64-unknown-linux-gnu -filetype=obj -o - \
>>> +; RUN: | llvm-objdump -triple x86_64-unknown-linux-gnu -fault-map-section - \
>>> +; RUN: | FileCheck %s -check-prefix OBJDUMP
>>> +
>>> define i32 @imp_null_check_load(i32* %x) {
>>> ; CHECK-LABEL: _imp_null_check_load:
>>> ; CHECK: Ltmp1:
>>> @@ -116,3 +126,13 @@ define i32 @imp_null_check_add_result(i3
>>> ; CHECK-NEXT: .long Ltmp1-_imp_null_check_load
>>> ; Fault[0].HandlerOffset:
>>> ; CHECK-NEXT: .long Ltmp0-_imp_null_check_load
>>> +
>>> +; OBJDUMP: FaultMap table:
>>> +; OBJDUMP-NEXT: Version: 0x1
>>> +; OBJDUMP-NEXT: NumFunctions: 3
>>> +; OBJDUMP-NEXT: FunctionAddress: 0x000000, NumFaultingPCs: 1
>>> +; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 5
>>> +; OBJDUMP-NEXT: FunctionAddress: 0x000000, NumFaultingPCs: 1
>>> +; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 7
>>> +; OBJDUMP-NEXT: FunctionAddress: 0x000000, NumFaultingPCs: 1
>>> +; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 3
>>>
>>> Added: llvm/trunk/test/MC/X86/faultmap-section-parsing.s
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/X86/faultmap-section-parsing.s?rev=240304&view=auto
>>> ==============================================================================
>>> --- llvm/trunk/test/MC/X86/faultmap-section-parsing.s (added)
>>> +++ llvm/trunk/test/MC/X86/faultmap-section-parsing.s Mon Jun 22 13:03:02 2015
>>> @@ -0,0 +1,29 @@
>>> +// RUN: llvm-mc < %s -triple=x86_64-apple-macosx -filetype=obj -o - | llvm-objdump -fault-map-section - | FileCheck %s
>>> +
>>> + .section __LLVM_FAULTMAPS,__llvm_faultmaps
>>> +__LLVM_FaultMaps:
>>> + .byte 1
>>> + .byte 0
>>> + .short 0
>>> + .long 2
>>> + .quad 0xFFDEAD
>>> + .long 1
>>> + .long 0
>>> + .long 1
>>> + .long 100
>>> + .long 200
>>> +
>>> + .quad 0xFFDAED
>>> + .long 1
>>> + .long 0
>>> + .long 1
>>> + .long 400
>>> + .long 500
>>> +
>>> +// CHECK: FaultMap table:
>>> +// CHECK-NEXT: Version: 0x1
>>> +// CHECK-NEXT: NumFunctions: 2
>>> +// CHECK-NEXT: FunctionAddress: 0xffdead, NumFaultingPCs: 1
>>> +// CHECK-NEXT: Fault kind: FaultingLoad, faulting PC offset: 100, handling PC offset: 200
>>> +// CHECK-NEXT: FunctionAddress: 0xffdaed, NumFaultingPCs: 1
>>> +// CHECK-NEXT: Fault kind: FaultingLoad, faulting PC offset: 400, handling PC offset: 500
>>>
>>> Modified: llvm/trunk/tools/llvm-objdump/llvm-objdump.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objdump/llvm-objdump.cpp?rev=240304&r1=240303&r2=240304&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/tools/llvm-objdump/llvm-objdump.cpp (original)
>>> +++ llvm/trunk/tools/llvm-objdump/llvm-objdump.cpp Mon Jun 22 13:03:02 2015
>>> @@ -17,9 +17,11 @@
>>> //===----------------------------------------------------------------------===//
>>>
>>> #include "llvm-objdump.h"
>>> +#include "llvm/ADT/Optional.h"
>>> #include "llvm/ADT/STLExtras.h"
>>> #include "llvm/ADT/StringExtras.h"
>>> #include "llvm/ADT/Triple.h"
>>> +#include "llvm/CodeGen/FaultMaps.h"
>>> #include "llvm/MC/MCAsmInfo.h"
>>> #include "llvm/MC/MCContext.h"
>>> #include "llvm/MC/MCDisassembler.h"
>>> @@ -153,6 +155,9 @@ cl::opt<bool>
>>> llvm::PrintImmHex("print-imm-hex",
>>> cl::desc("Use hex format for immediate values"));
>>>
>>> +cl::opt<bool> PrintFaultMaps("fault-map-section",
>>> + cl::desc("Display contents of faultmap section"));
>>> +
>>> static StringRef ToolName;
>>> static int ReturnValue = EXIT_SUCCESS;
>>>
>>> @@ -1226,6 +1231,49 @@ void llvm::printWeakBindTable(const Obje
>>> }
>>> }
>>>
>>> +static void printFaultMaps(const ObjectFile *Obj) {
>>> + const char *FaultMapSectionName = nullptr;
>>> +
>>> + if (isa<ELFObjectFileBase>(Obj)) {
>>> + FaultMapSectionName = ".llvm_faultmaps";
>>> + } else if (isa<MachOObjectFile>(Obj)) {
>>> + FaultMapSectionName = "__llvm_faultmaps";
>>> + } else {
>>> + errs() << "This operation is only currently supported "
>>> + "for ELF and Mach-O executable files.\n";
>>> + return;
>>> + }
>>> +
>>> + Optional<object::SectionRef> FaultMapSection;
>>> +
>>> + for (auto Sec : Obj->sections()) {
>>> + StringRef Name;
>>> + Sec.getName(Name);
>>> + if (Name == FaultMapSectionName) {
>>> + FaultMapSection = Sec;
>>> + break;
>>> + }
>>> + }
>>> +
>>> + outs() << "FaultMap table:\n";
>>> +
>>> + if (!FaultMapSection.hasValue()) {
>>> + outs() << "<not found>\n";
>>> + return;
>>> + }
>>> +
>>> + StringRef FaultMapContents;
>>> + if (error(FaultMapSection.getValue().getContents(FaultMapContents))) {
>>> + errs() << "Could not read the " << FaultMapContents << " section!\n";
>>> + return;
>>> + }
>>> +
>>> + FaultMapParser FMP(FaultMapContents.bytes_begin(),
>>> + FaultMapContents.bytes_end());
>>> +
>>> + outs() << FMP;
>>> +}
>>> +
>>> static void printPrivateFileHeader(const ObjectFile *o) {
>>> if (o->isELF()) {
>>> printELFFileHeader(o);
>>> @@ -1265,6 +1313,8 @@ static void DumpObject(const ObjectFile
>>> printLazyBindTable(o);
>>> if (WeakBind)
>>> printWeakBindTable(o);
>>> + if (PrintFaultMaps)
>>> + printFaultMaps(o);
>>> }
>>>
>>> /// @brief Dump each object file in \a a;
>>> @@ -1362,7 +1412,8 @@ int main(int argc, char **argv) {
>>> && !(DylibsUsed && MachOOpt)
>>> && !(DylibId && MachOOpt)
>>> && !(ObjcMetaData && MachOOpt)
>>> - && !(DumpSections.size() != 0 && MachOOpt)) {
>>> + && !(DumpSections.size() != 0 && MachOOpt)
>>> + && !PrintFaultMaps) {
>>> cl::PrintHelpMessage();
>>> return 2;
>>> }
>>>
>>>
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