MLIR  15.0.0git
DebugTranslation.cpp
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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"
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.
23  return op->getLoc().isa<UnknownLoc>() ? WalkResult::advance()
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: 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  if (auto targetTripleAttr =
53  module->getAttr(LLVM::LLVMDialect::getTargetTripleAttrName())) {
54  auto targetTriple =
55  llvm::Triple(targetTripleAttr.cast<StringAttr>().getValue());
56  if (targetTriple.isKnownWindowsMSVCEnvironment()) {
57  // Dwarf debugging files will be generated by default, unless "CodeView"
58  // is set explicitly. Windows/MSVC should use CodeView instead.
59  llvmModule.addModuleFlag(llvm::Module::Warning, "CodeView", 1);
60  }
61  }
62 }
63 
64 /// Finalize the translation of debug information.
65 void DebugTranslation::finalize() { builder.finalize(); }
66 
67 /// Attempt to extract a filename for the given loc.
68 static FileLineColLoc extractFileLoc(Location loc) {
69  if (auto fileLoc = loc.dyn_cast<FileLineColLoc>())
70  return fileLoc;
71  if (auto nameLoc = loc.dyn_cast<NameLoc>())
72  return extractFileLoc(nameLoc.getChildLoc());
73  if (auto opaqueLoc = loc.dyn_cast<OpaqueLoc>())
74  return extractFileLoc(opaqueLoc.getFallbackLocation());
75  return FileLineColLoc();
76 }
77 
78 /// Translate the debug information for the given function.
79 void DebugTranslation::translate(LLVMFuncOp func, llvm::Function &llvmFunc) {
80  // If the function doesn't have location information, there is nothing to
81  // translate.
82  if (!compileUnit || !func.walk(interruptIfValidLocation).wasInterrupted())
83  return;
84 
85  // If we are to create debug info for the function, we need to ensure that all
86  // inlinable calls in it are with debug info, otherwise the LLVM verifier will
87  // complain. For now, be more restricted and treat all calls as inlinable.
88  const bool hasCallWithoutDebugInfo =
89  func.walk([&](LLVM::CallOp call) {
90  return call.getLoc()->walk([](Location l) {
91  return l.isa<UnknownLoc>() ? WalkResult::interrupt()
93  });
94  })
95  .wasInterrupted();
96  if (hasCallWithoutDebugInfo)
97  return;
98 
99  FileLineColLoc fileLoc = extractFileLoc(func.getLoc());
100  auto *file =
101  translateFile(fileLoc ? fileLoc.getFilename().strref() : "<unknown>");
102  unsigned line = fileLoc ? fileLoc.getLine() : 0;
103 
104  // TODO: This is the bare essentials for now. We will likely end
105  // up with wrapper metadata around LLVMs metadata in the future, so this
106  // doesn't need to be smart until then.
107  llvm::DISubroutineType *type =
108  builder.createSubroutineType(builder.getOrCreateTypeArray(llvm::None));
109  llvm::DISubprogram::DISPFlags spFlags = llvm::DISubprogram::SPFlagDefinition |
110  llvm::DISubprogram::SPFlagOptimized;
111  llvm::DISubprogram *program =
112  builder.createFunction(compileUnit, func.getName(), func.getName(), file,
113  line, type, line, llvm::DINode::FlagZero, spFlags);
114  llvmFunc.setSubprogram(program);
115  builder.finalizeSubprogram(program);
116 }
117 
118 //===----------------------------------------------------------------------===//
119 // Locations
120 //===----------------------------------------------------------------------===//
121 
122 /// Translate the given location to an llvm debug location.
123 const llvm::DILocation *
124 DebugTranslation::translateLoc(Location loc, llvm::DILocalScope *scope) {
125  if (!compileUnit)
126  return nullptr;
127  return translateLoc(loc, scope, /*inlinedAt=*/nullptr);
128 }
129 
130 /// Translate the given location to an llvm DebugLoc.
131 const llvm::DILocation *
132 DebugTranslation::translateLoc(Location loc, llvm::DILocalScope *scope,
133  const llvm::DILocation *inlinedAt) {
134  // LLVM doesn't have a representation for unknown.
135  if (!scope || loc.isa<UnknownLoc>())
136  return nullptr;
137 
138  // Check for a cached instance.
139  auto existingIt = locationToLoc.find(std::make_pair(loc, scope));
140  if (existingIt != locationToLoc.end())
141  return existingIt->second;
142 
143  const llvm::DILocation *llvmLoc = nullptr;
144  if (auto callLoc = loc.dyn_cast<CallSiteLoc>()) {
145  // For callsites, the caller is fed as the inlinedAt for the callee.
146  const auto *callerLoc = translateLoc(callLoc.getCaller(), scope, inlinedAt);
147  llvmLoc = translateLoc(callLoc.getCallee(), scope, callerLoc);
148 
149  } else if (auto fileLoc = loc.dyn_cast<FileLineColLoc>()) {
150  auto *file = translateFile(fileLoc.getFilename());
151  auto *fileScope = builder.createLexicalBlockFile(scope, file);
152  llvmLoc = llvm::DILocation::get(llvmCtx, fileLoc.getLine(),
153  fileLoc.getColumn(), fileScope,
154  const_cast<llvm::DILocation *>(inlinedAt));
155 
156  } else if (auto fusedLoc = loc.dyn_cast<FusedLoc>()) {
157  ArrayRef<Location> locations = fusedLoc.getLocations();
158 
159  // For fused locations, merge each of the nodes.
160  llvmLoc = translateLoc(locations.front(), scope, inlinedAt);
161  for (Location locIt : locations.drop_front()) {
162  llvmLoc = llvm::DILocation::getMergedLocation(
163  llvmLoc, translateLoc(locIt, scope, inlinedAt));
164  }
165 
166  } else if (auto nameLoc = loc.dyn_cast<NameLoc>()) {
167  llvmLoc = translateLoc(loc.cast<NameLoc>().getChildLoc(), scope, inlinedAt);
168 
169  } else if (auto opaqueLoc = loc.dyn_cast<OpaqueLoc>()) {
170  llvmLoc = translateLoc(loc.cast<OpaqueLoc>().getFallbackLocation(), scope,
171  inlinedAt);
172  } else {
173  llvm_unreachable("unknown location kind");
174  }
175 
176  locationToLoc.try_emplace(std::make_pair(loc, scope), llvmLoc);
177  return llvmLoc;
178 }
179 
180 /// Create an llvm debug file for the given file path.
181 llvm::DIFile *DebugTranslation::translateFile(StringRef fileName) {
182  auto *&file = fileMap[fileName];
183  if (file)
184  return file;
185 
186  // Make sure the current working directory is up-to-date.
187  if (currentWorkingDir.empty())
188  llvm::sys::fs::current_path(currentWorkingDir);
189 
190  StringRef directory = currentWorkingDir;
191  SmallString<128> dirBuf;
192  SmallString<128> fileBuf;
193  if (llvm::sys::path::is_absolute(fileName)) {
194  // Strip the common prefix (if it is more than just "/") from current
195  // directory and FileName for a more space-efficient encoding.
196  auto fileIt = llvm::sys::path::begin(fileName);
197  auto fileE = llvm::sys::path::end(fileName);
198  auto curDirIt = llvm::sys::path::begin(directory);
199  auto curDirE = llvm::sys::path::end(directory);
200  for (; curDirIt != curDirE && *curDirIt == *fileIt; ++curDirIt, ++fileIt)
201  llvm::sys::path::append(dirBuf, *curDirIt);
202  if (std::distance(llvm::sys::path::begin(directory), curDirIt) == 1) {
203  // Don't strip the common prefix if it is only the root "/" since that
204  // would make LLVM diagnostic locations confusing.
205  directory = StringRef();
206  } else {
207  for (; fileIt != fileE; ++fileIt)
208  llvm::sys::path::append(fileBuf, *fileIt);
209  directory = dirBuf;
210  fileName = fileBuf;
211  }
212  }
213  return (file = builder.createFile(fileName, directory));
214 }
TODO: Remove this file when SCCP and integer range analysis have been ported to the new framework...
U cast() const
Definition: Location.h:67
const llvm::DILocation * translateLoc(Location loc, llvm::DILocalScope *scope)
Translate the given location to an llvm debug location.
Operation is a basic unit of execution within MLIR.
Definition: Operation.h:28
This class defines the main interface for locations in MLIR and acts as a non-nullable wrapper around...
Definition: Location.h:48
static WalkResult interruptIfValidLocation(Operation *op)
A utility walker that interrupts if the operation has valid debug information.
std::enable_if< llvm::function_traits< std::decay_t< FnT > >::num_args==1, RetT >::type walk(FnT &&callback)
Walk the operation by calling the callback for each nested operation (including this one)...
Definition: Operation.h:572
bool isa() const
Type casting utilities on the underlying location.
Definition: Location.h:65
void translate(LLVMFuncOp func, llvm::Function &llvmFunc)
Translate the debug information for the given function.
static FileLineColLoc extractFileLoc(Location loc)
Attempt to extract a filename for the given loc.
void finalize()
Finalize the translation of debug information.
static WalkResult advance()
Definition: Visitors.h:51
Location getLoc()
The source location the operation was defined or derived from.
Definition: Operation.h:161
static WalkResult interrupt()
Definition: Visitors.h:50
A utility result that is used to signal how to proceed with an ongoing walk:
Definition: Visitors.h:34
U dyn_cast() const
Definition: Location.h:66
Attribute getAttr(StringAttr name)
Return the specified attribute if present, null otherwise.
Definition: Operation.h:378
DebugTranslation(Operation *module, llvm::Module &llvmModule)