[llvm] r240304 - [FaultMaps] Add a parser for the __llvm__faultmaps section.
Sanjoy Das
sanjoy at playingwithpointers.com
Mon Jun 22 13:48:06 PDT 2015
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?
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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