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      1 /*
      2  * Copyright 2010-2012, The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *     http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "Assert.h"
     18 #include "Log.h"
     19 #include "RSTransforms.h"
     20 #include "RSUtils.h"
     21 #include "rsDefines.h"
     22 
     23 #include "bcc/Compiler.h"
     24 #include "bcc/CompilerConfig.h"
     25 #include "bcc/Config.h"
     26 #include "bcc/Script.h"
     27 #include "bcc/Source.h"
     28 #include "bcinfo/MetadataExtractor.h"
     29 
     30 #include <llvm/Analysis/Passes.h>
     31 #include <llvm/Analysis/TargetTransformInfo.h>
     32 #include <llvm/CodeGen/RegAllocRegistry.h>
     33 #include <llvm/IR/LegacyPassManager.h>
     34 #include <llvm/IR/Module.h>
     35 #include <llvm/Support/TargetRegistry.h>
     36 #include <llvm/Support/raw_ostream.h>
     37 #include <llvm/IR/DataLayout.h>
     38 #include <llvm/Target/TargetSubtargetInfo.h>
     39 #include <llvm/Target/TargetMachine.h>
     40 #include <llvm/Transforms/IPO.h>
     41 #include <llvm/Transforms/IPO/PassManagerBuilder.h>
     42 #include <llvm/Transforms/Scalar.h>
     43 #include <llvm/Transforms/Vectorize.h>
     44 
     45 #include <string>
     46 #include <set>
     47 
     48 namespace {
     49 
     50 // Name of metadata node where list of exported types resides
     51 // (should be synced with slang_rs_metadata.h)
     52 static const llvm::StringRef ExportedTypeMetadataName = "#rs_export_type";
     53 
     54 // Every exported struct type must have the same layout according to
     55 // the Module's DataLayout that it does according to the
     56 // TargetMachine's DataLayout -- that is, the front end (represented
     57 // by Module) and back end (represented by TargetMachine) must agree.
     58 bool validateLayoutOfExportedTypes(const llvm::Module &module,
     59                                    const llvm::DataLayout &moduleDataLayout,
     60                                    const llvm::DataLayout &targetDataLayout) {
     61   if (moduleDataLayout == targetDataLayout)
     62     return true;
     63 
     64   const llvm::NamedMDNode *const exportedTypesMD =
     65       module.getNamedMetadata(ExportedTypeMetadataName);
     66   if (!exportedTypesMD)
     67     return true;
     68 
     69   bool allOk = true;
     70   for (const llvm::MDNode *const exportedTypeMD : exportedTypesMD->operands()) {
     71     bccAssert(exportedTypeMD->getNumOperands() == 1);
     72 
     73     // The name of the type in LLVM is the name of the type in the
     74     // metadata with "struct." prepended.
     75     std::string exportedTypeName =
     76         "struct." +
     77         llvm::cast<llvm::MDString>(exportedTypeMD->getOperand(0))->getString().str();
     78 
     79     llvm::StructType *const exportedType = module.getTypeByName(exportedTypeName);
     80 
     81     if (!exportedType) {
     82       // presumably this means the type got optimized away
     83       continue;
     84     }
     85 
     86     const llvm::StructLayout *const moduleStructLayout = moduleDataLayout.getStructLayout(exportedType);
     87     const llvm::StructLayout *const targetStructLayout = targetDataLayout.getStructLayout(exportedType);
     88 
     89     if (moduleStructLayout->getSizeInBits() != targetStructLayout->getSizeInBits()) {
     90       ALOGE("%s: getSizeInBits() does not match (%u, %u)", exportedTypeName.c_str(),
     91             unsigned(moduleStructLayout->getSizeInBits()), unsigned(targetStructLayout->getSizeInBits()));
     92       allOk = false;
     93     }
     94 
     95     // We deliberately do not check alignment of the struct as a whole -- the explicit padding
     96     // from slang doesn't force the alignment.
     97 
     98     for (unsigned elementCount = exportedType->getNumElements(), elementIdx = 0;
     99          elementIdx < elementCount; ++elementIdx) {
    100       if (moduleStructLayout->getElementOffsetInBits(elementIdx) !=
    101           targetStructLayout->getElementOffsetInBits(elementIdx)) {
    102         ALOGE("%s: getElementOffsetInBits(%u) does not match (%u, %u)",
    103               exportedTypeName.c_str(), elementIdx,
    104               unsigned(moduleStructLayout->getElementOffsetInBits(elementIdx)),
    105               unsigned(targetStructLayout->getElementOffsetInBits(elementIdx)));
    106         allOk = false;
    107       }
    108     }
    109   }
    110 
    111   return allOk;
    112 }
    113 
    114 }  // end unnamed namespace
    115 
    116 using namespace bcc;
    117 
    118 const char *Compiler::GetErrorString(enum ErrorCode pErrCode) {
    119   switch (pErrCode) {
    120   case kSuccess:
    121     return "Successfully compiled.";
    122   case kInvalidConfigNoTarget:
    123     return "Invalid compiler config supplied (getTarget() returns nullptr.) "
    124            "(missing call to CompilerConfig::initialize()?)";
    125   case kErrCreateTargetMachine:
    126     return "Failed to create llvm::TargetMachine.";
    127   case kErrSwitchTargetMachine:
    128     return  "Failed to switch llvm::TargetMachine.";
    129   case kErrNoTargetMachine:
    130     return "Failed to compile the script since there's no available "
    131            "TargetMachine. (missing call to Compiler::config()?)";
    132   case kErrMaterialization:
    133     return "Failed to materialize the module.";
    134   case kErrInvalidOutputFileState:
    135     return "Supplied output file was invalid (in the error state.)";
    136   case kErrPrepareOutput:
    137     return "Failed to prepare file for output.";
    138   case kPrepareCodeGenPass:
    139     return "Failed to construct pass list for code-generation.";
    140   case kErrCustomPasses:
    141     return "Error occurred while adding custom passes.";
    142   case kErrInvalidSource:
    143     return "Error loading input bitcode";
    144   case kIllegalGlobalFunction:
    145     return "Use of undefined external function";
    146   case kErrInvalidTargetMachine:
    147     return "Invalid/unexpected llvm::TargetMachine.";
    148   case kErrInvalidLayout:
    149     return "Invalid layout (RenderScript ABI and native ABI are incompatible)";
    150   }
    151 
    152   // This assert should never be reached as the compiler verifies that the
    153   // above switch coveres all enum values.
    154   bccAssert(false && "Unknown error code encountered");
    155   return  "";
    156 }
    157 
    158 //===----------------------------------------------------------------------===//
    159 // Instance Methods
    160 //===----------------------------------------------------------------------===//
    161 Compiler::Compiler() : mTarget(nullptr), mEnableOpt(true) {
    162   return;
    163 }
    164 
    165 Compiler::Compiler(const CompilerConfig &pConfig) : mTarget(nullptr),
    166                                                     mEnableOpt(true) {
    167   const std::string &triple = pConfig.getTriple();
    168 
    169   enum ErrorCode err = config(pConfig);
    170   if (err != kSuccess) {
    171     ALOGE("%s (%s, features: %s)", GetErrorString(err),
    172           triple.c_str(), pConfig.getFeatureString().c_str());
    173     return;
    174   }
    175 
    176   return;
    177 }
    178 
    179 enum Compiler::ErrorCode Compiler::config(const CompilerConfig &pConfig) {
    180   if (pConfig.getTarget() == nullptr) {
    181     return kInvalidConfigNoTarget;
    182   }
    183 
    184   llvm::TargetMachine *new_target =
    185       (pConfig.getTarget())->createTargetMachine(pConfig.getTriple(),
    186                                                  pConfig.getCPU(),
    187                                                  pConfig.getFeatureString(),
    188                                                  pConfig.getTargetOptions(),
    189                                                  pConfig.getRelocationModel(),
    190                                                  pConfig.getCodeModel(),
    191                                                  pConfig.getOptimizationLevel());
    192 
    193   if (new_target == nullptr) {
    194     return ((mTarget != nullptr) ? kErrSwitchTargetMachine :
    195                                    kErrCreateTargetMachine);
    196   }
    197 
    198   // Replace the old TargetMachine.
    199   delete mTarget;
    200   mTarget = new_target;
    201 
    202   // Adjust register allocation policy according to the optimization level.
    203   //  createFastRegisterAllocator: fast but bad quality
    204   //  createLinearScanRegisterAllocator: not so fast but good quality
    205   if ((pConfig.getOptimizationLevel() == llvm::CodeGenOpt::None)) {
    206     llvm::RegisterRegAlloc::setDefault(llvm::createFastRegisterAllocator);
    207   } else {
    208     llvm::RegisterRegAlloc::setDefault(llvm::createGreedyRegisterAllocator);
    209   }
    210 
    211   return kSuccess;
    212 }
    213 
    214 Compiler::~Compiler() {
    215   delete mTarget;
    216 }
    217 
    218 
    219 // This function has complete responsibility for creating and executing the
    220 // exact list of compiler passes.
    221 enum Compiler::ErrorCode Compiler::runPasses(Script &script,
    222                                              llvm::raw_pwrite_stream &pResult) {
    223   // Pass manager for link-time optimization
    224   llvm::legacy::PassManager transformPasses;
    225 
    226   // Empty MCContext.
    227   llvm::MCContext *mc_context = nullptr;
    228 
    229   transformPasses.add(
    230       createTargetTransformInfoWrapperPass(mTarget->getTargetIRAnalysis()));
    231 
    232   // Add some initial custom passes.
    233   addInvokeHelperPass(transformPasses);
    234   addExpandKernelPass(transformPasses);
    235   addDebugInfoPass(script, transformPasses);
    236   addInvariantPass(transformPasses);
    237   if (mTarget->getOptLevel() != llvm::CodeGenOpt::None) {
    238     if (!addInternalizeSymbolsPass(script, transformPasses))
    239       return kErrCustomPasses;
    240   }
    241   addGlobalInfoPass(script, transformPasses);
    242 
    243   if (mTarget->getOptLevel() == llvm::CodeGenOpt::None) {
    244     transformPasses.add(llvm::createGlobalOptimizerPass());
    245     transformPasses.add(llvm::createConstantMergePass());
    246 
    247   } else {
    248     // FIXME: Figure out which passes should be executed.
    249     llvm::PassManagerBuilder Builder;
    250     Builder.Inliner = llvm::createFunctionInliningPass();
    251     Builder.populateLTOPassManager(transformPasses);
    252 
    253     /* FIXME: Reenable autovectorization after rebase.
    254        bug 19324423
    255     // Add vectorization passes after LTO passes are in
    256     // additional flag: -unroll-runtime
    257     transformPasses.add(llvm::createLoopUnrollPass(-1, 16, 0, 1));
    258     // Need to pass appropriate flags here: -scalarize-load-store
    259     transformPasses.add(llvm::createScalarizerPass());
    260     transformPasses.add(llvm::createCFGSimplificationPass());
    261     transformPasses.add(llvm::createScopedNoAliasAAPass());
    262     transformPasses.add(llvm::createScalarEvolutionAliasAnalysisPass());
    263     // additional flags: -slp-vectorize-hor -slp-vectorize-hor-store (unnecessary?)
    264     transformPasses.add(llvm::createSLPVectorizerPass());
    265     transformPasses.add(llvm::createDeadCodeEliminationPass());
    266     transformPasses.add(llvm::createInstructionCombiningPass());
    267     */
    268   }
    269 
    270   // These passes have to come after LTO, since we don't want to examine
    271   // functions that are never actually called.
    272   if (llvm::Triple(getTargetMachine().getTargetTriple()).getArch() == llvm::Triple::x86_64 ||
    273       llvm::Triple(getTargetMachine().getTargetTriple()).getArch() == llvm::Triple::mips64el)
    274     transformPasses.add(createRSX86_64CallConvPass());  // Add pass to correct calling convention for X86-64 and mips64.
    275   transformPasses.add(createRSIsThreadablePass());      // Add pass to mark script as threadable.
    276 
    277   // RSEmbedInfoPass needs to come after we have scanned for non-threadable
    278   // functions.
    279   if (script.getEmbedInfo())
    280     transformPasses.add(createRSEmbedInfoPass());
    281 
    282   // Execute the passes.
    283   transformPasses.run(script.getSource().getModule());
    284 
    285   // Run backend separately to avoid interference between debug metadata
    286   // generation and backend initialization.
    287   llvm::legacy::PassManager codeGenPasses;
    288 
    289   // Add passes to the pass manager to emit machine code through MC layer.
    290   if (mTarget->addPassesToEmitMC(codeGenPasses, mc_context, pResult,
    291                                  /* DisableVerify */false)) {
    292     return kPrepareCodeGenPass;
    293   }
    294 
    295   // Execute the passes.
    296   codeGenPasses.run(script.getSource().getModule());
    297 
    298   return kSuccess;
    299 }
    300 
    301 enum Compiler::ErrorCode Compiler::compile(Script &script,
    302                                            llvm::raw_pwrite_stream &pResult,
    303                                            llvm::raw_ostream *IRStream) {
    304   llvm::Module &module = script.getSource().getModule();
    305   enum ErrorCode err;
    306 
    307   if (mTarget == nullptr) {
    308     return kErrNoTargetMachine;
    309   }
    310 
    311   const std::string &triple = module.getTargetTriple();
    312   const llvm::DataLayout dl = getTargetMachine().createDataLayout();
    313   unsigned int pointerSize = dl.getPointerSizeInBits();
    314   if (triple == "armv7-none-linux-gnueabi") {
    315     if (pointerSize != 32) {
    316       return kErrInvalidSource;
    317     }
    318   } else if (triple == "aarch64-none-linux-gnueabi") {
    319     if (pointerSize != 64) {
    320       return kErrInvalidSource;
    321     }
    322   } else {
    323     return kErrInvalidSource;
    324   }
    325 
    326   if (script.isStructExplicitlyPaddedBySlang()) {
    327     if (!validateLayoutOfExportedTypes(module, module.getDataLayout(), dl))
    328       return kErrInvalidLayout;
    329   } else {
    330     if (getTargetMachine().getTargetTriple().getArch() == llvm::Triple::x86) {
    331       // Detect and fail if TargetMachine datalayout is different than what we
    332       // expect.  This is to detect changes in default target layout for x86 and
    333       // update X86_CUSTOM_DL_STRING in include/bcc/Config/Config.h appropriately.
    334       if (dl.getStringRepresentation().compare(X86_DEFAULT_DL_STRING) != 0) {
    335         return kErrInvalidTargetMachine;
    336       }
    337     }
    338   }
    339 
    340   // Sanitize module's target information.
    341   module.setTargetTriple(getTargetMachine().getTargetTriple().str());
    342   module.setDataLayout(getTargetMachine().createDataLayout());
    343 
    344   // Materialize the bitcode module.
    345   if (module.getMaterializer() != nullptr) {
    346     // A module with non-null materializer means that it is a lazy-load module.
    347     // Materialize it now.  This function returns false when the materialization
    348     // is successful.
    349     std::error_code ec = module.materializeAll();
    350     if (ec) {
    351       ALOGE("Failed to materialize the module `%s'! (%s)",
    352             module.getModuleIdentifier().c_str(), ec.message().c_str());
    353       return kErrMaterialization;
    354     }
    355   }
    356 
    357   if ((err = runPasses(script, pResult)) != kSuccess) {
    358     return err;
    359   }
    360 
    361   if (IRStream) {
    362     *IRStream << module;
    363   }
    364 
    365   return kSuccess;
    366 }
    367 
    368 bool Compiler::addInternalizeSymbolsPass(Script &script, llvm::legacy::PassManager &pPM) {
    369   // Add a pass to internalize the symbols that don't need to have global
    370   // visibility.
    371   llvm::Module &module = script.getSource().getModule();
    372   bcinfo::MetadataExtractor me(&module);
    373   if (!me.extract()) {
    374     bccAssert(false && "Could not extract metadata for module!");
    375     return false;
    376   }
    377 
    378   // Set of symbols that should not be internalized.
    379   std::set<std::string> export_symbols;
    380 
    381   const char *sf[] = {
    382     kRoot,               // Graphics drawing function or compute kernel.
    383     kInit,               // Initialization routine called implicitly on startup.
    384     kRsDtor,             // Static global destructor for a script instance.
    385     kRsInfo,             // Variable containing string of RS metadata info.
    386     kRsGlobalEntries,    // Optional number of global variables.
    387     kRsGlobalNames,      // Optional global variable name info.
    388     kRsGlobalAddresses,  // Optional global variable address info.
    389     kRsGlobalSizes,      // Optional global variable size info.
    390     kRsGlobalProperties, // Optional global variable properties.
    391     nullptr              // Must be nullptr-terminated.
    392   };
    393   const char **special_functions = sf;
    394   // Special RS functions should always be global symbols.
    395   while (*special_functions != nullptr) {
    396     export_symbols.insert(*special_functions);
    397     special_functions++;
    398   }
    399 
    400   // Visibility of symbols appeared in rs_export_var and rs_export_func should
    401   // also be preserved.
    402   size_t exportVarCount = me.getExportVarCount();
    403   size_t exportFuncCount = me.getExportFuncCount();
    404   size_t exportForEachCount = me.getExportForEachSignatureCount();
    405   size_t exportReduceCount = me.getExportReduceCount();
    406   const char **exportVarNameList = me.getExportVarNameList();
    407   const char **exportFuncNameList = me.getExportFuncNameList();
    408   const char **exportForEachNameList = me.getExportForEachNameList();
    409   const bcinfo::MetadataExtractor::Reduce *exportReduceList = me.getExportReduceList();
    410   size_t i;
    411 
    412   for (i = 0; i < exportVarCount; ++i) {
    413     export_symbols.insert(exportVarNameList[i]);
    414   }
    415 
    416   for (i = 0; i < exportFuncCount; ++i) {
    417     export_symbols.insert(exportFuncNameList[i]);
    418   }
    419 
    420   // Expanded foreach functions should not be internalized; nor should
    421   // general reduction initializer, combiner, and outconverter
    422   // functions. keep_funcs keeps the names of these functions around
    423   // until createInternalizePass() is finished making its own copy of
    424   // the visible symbols.
    425   std::vector<std::string> keep_funcs;
    426   keep_funcs.reserve(exportForEachCount + exportReduceCount*4);
    427 
    428   for (i = 0; i < exportForEachCount; ++i) {
    429     keep_funcs.push_back(std::string(exportForEachNameList[i]) + ".expand");
    430   }
    431   auto keepFuncsPushBackIfPresent = [&keep_funcs](const char *Name) {
    432     if (Name) keep_funcs.push_back(Name);
    433   };
    434   for (i = 0; i < exportReduceCount; ++i) {
    435     keep_funcs.push_back(std::string(exportReduceList[i].mAccumulatorName) + ".expand");
    436     keepFuncsPushBackIfPresent(exportReduceList[i].mInitializerName);
    437     if (exportReduceList[i].mCombinerName != nullptr) {
    438       keep_funcs.push_back(exportReduceList[i].mCombinerName);
    439     } else {
    440       keep_funcs.push_back(nameReduceCombinerFromAccumulator(exportReduceList[i].mAccumulatorName));
    441     }
    442     keepFuncsPushBackIfPresent(exportReduceList[i].mOutConverterName);
    443   }
    444 
    445   for (auto &symbol_name : keep_funcs) {
    446     export_symbols.insert(symbol_name);
    447   }
    448 
    449   auto IsExportedSymbol = [=](const llvm::GlobalValue &GV) {
    450     return export_symbols.count(GV.getName()) > 0;
    451   };
    452 
    453   pPM.add(llvm::createInternalizePass(IsExportedSymbol));
    454 
    455   return true;
    456 }
    457 
    458 void Compiler::addInvokeHelperPass(llvm::legacy::PassManager &pPM) {
    459   llvm::Triple arch(getTargetMachine().getTargetTriple());
    460   if (arch.isArch64Bit()) {
    461     pPM.add(createRSInvokeHelperPass());
    462   }
    463 }
    464 
    465 void Compiler::addDebugInfoPass(Script &script, llvm::legacy::PassManager &pPM) {
    466   if (script.getSource().getDebugInfoEnabled())
    467     pPM.add(createRSAddDebugInfoPass());
    468 }
    469 
    470 void Compiler::addExpandKernelPass(llvm::legacy::PassManager &pPM) {
    471   // Expand ForEach and reduce on CPU path to reduce launch overhead.
    472   bool pEnableStepOpt = true;
    473   pPM.add(createRSKernelExpandPass(pEnableStepOpt));
    474 }
    475 
    476 void Compiler::addGlobalInfoPass(Script &script, llvm::legacy::PassManager &pPM) {
    477   // Add additional information about RS global variables inside the Module.
    478   if (script.getEmbedGlobalInfo()) {
    479     pPM.add(createRSGlobalInfoPass(script.getEmbedGlobalInfoSkipConstant()));
    480   }
    481 }
    482 
    483 void Compiler::addInvariantPass(llvm::legacy::PassManager &pPM) {
    484   // Mark Loads from RsExpandKernelDriverInfo as "load.invariant".
    485   // Should run after ExpandForEach and before inlining.
    486   pPM.add(createRSInvariantPass());
    487 }
    488 
    489 enum Compiler::ErrorCode Compiler::screenGlobalFunctions(Script &script) {
    490   llvm::Module &module = script.getSource().getModule();
    491 
    492   // Materialize the bitcode module in case this is a lazy-load module.  Do not
    493   // clear the materializer by calling materializeAllPermanently since the
    494   // runtime library has not been merged into the module yet.
    495   if (module.getMaterializer() != nullptr) {
    496     std::error_code ec = module.materializeAll();
    497     if (ec) {
    498       ALOGE("Failed to materialize module `%s' when screening globals! (%s)",
    499             module.getModuleIdentifier().c_str(), ec.message().c_str());
    500       return kErrMaterialization;
    501     }
    502   }
    503 
    504   // Add pass to check for illegal function calls.
    505   llvm::legacy::PassManager pPM;
    506   pPM.add(createRSScreenFunctionsPass());
    507   pPM.run(module);
    508 
    509   return kSuccess;
    510 
    511 }
    512 
    513 void Compiler::translateGEPs(Script &script) {
    514   llvm::legacy::PassManager pPM;
    515   pPM.add(createRSX86TranslateGEPPass());
    516 
    517   // Materialization done in screenGlobalFunctions above.
    518   pPM.run(script.getSource().getModule());
    519 }
    520