1 files changed, 276 insertions, 0 deletions
diff --git a/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
new file mode 100644
index 00000000000..4695de8ea09
--- /dev/null
+++ b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
@@ -0,0 +1,276 @@
+#include "LLVMWrapper.h"
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/IR/Module.h"
+#include "llvm/ProfileData/Coverage/CoverageMapping.h"
+#include "llvm/ProfileData/Coverage/CoverageMappingWriter.h"
+#include "llvm/ProfileData/InstrProf.h"
+
+using namespace llvm;
+
+// FFI equivalent of enum `llvm::coverage::Counter::CounterKind`
+// https://github.com/rust-lang/llvm-project/blob/ea6fa9c2/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L97-L99
+enum class LLVMRustCounterKind {
+  Zero = 0,
+  CounterValueReference = 1,
+  Expression = 2,
+};
+
+// FFI equivalent of struct `llvm::coverage::Counter`
+// https://github.com/rust-lang/llvm-project/blob/ea6fa9c2/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L94-L149
+struct LLVMRustCounter {
+  LLVMRustCounterKind CounterKind;
+  uint32_t ID;
+};
+
+static coverage::Counter fromRust(LLVMRustCounter Counter) {
+  switch (Counter.CounterKind) {
+  case LLVMRustCounterKind::Zero:
+    return coverage::Counter::getZero();
+  case LLVMRustCounterKind::CounterValueReference:
+    return coverage::Counter::getCounter(Counter.ID);
+  case LLVMRustCounterKind::Expression:
+    return coverage::Counter::getExpression(Counter.ID);
+  }
+  report_fatal_error("Bad LLVMRustCounterKind!");
+}
+
+struct LLVMRustMCDCDecisionParameters {
+  uint32_t BitmapIdx;
+  uint16_t NumConditions;
+};
+
+struct LLVMRustMCDCBranchParameters {
+  int16_t ConditionID;
+  int16_t ConditionIDs[2];
+};
+
+static coverage::mcdc::BranchParameters
+fromRust(LLVMRustMCDCBranchParameters Params) {
+  return coverage::mcdc::BranchParameters(
+      Params.ConditionID, {Params.ConditionIDs[0], Params.ConditionIDs[1]});
+}
+
+static coverage::mcdc::DecisionParameters
+fromRust(LLVMRustMCDCDecisionParameters Params) {
+  return coverage::mcdc::DecisionParameters(Params.BitmapIdx,
+                                            Params.NumConditions);
+}
+
+// Must match the layout of
+// `rustc_codegen_llvm::coverageinfo::ffi::CoverageSpan`.
+struct LLVMRustCoverageSpan {
+  uint32_t FileID;
+  uint32_t LineStart;
+  uint32_t ColumnStart;
+  uint32_t LineEnd;
+  uint32_t ColumnEnd;
+};
+
+// Must match the layout of `rustc_codegen_llvm::coverageinfo::ffi::CodeRegion`.
+struct LLVMRustCoverageCodeRegion {
+  LLVMRustCoverageSpan Span;
+  LLVMRustCounter Count;
+};
+
+// Must match the layout of
+// `rustc_codegen_llvm::coverageinfo::ffi::ExpansionRegion`.
+struct LLVMRustCoverageExpansionRegion {
+  LLVMRustCoverageSpan Span;
+  uint32_t ExpandedFileID;
+};
+
+// Must match the layout of
+// `rustc_codegen_llvm::coverageinfo::ffi::BranchRegion`.
+struct LLVMRustCoverageBranchRegion {
+  LLVMRustCoverageSpan Span;
+  LLVMRustCounter TrueCount;
+  LLVMRustCounter FalseCount;
+};
+
+// Must match the layout of
+// `rustc_codegen_llvm::coverageinfo::ffi::MCDCBranchRegion`.
+struct LLVMRustCoverageMCDCBranchRegion {
+  LLVMRustCoverageSpan Span;
+  LLVMRustCounter TrueCount;
+  LLVMRustCounter FalseCount;
+  LLVMRustMCDCBranchParameters MCDCBranchParams;
+};
+
+// Must match the layout of
+// `rustc_codegen_llvm::coverageinfo::ffi::MCDCDecisionRegion`.
+struct LLVMRustCoverageMCDCDecisionRegion {
+  LLVMRustCoverageSpan Span;
+  LLVMRustMCDCDecisionParameters MCDCDecisionParams;
+};
+
+// FFI equivalent of enum `llvm::coverage::CounterExpression::ExprKind`
+// https://github.com/rust-lang/llvm-project/blob/ea6fa9c2/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L154
+enum class LLVMRustCounterExprKind {
+  Subtract = 0,
+  Add = 1,
+};
+
+// FFI equivalent of struct `llvm::coverage::CounterExpression`
+// https://github.com/rust-lang/llvm-project/blob/ea6fa9c2/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L151-L160
+struct LLVMRustCounterExpression {
+  LLVMRustCounterExprKind Kind;
+  LLVMRustCounter LHS;
+  LLVMRustCounter RHS;
+};
+
+static coverage::CounterExpression::ExprKind
+fromRust(LLVMRustCounterExprKind Kind) {
+  switch (Kind) {
+  case LLVMRustCounterExprKind::Subtract:
+    return coverage::CounterExpression::Subtract;
+  case LLVMRustCounterExprKind::Add:
+    return coverage::CounterExpression::Add;
+  }
+  report_fatal_error("Bad LLVMRustCounterExprKind!");
+}
+
+extern "C" void LLVMRustCoverageWriteFilenamesToBuffer(
+    const char *const Filenames[], size_t FilenamesLen, // String start pointers
+    const size_t *const Lengths, size_t LengthsLen,     // Corresponding lengths
+    RustStringRef BufferOut) {
+  if (FilenamesLen != LengthsLen) {
+    report_fatal_error(
+        "Mismatched lengths in LLVMRustCoverageWriteFilenamesToBuffer");
+  }
+
+  SmallVector<std::string, 32> FilenameRefs;
+  FilenameRefs.reserve(FilenamesLen);
+  for (size_t i = 0; i < FilenamesLen; i++) {
+    FilenameRefs.emplace_back(Filenames[i], Lengths[i]);
+  }
+  auto FilenamesWriter = coverage::CoverageFilenamesSectionWriter(
+      ArrayRef<std::string>(FilenameRefs));
+  auto OS = RawRustStringOstream(BufferOut);
+  FilenamesWriter.write(OS);
+}
+
+extern "C" void LLVMRustCoverageWriteFunctionMappingsToBuffer(
+    const unsigned *VirtualFileMappingIDs, size_t NumVirtualFileMappingIDs,
+    const LLVMRustCounterExpression *RustExpressions, size_t NumExpressions,
+    const LLVMRustCoverageCodeRegion *CodeRegions, size_t NumCodeRegions,
+    const LLVMRustCoverageExpansionRegion *ExpansionRegions,
+    size_t NumExpansionRegions,
+    const LLVMRustCoverageBranchRegion *BranchRegions, size_t NumBranchRegions,
+    const LLVMRustCoverageMCDCBranchRegion *MCDCBranchRegions,
+    size_t NumMCDCBranchRegions,
+    const LLVMRustCoverageMCDCDecisionRegion *MCDCDecisionRegions,
+    size_t NumMCDCDecisionRegions, RustStringRef BufferOut) {
+  // Convert from FFI representation to LLVM representation.
+
+  // Expressions:
+  std::vector<coverage::CounterExpression> Expressions;
+  Expressions.reserve(NumExpressions);
+  for (const auto &Expression :
+       ArrayRef<LLVMRustCounterExpression>(RustExpressions, NumExpressions)) {
+    Expressions.emplace_back(fromRust(Expression.Kind),
+                             fromRust(Expression.LHS),
+                             fromRust(Expression.RHS));
+  }
+
+  std::vector<coverage::CounterMappingRegion> MappingRegions;
+  MappingRegions.reserve(NumCodeRegions + NumBranchRegions +
+                         NumMCDCBranchRegions + NumMCDCDecisionRegions);
+
+  // Code regions:
+  for (const auto &Region : ArrayRef(CodeRegions, NumCodeRegions)) {
+    MappingRegions.push_back(coverage::CounterMappingRegion::makeRegion(
+        fromRust(Region.Count), Region.Span.FileID, Region.Span.LineStart,
+        Region.Span.ColumnStart, Region.Span.LineEnd, Region.Span.ColumnEnd));
+  }
+
+  // Expansion regions:
+  for (const auto &Region : ArrayRef(ExpansionRegions, NumExpansionRegions)) {
+    MappingRegions.push_back(coverage::CounterMappingRegion::makeExpansion(
+        Region.Span.FileID, Region.ExpandedFileID, Region.Span.LineStart,
+        Region.Span.ColumnStart, Region.Span.LineEnd, Region.Span.ColumnEnd));
+  }
+
+  // Branch regions:
+  for (const auto &Region : ArrayRef(BranchRegions, NumBranchRegions)) {
+    MappingRegions.push_back(coverage::CounterMappingRegion::makeBranchRegion(
+        fromRust(Region.TrueCount), fromRust(Region.FalseCount),
+        Region.Span.FileID, Region.Span.LineStart, Region.Span.ColumnStart,
+        Region.Span.LineEnd, Region.Span.ColumnEnd));
+  }
+
+  // MC/DC branch regions:
+  for (const auto &Region : ArrayRef(MCDCBranchRegions, NumMCDCBranchRegions)) {
+    MappingRegions.push_back(coverage::CounterMappingRegion::makeBranchRegion(
+        fromRust(Region.TrueCount), fromRust(Region.FalseCount),
+        Region.Span.FileID, Region.Span.LineStart, Region.Span.ColumnStart,
+        Region.Span.LineEnd, Region.Span.ColumnEnd,
+        fromRust(Region.MCDCBranchParams)));
+  }
+
+  // MC/DC decision regions:
+  for (const auto &Region :
+       ArrayRef(MCDCDecisionRegions, NumMCDCDecisionRegions)) {
+    MappingRegions.push_back(coverage::CounterMappingRegion::makeDecisionRegion(
+        fromRust(Region.MCDCDecisionParams), Region.Span.FileID,
+        Region.Span.LineStart, Region.Span.ColumnStart, Region.Span.LineEnd,
+        Region.Span.ColumnEnd));
+  }
+
+  // Write the converted expressions and mappings to a byte buffer.
+  auto CoverageMappingWriter = coverage::CoverageMappingWriter(
+      ArrayRef<unsigned>(VirtualFileMappingIDs, NumVirtualFileMappingIDs),
+      Expressions, MappingRegions);
+  auto OS = RawRustStringOstream(BufferOut);
+  CoverageMappingWriter.write(OS);
+}
+
+extern "C" LLVMValueRef
+LLVMRustCoverageCreatePGOFuncNameVar(LLVMValueRef F, const char *FuncName,
+                                     size_t FuncNameLen) {
+  auto FuncNameRef = StringRef(FuncName, FuncNameLen);
+  return wrap(createPGOFuncNameVar(*cast<Function>(unwrap(F)), FuncNameRef));
+}
+
+extern "C" uint64_t LLVMRustCoverageHashBytes(const char *Bytes,
+                                              size_t NumBytes) {
+  return IndexedInstrProf::ComputeHash(StringRef(Bytes, NumBytes));
+}
+
+// Private helper function for getting the covmap and covfun section names.
+static void writeInstrProfSectionNameToString(LLVMModuleRef M,
+                                              InstrProfSectKind SectKind,
+                                              RustStringRef OutStr) {
+  auto TargetTriple = Triple(unwrap(M)->getTargetTriple());
+  auto name = getInstrProfSectionName(SectKind, TargetTriple.getObjectFormat());
+  auto OS = RawRustStringOstream(OutStr);
+  OS << name;
+}
+
+extern "C" void
+LLVMRustCoverageWriteCovmapSectionNameToString(LLVMModuleRef M,
+                                               RustStringRef OutStr) {
+  writeInstrProfSectionNameToString(M, IPSK_covmap, OutStr);
+}
+
+extern "C" void
+LLVMRustCoverageWriteCovfunSectionNameToString(LLVMModuleRef M,
+                                               RustStringRef OutStr) {
+  writeInstrProfSectionNameToString(M, IPSK_covfun, OutStr);
+}
+
+extern "C" void
+LLVMRustCoverageWriteCovmapVarNameToString(RustStringRef OutStr) {
+  auto name = getCoverageMappingVarName();
+  auto OS = RawRustStringOstream(OutStr);
+  OS << name;
+}
+
+extern "C" uint32_t LLVMRustCoverageMappingVersion() {
+  // This should always be `CurrentVersion`, because that's the version LLVM
+  // will use when encoding the data we give it. If for some reason we ever
+  // want to override the version number we _emit_, do it on the Rust side.
+  return coverage::CovMapVersion::CurrentVersion;
+}