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rust/src/rustllvm/PassWrapper.cpp
bors 4cb396c680 Auto merge of #41560 - alevy:rwpi-ropi, r=eddyb 
Add RWPI/ROPI relocation model support

This PR adds support for using LLVM 4's ROPI and RWPI relocation models for ARM.

ROPI (Read-Only Position Independence) and RWPI (Read-Write Position Independence) are two new relocation models in LLVM for the ARM backend ([LLVM changset](https://reviews.llvm.org/rL278015)). The motivation is that these are the specific strategies we use in userspace [Tock](https://www.tockos.org) apps, so supporting this is an important step (perhaps the final step, but can't confirm yet) in enabling userspace Rust processes.

## Explanation

ROPI makes all code and immutable accesses PC relative, but not assumed to be overriden at runtime (so for example, jumps are always relative).

RWPI uses a base register (`r9`) that stores the addresses of the GOT in memory so the runtime (e.g. a kernel) only adjusts r9 tell running code where the GOT is.

## Complications adding support in Rust

While this landed in LLVM master back in August, the header files in `llvm-c` have not been updated yet to reflect it. Rust replicates that header file's version of the `LLVMRelocMode` enum as the Rust enum `llvm::RelocMode` and uses an implicit cast in the ffi to translate from Rust's notion of the relocation model to the LLVM library's notion.

My workaround for this currently is to replace the `LLVMRelocMode` argument to `LLVMTargetMachineRef` with an int and using the hardcoded int representation of the `RelocMode` enum. This is A Bad Idea(tm), but I think very nearly the right thing.

Would a better alternative be to patch rust-llvm to support these enum variants (also a fairly trivial change)?
2017-05-01 17:23:09 +00:00

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// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#include <stdio.h>
#include "rustllvm.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/AutoUpgrade.h"
#include "llvm/Support/CBindingWrapping.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Host.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include "llvm/Transforms/IPO/PassManagerBuilder.h"
#if LLVM_VERSION_GE(4, 0)
#include "llvm/Transforms/IPO/AlwaysInliner.h"
#endif
#include "llvm-c/Transforms/PassManagerBuilder.h"
using namespace llvm;
using namespace llvm::legacy;
extern cl::opt<bool> EnableARMEHABI;
typedef struct LLVMOpaquePass *LLVMPassRef;
typedef struct LLVMOpaqueTargetMachine *LLVMTargetMachineRef;
DEFINE_STDCXX_CONVERSION_FUNCTIONS(Pass, LLVMPassRef)
DEFINE_STDCXX_CONVERSION_FUNCTIONS(TargetMachine, LLVMTargetMachineRef)
DEFINE_STDCXX_CONVERSION_FUNCTIONS(PassManagerBuilder,
LLVMPassManagerBuilderRef)
extern "C" void LLVMInitializePasses() {
PassRegistry &Registry = *PassRegistry::getPassRegistry();
initializeCore(Registry);
initializeCodeGen(Registry);
initializeScalarOpts(Registry);
initializeVectorization(Registry);
initializeIPO(Registry);
initializeAnalysis(Registry);
#if LLVM_VERSION_EQ(3, 7)
initializeIPA(Registry);
#endif
initializeTransformUtils(Registry);
initializeInstCombine(Registry);
initializeInstrumentation(Registry);
initializeTarget(Registry);
}
enum class LLVMRustPassKind {
Other,
Function,
Module,
};
static LLVMRustPassKind toRust(PassKind Kind) {
switch (Kind) {
case PT_Function:
return LLVMRustPassKind::Function;
case PT_Module:
return LLVMRustPassKind::Module;
default:
return LLVMRustPassKind::Other;
}
}
extern "C" LLVMPassRef LLVMRustFindAndCreatePass(const char *PassName) {
StringRef SR(PassName);
PassRegistry *PR = PassRegistry::getPassRegistry();
const PassInfo *PI = PR->getPassInfo(SR);
if (PI) {
return wrap(PI->createPass());
}
return nullptr;
}
extern "C" LLVMRustPassKind LLVMRustPassKind(LLVMPassRef RustPass) {
assert(RustPass);
Pass *Pass = unwrap(RustPass);
return toRust(Pass->getPassKind());
}
extern "C" void LLVMRustAddPass(LLVMPassManagerRef PMR, LLVMPassRef RustPass) {
assert(RustPass);
Pass *Pass = unwrap(RustPass);
PassManagerBase *PMB = unwrap(PMR);
PMB->add(Pass);
}
#ifdef LLVM_COMPONENT_X86
#define SUBTARGET_X86 SUBTARGET(X86)
#else
#define SUBTARGET_X86
#endif
#ifdef LLVM_COMPONENT_ARM
#define SUBTARGET_ARM SUBTARGET(ARM)
#else
#define SUBTARGET_ARM
#endif
#ifdef LLVM_COMPONENT_AARCH64
#define SUBTARGET_AARCH64 SUBTARGET(AArch64)
#else
#define SUBTARGET_AARCH64
#endif
#ifdef LLVM_COMPONENT_MIPS
#define SUBTARGET_MIPS SUBTARGET(Mips)
#else
#define SUBTARGET_MIPS
#endif
#ifdef LLVM_COMPONENT_POWERPC
#define SUBTARGET_PPC SUBTARGET(PPC)
#else
#define SUBTARGET_PPC
#endif
#ifdef LLVM_COMPONENT_SYSTEMZ
#define SUBTARGET_SYSTEMZ SUBTARGET(SystemZ)
#else
#define SUBTARGET_SYSTEMZ
#endif
#ifdef LLVM_COMPONENT_MSP430
#define SUBTARGET_MSP430 SUBTARGET(MSP430)
#else
#define SUBTARGET_MSP430
#endif
#ifdef LLVM_COMPONENT_SPARC
#define SUBTARGET_SPARC SUBTARGET(Sparc)
#else
#define SUBTARGET_SPARC
#endif
#ifdef LLVM_COMPONENT_HEXAGON
#define SUBTARGET_HEXAGON SUBTARGET(Hexagon)
#else
#define SUBTARGET_HEXAGON
#endif
#define GEN_SUBTARGETS \
SUBTARGET_X86 \
SUBTARGET_ARM \
SUBTARGET_AARCH64 \
SUBTARGET_MIPS \
SUBTARGET_PPC \
SUBTARGET_SYSTEMZ \
SUBTARGET_MSP430 \
SUBTARGET_SPARC \
SUBTARGET_HEXAGON
#define SUBTARGET(x) \
namespace llvm { \
extern const SubtargetFeatureKV x##FeatureKV[]; \
extern const SubtargetFeatureKV x##SubTypeKV[]; \
}
GEN_SUBTARGETS
#undef SUBTARGET
extern "C" bool LLVMRustHasFeature(LLVMTargetMachineRef TM,
const char *Feature) {
TargetMachine *Target = unwrap(TM);
const MCSubtargetInfo *MCInfo = Target->getMCSubtargetInfo();
const FeatureBitset &Bits = MCInfo->getFeatureBits();
const llvm::SubtargetFeatureKV *FeatureEntry;
#define SUBTARGET(x) \
if (MCInfo->isCPUStringValid(x##SubTypeKV[0].Key)) { \
FeatureEntry = x##FeatureKV; \
} else
GEN_SUBTARGETS { return false; }
#undef SUBTARGET
while (strcmp(Feature, FeatureEntry->Key) != 0)
FeatureEntry++;
return (Bits & FeatureEntry->Value) == FeatureEntry->Value;
}
enum class LLVMRustCodeModel {
Other,
Default,
JITDefault,
Small,
Kernel,
Medium,
Large,
};
static CodeModel::Model fromRust(LLVMRustCodeModel Model) {
switch (Model) {
case LLVMRustCodeModel::Default:
return CodeModel::Default;
case LLVMRustCodeModel::JITDefault:
return CodeModel::JITDefault;
case LLVMRustCodeModel::Small:
return CodeModel::Small;
case LLVMRustCodeModel::Kernel:
return CodeModel::Kernel;
case LLVMRustCodeModel::Medium:
return CodeModel::Medium;
case LLVMRustCodeModel::Large:
return CodeModel::Large;
default:
llvm_unreachable("Bad CodeModel.");
}
}
enum class LLVMRustCodeGenOptLevel {
Other,
None,
Less,
Default,
Aggressive,
};
static CodeGenOpt::Level fromRust(LLVMRustCodeGenOptLevel Level) {
switch (Level) {
case LLVMRustCodeGenOptLevel::None:
return CodeGenOpt::None;
case LLVMRustCodeGenOptLevel::Less:
return CodeGenOpt::Less;
case LLVMRustCodeGenOptLevel::Default:
return CodeGenOpt::Default;
case LLVMRustCodeGenOptLevel::Aggressive:
return CodeGenOpt::Aggressive;
default:
llvm_unreachable("Bad CodeGenOptLevel.");
}
}
enum class LLVMRustRelocMode {
Default,
Static,
PIC,
DynamicNoPic,
ROPI,
RWPI,
ROPIRWPI,
};
#if LLVM_VERSION_LE(3, 8)
static Reloc::Model fromRust(LLVMRustRelocMode RustReloc) {
#else
static Optional<Reloc::Model> fromRust(LLVMRustRelocMode RustReloc) {
#endif
switch (RustReloc) {
case LLVMRustRelocMode::Default:
#if LLVM_VERSION_LE(3, 8)
return Reloc::Default;
#else
return None;
#endif
case LLVMRustRelocMode::Static:
return Reloc::Static;
case LLVMRustRelocMode::PIC:
return Reloc::PIC_;
case LLVMRustRelocMode::DynamicNoPic:
return Reloc::DynamicNoPIC;
#if LLVM_VERSION_GE(4, 0)
case LLVMRustRelocMode::ROPI:
return Reloc::ROPI;
case LLVMRustRelocMode::RWPI:
return Reloc::RWPI;
case LLVMRustRelocMode::ROPIRWPI:
return Reloc::ROPI_RWPI;
#endif
default:
llvm_unreachable("Bad RelocModel.");
}
}
#if LLVM_RUSTLLVM
/// getLongestEntryLength - Return the length of the longest entry in the table.
///
static size_t getLongestEntryLength(ArrayRef<SubtargetFeatureKV> Table) {
size_t MaxLen = 0;
for (auto &I : Table)
MaxLen = std::max(MaxLen, std::strlen(I.Key));
return MaxLen;
}
extern "C" void LLVMRustPrintTargetCPUs(LLVMTargetMachineRef TM) {
const TargetMachine *Target = unwrap(TM);
const MCSubtargetInfo *MCInfo = Target->getMCSubtargetInfo();
const ArrayRef<SubtargetFeatureKV> CPUTable = MCInfo->getCPUTable();
unsigned MaxCPULen = getLongestEntryLength(CPUTable);
printf("Available CPUs for this target:\n");
for (auto &CPU : CPUTable)
printf(" %-*s - %s.\n", MaxCPULen, CPU.Key, CPU.Desc);
printf("\n");
}
extern "C" void LLVMRustPrintTargetFeatures(LLVMTargetMachineRef TM) {
const TargetMachine *Target = unwrap(TM);
const MCSubtargetInfo *MCInfo = Target->getMCSubtargetInfo();
const ArrayRef<SubtargetFeatureKV> FeatTable = MCInfo->getFeatureTable();
unsigned MaxFeatLen = getLongestEntryLength(FeatTable);
printf("Available features for this target:\n");
for (auto &Feature : FeatTable)
printf(" %-*s - %s.\n", MaxFeatLen, Feature.Key, Feature.Desc);
printf("\n");
printf("Use +feature to enable a feature, or -feature to disable it.\n"
"For example, rustc -C -target-cpu=mycpu -C "
"target-feature=+feature1,-feature2\n\n");
}
#else
extern "C" void LLVMRustPrintTargetCPUs(LLVMTargetMachineRef) {
printf("Target CPU help is not supported by this LLVM version.\n\n");
}
extern "C" void LLVMRustPrintTargetFeatures(LLVMTargetMachineRef) {
printf("Target features help is not supported by this LLVM version.\n\n");
}
#endif
extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
const char *TripleStr, const char *CPU, const char *Feature,
LLVMRustCodeModel RustCM, LLVMRustRelocMode RustReloc,
LLVMRustCodeGenOptLevel RustOptLevel, bool UseSoftFloat,
bool PositionIndependentExecutable, bool FunctionSections,
bool DataSections) {
auto CM = fromRust(RustCM);
auto OptLevel = fromRust(RustOptLevel);
auto RM = fromRust(RustReloc);
std::string Error;
Triple Trip(Triple::normalize(TripleStr));
const llvm::Target *TheTarget =
TargetRegistry::lookupTarget(Trip.getTriple(), Error);
if (TheTarget == nullptr) {
LLVMRustSetLastError(Error.c_str());
return nullptr;
}
StringRef RealCPU = CPU;
if (RealCPU == "native") {
RealCPU = sys::getHostCPUName();
}
TargetOptions Options;
#if LLVM_VERSION_LE(3, 8)
Options.PositionIndependentExecutable = PositionIndependentExecutable;
#endif
Options.FloatABIType = FloatABI::Default;
if (UseSoftFloat) {
Options.FloatABIType = FloatABI::Soft;
}
Options.DataSections = DataSections;
Options.FunctionSections = FunctionSections;
TargetMachine *TM = TheTarget->createTargetMachine(
Trip.getTriple(), RealCPU, Feature, Options, RM, CM, OptLevel);
return wrap(TM);
}
extern "C" void LLVMRustDisposeTargetMachine(LLVMTargetMachineRef TM) {
delete unwrap(TM);
}
// Unfortunately, LLVM doesn't expose a C API to add the corresponding analysis
// passes for a target to a pass manager. We export that functionality through
// this function.
extern "C" void LLVMRustAddAnalysisPasses(LLVMTargetMachineRef TM,
LLVMPassManagerRef PMR,
LLVMModuleRef M) {
PassManagerBase *PM = unwrap(PMR);
PM->add(
createTargetTransformInfoWrapperPass(unwrap(TM)->getTargetIRAnalysis()));
}
extern "C" void LLVMRustConfigurePassManagerBuilder(
LLVMPassManagerBuilderRef PMBR, LLVMRustCodeGenOptLevel OptLevel,
bool MergeFunctions, bool SLPVectorize, bool LoopVectorize) {
// Ignore mergefunc for now as enabling it causes crashes.
// unwrap(PMBR)->MergeFunctions = MergeFunctions;
unwrap(PMBR)->SLPVectorize = SLPVectorize;
unwrap(PMBR)->OptLevel = fromRust(OptLevel);
unwrap(PMBR)->LoopVectorize = LoopVectorize;
}
// Unfortunately, the LLVM C API doesn't provide a way to set the `LibraryInfo`
// field of a PassManagerBuilder, we expose our own method of doing so.
extern "C" void LLVMRustAddBuilderLibraryInfo(LLVMPassManagerBuilderRef PMBR,
LLVMModuleRef M,
bool DisableSimplifyLibCalls) {
Triple TargetTriple(unwrap(M)->getTargetTriple());
TargetLibraryInfoImpl *TLI = new TargetLibraryInfoImpl(TargetTriple);
if (DisableSimplifyLibCalls)
TLI->disableAllFunctions();
unwrap(PMBR)->LibraryInfo = TLI;
}
// Unfortunately, the LLVM C API doesn't provide a way to create the
// TargetLibraryInfo pass, so we use this method to do so.
extern "C" void LLVMRustAddLibraryInfo(LLVMPassManagerRef PMR, LLVMModuleRef M,
bool DisableSimplifyLibCalls) {
Triple TargetTriple(unwrap(M)->getTargetTriple());
TargetLibraryInfoImpl TLII(TargetTriple);
if (DisableSimplifyLibCalls)
TLII.disableAllFunctions();
unwrap(PMR)->add(new TargetLibraryInfoWrapperPass(TLII));
}
// Unfortunately, the LLVM C API doesn't provide an easy way of iterating over
// all the functions in a module, so we do that manually here. You'll find
// similar code in clang's BackendUtil.cpp file.
extern "C" void LLVMRustRunFunctionPassManager(LLVMPassManagerRef PMR,
LLVMModuleRef M) {
llvm::legacy::FunctionPassManager *P =
unwrap<llvm::legacy::FunctionPassManager>(PMR);
P->doInitialization();
// Upgrade all calls to old intrinsics first.
for (Module::iterator I = unwrap(M)->begin(), E = unwrap(M)->end(); I != E;)
UpgradeCallsToIntrinsic(&*I++); // must be post-increment, as we remove
for (Module::iterator I = unwrap(M)->begin(), E = unwrap(M)->end(); I != E;
++I)
if (!I->isDeclaration())
P->run(*I);
P->doFinalization();
}
extern "C" void LLVMRustSetLLVMOptions(int Argc, char **Argv) {
// Initializing the command-line options more than once is not allowed. So,
// check if they've already been initialized. (This could happen if we're
// being called from rustpkg, for example). If the arguments change, then
// that's just kinda unfortunate.
static bool Initialized = false;
if (Initialized)
return;
Initialized = true;
cl::ParseCommandLineOptions(Argc, Argv);
}
enum class LLVMRustFileType {
Other,
AssemblyFile,
ObjectFile,
};
static TargetMachine::CodeGenFileType fromRust(LLVMRustFileType Type) {
switch (Type) {
case LLVMRustFileType::AssemblyFile:
return TargetMachine::CGFT_AssemblyFile;
case LLVMRustFileType::ObjectFile:
return TargetMachine::CGFT_ObjectFile;
default:
llvm_unreachable("Bad FileType.");
}
}
extern "C" LLVMRustResult
LLVMRustWriteOutputFile(LLVMTargetMachineRef Target, LLVMPassManagerRef PMR,
LLVMModuleRef M, const char *Path,
LLVMRustFileType RustFileType) {
llvm::legacy::PassManager *PM = unwrap<llvm::legacy::PassManager>(PMR);
auto FileType = fromRust(RustFileType);
std::string ErrorInfo;
std::error_code EC;
raw_fd_ostream OS(Path, EC, sys::fs::F_None);
if (EC)
ErrorInfo = EC.message();
if (ErrorInfo != "") {
LLVMRustSetLastError(ErrorInfo.c_str());
return LLVMRustResult::Failure;
}
unwrap(Target)->addPassesToEmitFile(*PM, OS, FileType, false);
PM->run(*unwrap(M));
// Apparently `addPassesToEmitFile` adds a pointer to our on-the-stack output
// stream (OS), so the only real safe place to delete this is here? Don't we
// wish this was written in Rust?
delete PM;
return LLVMRustResult::Success;
}
extern "C" void LLVMRustPrintModule(LLVMPassManagerRef PMR, LLVMModuleRef M,
const char *Path) {
llvm::legacy::PassManager *PM = unwrap<llvm::legacy::PassManager>(PMR);
std::string ErrorInfo;
std::error_code EC;
raw_fd_ostream OS(Path, EC, sys::fs::F_None);
if (EC)
ErrorInfo = EC.message();
formatted_raw_ostream FOS(OS);
PM->add(createPrintModulePass(FOS));
PM->run(*unwrap(M));
}
extern "C" void LLVMRustPrintPasses() {
LLVMInitializePasses();
struct MyListener : PassRegistrationListener {
void passEnumerate(const PassInfo *Info) {
#if LLVM_VERSION_GE(4, 0)
StringRef PassArg = Info->getPassArgument();
StringRef PassName = Info->getPassName();
if (!PassArg.empty()) {
// These unsigned->signed casts could theoretically overflow, but
// realistically never will (and even if, the result is implementation
// defined rather plain UB).
printf("%15.*s - %.*s\n", (int)PassArg.size(), PassArg.data(),
(int)PassName.size(), PassName.data());
}
#else
if (Info->getPassArgument() && *Info->getPassArgument()) {
printf("%15s - %s\n", Info->getPassArgument(), Info->getPassName());
}
#endif
}
} Listener;
PassRegistry *PR = PassRegistry::getPassRegistry();
PR->enumerateWith(&Listener);
}
extern "C" void LLVMRustAddAlwaysInlinePass(LLVMPassManagerBuilderRef PMBR,
bool AddLifetimes) {
#if LLVM_VERSION_GE(4, 0)
unwrap(PMBR)->Inliner = llvm::createAlwaysInlinerLegacyPass(AddLifetimes);
#else
unwrap(PMBR)->Inliner = createAlwaysInlinerPass(AddLifetimes);
#endif
}
extern "C" void LLVMRustRunRestrictionPass(LLVMModuleRef M, char **Symbols,
size_t Len) {
llvm::legacy::PassManager passes;
#if LLVM_VERSION_LE(3, 8)
ArrayRef<const char *> Ref(Symbols, Len);
passes.add(llvm::createInternalizePass(Ref));
#else
auto PreserveFunctions = [=](const GlobalValue &GV) {
for (size_t I = 0; I < Len; I++) {
if (GV.getName() == Symbols[I]) {
return true;
}
}
return false;
};
passes.add(llvm::createInternalizePass(PreserveFunctions));
#endif
passes.run(*unwrap(M));
}
extern "C" void LLVMRustMarkAllFunctionsNounwind(LLVMModuleRef M) {
for (Module::iterator GV = unwrap(M)->begin(), E = unwrap(M)->end(); GV != E;
++GV) {
GV->setDoesNotThrow();
Function *F = dyn_cast<Function>(GV);
if (F == nullptr)
continue;
for (Function::iterator B = F->begin(), BE = F->end(); B != BE; ++B) {
for (BasicBlock::iterator I = B->begin(), IE = B->end(); I != IE; ++I) {
if (isa<InvokeInst>(I)) {
InvokeInst *CI = cast<InvokeInst>(I);
CI->setDoesNotThrow();
}
}
}
}
}
extern "C" void
LLVMRustSetDataLayoutFromTargetMachine(LLVMModuleRef Module,
LLVMTargetMachineRef TMR) {
TargetMachine *Target = unwrap(TMR);
unwrap(Module)->setDataLayout(Target->createDataLayout());
}
extern "C" LLVMTargetDataRef LLVMRustGetModuleDataLayout(LLVMModuleRef M) {
return wrap(&unwrap(M)->getDataLayout());
}
extern "C" void LLVMRustSetModulePIELevel(LLVMModuleRef M) {
#if LLVM_VERSION_GE(3, 9)
unwrap(M)->setPIELevel(PIELevel::Level::Large);
#endif
}
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