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| 1 | +//===- DebugTranslation.cpp - MLIR to LLVM Debug conversion ---------------===// |
| 2 | +// |
| 3 | +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | +// See https://llvm.org/LICENSE.txt for license information. |
| 5 | +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | +// |
| 7 | +//===----------------------------------------------------------------------===// |
| 8 | + |
| 9 | +#include "DebugTranslation.h" |
| 10 | +#include "mlir/Dialect/LLVMIR/LLVMDialect.h" |
| 11 | +#include "llvm/IR/Metadata.h" |
| 12 | +#include "llvm/IR/Module.h" |
| 13 | +#include "llvm/Support/FileSystem.h" |
| 14 | +#include "llvm/Support/Path.h" |
| 15 | + |
| 16 | +using namespace mlir; |
| 17 | +using namespace mlir::LLVM; |
| 18 | +using namespace mlir::LLVM::detail; |
| 19 | + |
| 20 | +/// A utility walker that interrupts if the operation has valid debug |
| 21 | +/// information. |
| 22 | +static WalkResult interruptIfValidLocation(Operation *op) { |
| 23 | + return op->getLoc().isa<UnknownLoc>() ? WalkResult::advance() |
| 24 | + : WalkResult::interrupt(); |
| 25 | +} |
| 26 | + |
| 27 | +DebugTranslation::DebugTranslation(Operation *module, llvm::Module &llvmModule) |
| 28 | + : builder(llvmModule), llvmCtx(llvmModule.getContext()), |
| 29 | + compileUnit(nullptr) { |
| 30 | + |
| 31 | + // If the module has no location information, there is nothing to do. |
| 32 | + if (!module->walk(interruptIfValidLocation).wasInterrupted()) |
| 33 | + return; |
| 34 | + |
| 35 | + // TODO(riverriddle) Several parts of this are incorrect. Different source |
| 36 | + // languages may interpret different parts of the debug information |
| 37 | + // differently. Frontends will also want to pipe in various information, like |
| 38 | + // flags. This is fine for now as we only emit line-table information and not |
| 39 | + // types or variables. This should disappear as the debug information story |
| 40 | + // evolves; i.e. when we have proper attributes for LLVM debug metadata. |
| 41 | + compileUnit = builder.createCompileUnit( |
| 42 | + llvm::dwarf::DW_LANG_C, |
| 43 | + builder.createFile(llvmModule.getModuleIdentifier(), "/"), |
| 44 | + /*Producer=*/"mlir", /*isOptimized=*/true, /*Flags=*/"", /*RV=*/0); |
| 45 | + |
| 46 | + // Mark this module as having debug information. |
| 47 | + StringRef debugVersionKey = "Debug Info Version"; |
| 48 | + if (!llvmModule.getModuleFlag(debugVersionKey)) |
| 49 | + llvmModule.addModuleFlag(llvm::Module::Warning, debugVersionKey, |
| 50 | + llvm::DEBUG_METADATA_VERSION); |
| 51 | +} |
| 52 | + |
| 53 | +/// Finalize the translation of debug information. |
| 54 | +void DebugTranslation::finalize() { builder.finalize(); } |
| 55 | + |
| 56 | +/// Attempt to extract a filename for the given loc. |
| 57 | +static FileLineColLoc extractFileLoc(Location loc) { |
| 58 | + if (auto fileLoc = loc.dyn_cast<FileLineColLoc>()) |
| 59 | + return fileLoc; |
| 60 | + if (auto nameLoc = loc.dyn_cast<NameLoc>()) |
| 61 | + return extractFileLoc(nameLoc.getChildLoc()); |
| 62 | + if (auto opaqueLoc = loc.dyn_cast<OpaqueLoc>()) |
| 63 | + return extractFileLoc(opaqueLoc.getFallbackLocation()); |
| 64 | + return FileLineColLoc(); |
| 65 | +} |
| 66 | + |
| 67 | +/// Translate the debug information for the given function. |
| 68 | +void DebugTranslation::translate(LLVMFuncOp func, llvm::Function &llvmFunc) { |
| 69 | + // If the function doesn't have location information, there is nothing to |
| 70 | + // translate. |
| 71 | + if (!compileUnit || !func.walk(interruptIfValidLocation).wasInterrupted()) |
| 72 | + return; |
| 73 | + |
| 74 | + FileLineColLoc fileLoc = extractFileLoc(func.getLoc()); |
| 75 | + auto *file = translateFile(fileLoc ? fileLoc.getFilename() : "<unknown>"); |
| 76 | + unsigned line = fileLoc ? fileLoc.getLine() : 0; |
| 77 | + |
| 78 | + // TODO(riverriddle) This is the bare essentials for now. We will likely end |
| 79 | + // up with wrapper metadata around LLVMs metadata in the future, so this |
| 80 | + // doesn't need to be smart until then. |
| 81 | + llvm::DISubroutineType *type = |
| 82 | + builder.createSubroutineType(builder.getOrCreateTypeArray(llvm::None)); |
| 83 | + llvm::DISubprogram::DISPFlags spFlags = llvm::DISubprogram::SPFlagDefinition | |
| 84 | + llvm::DISubprogram::SPFlagOptimized; |
| 85 | + llvm::DISubprogram *program = |
| 86 | + builder.createFunction(compileUnit, func.getName(), func.getName(), file, |
| 87 | + line, type, line, llvm::DINode::FlagZero, spFlags); |
| 88 | + llvmFunc.setSubprogram(program); |
| 89 | + builder.finalizeSubprogram(program); |
| 90 | +} |
| 91 | + |
| 92 | +//===----------------------------------------------------------------------===// |
| 93 | +// Locations |
| 94 | +//===----------------------------------------------------------------------===// |
| 95 | + |
| 96 | +/// Translate the given location to an llvm debug location. |
| 97 | +const llvm::DILocation * |
| 98 | +DebugTranslation::translateLoc(Location loc, llvm::DILocalScope *scope) { |
| 99 | + if (!compileUnit) |
| 100 | + return nullptr; |
| 101 | + return translateLoc(loc, scope, /*inlinedAt=*/nullptr); |
| 102 | +} |
| 103 | + |
| 104 | +/// Translate the given location to an llvm DebugLoc. |
| 105 | +const llvm::DILocation * |
| 106 | +DebugTranslation::translateLoc(Location loc, llvm::DILocalScope *scope, |
| 107 | + const llvm::DILocation *inlinedAt) { |
| 108 | + // LLVM doesn't have a representation for unknown. |
| 109 | + if (!scope || loc.isa<UnknownLoc>()) |
| 110 | + return nullptr; |
| 111 | + |
| 112 | + // Check for a cached instance. |
| 113 | + const auto *&llvmLoc = locationToLoc[std::make_pair(loc, scope)]; |
| 114 | + if (llvmLoc) |
| 115 | + return llvmLoc; |
| 116 | + |
| 117 | + switch (loc->getKind()) { |
| 118 | + case StandardAttributes::CallSiteLocation: { |
| 119 | + auto callLoc = loc.dyn_cast<CallSiteLoc>(); |
| 120 | + |
| 121 | + // For callsites, the caller is fed as the inlinedAt for the callee. |
| 122 | + const auto *callerLoc = translateLoc(callLoc.getCaller(), scope, inlinedAt); |
| 123 | + llvmLoc = translateLoc(callLoc.getCallee(), scope, callerLoc); |
| 124 | + break; |
| 125 | + } |
| 126 | + case StandardAttributes::FileLineColLocation: { |
| 127 | + auto fileLoc = loc.dyn_cast<FileLineColLoc>(); |
| 128 | + auto *file = translateFile(fileLoc.getFilename()); |
| 129 | + auto *fileScope = builder.createLexicalBlockFile(scope, file); |
| 130 | + llvmLoc = llvm::DILocation::get(llvmCtx, fileLoc.getLine(), |
| 131 | + fileLoc.getColumn(), fileScope, |
| 132 | + const_cast<llvm::DILocation *>(inlinedAt)); |
| 133 | + break; |
| 134 | + } |
| 135 | + case StandardAttributes::FusedLocation: { |
| 136 | + auto fusedLoc = loc.dyn_cast<FusedLoc>(); |
| 137 | + ArrayRef<Location> locations = fusedLoc.getLocations(); |
| 138 | + |
| 139 | + // For fused locations, merge each of the nodes. |
| 140 | + llvmLoc = translateLoc(locations.front(), scope, inlinedAt); |
| 141 | + for (Location locIt : locations.drop_front()) { |
| 142 | + llvmLoc = llvm::DILocation::getMergedLocation( |
| 143 | + llvmLoc, translateLoc(locIt, scope, inlinedAt)); |
| 144 | + } |
| 145 | + break; |
| 146 | + } |
| 147 | + case StandardAttributes::NameLocation: |
| 148 | + llvmLoc = translateLoc(loc.cast<NameLoc>().getChildLoc(), scope, inlinedAt); |
| 149 | + break; |
| 150 | + case StandardAttributes::OpaqueLocation: |
| 151 | + llvmLoc = translateLoc(loc.cast<OpaqueLoc>().getFallbackLocation(), scope, |
| 152 | + inlinedAt); |
| 153 | + break; |
| 154 | + default: |
| 155 | + llvm_unreachable("unknown location kind"); |
| 156 | + } |
| 157 | + return llvmLoc; |
| 158 | +} |
| 159 | + |
| 160 | +/// Create an llvm debug file for the given file path. |
| 161 | +llvm::DIFile *DebugTranslation::translateFile(StringRef fileName) { |
| 162 | + auto *&file = fileMap[fileName]; |
| 163 | + if (file) |
| 164 | + return file; |
| 165 | + |
| 166 | + // Make sure the current working directory is up-to-date. |
| 167 | + if (currentWorkingDir.empty()) |
| 168 | + llvm::sys::fs::current_path(currentWorkingDir); |
| 169 | + |
| 170 | + StringRef directory = currentWorkingDir; |
| 171 | + SmallString<128> dirBuf; |
| 172 | + SmallString<128> fileBuf; |
| 173 | + if (llvm::sys::path::is_absolute(fileName)) { |
| 174 | + // Strip the common prefix (if it is more than just "/") from current |
| 175 | + // directory and FileName for a more space-efficient encoding. |
| 176 | + auto fileIt = llvm::sys::path::begin(fileName); |
| 177 | + auto fileE = llvm::sys::path::end(fileName); |
| 178 | + auto curDirIt = llvm::sys::path::begin(directory); |
| 179 | + auto curDirE = llvm::sys::path::end(directory); |
| 180 | + for (; curDirIt != curDirE && *curDirIt == *fileIt; ++curDirIt, ++fileIt) |
| 181 | + llvm::sys::path::append(dirBuf, *curDirIt); |
| 182 | + if (std::distance(llvm::sys::path::begin(directory), curDirIt) == 1) { |
| 183 | + // Don't strip the common prefix if it is only the root "/" since that |
| 184 | + // would make LLVM diagnostic locations confusing. |
| 185 | + directory = StringRef(); |
| 186 | + } else { |
| 187 | + for (; fileIt != fileE; ++fileIt) |
| 188 | + llvm::sys::path::append(fileBuf, *fileIt); |
| 189 | + directory = dirBuf; |
| 190 | + fileName = fileBuf; |
| 191 | + } |
| 192 | + } |
| 193 | + return (file = builder.createFile(fileName, directory)); |
| 194 | +} |
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