[llvm] r268334 - NFC: An iterator for stepping through CodeView type stream in llvm-readobj
Adrian McCarthy via llvm-commits
llvm-commits at lists.llvm.org
Mon May 2 16:45:03 PDT 2016
Author: amccarth
Date: Mon May 2 18:45:03 2016
New Revision: 268334
URL: http://llvm.org/viewvc/llvm-project?rev=268334&view=rev
Log:
NFC: An iterator for stepping through CodeView type stream in llvm-readobj
This is a small refactoring step toward moving CodeView type stream logic from llvm-readobj to a library. It abstracts the logic of stepping through the stream into an iterator class and updates llvm-readobj to use that iterator. This has no functional change; llvm-readobj produces identical output.
The next step is to abstract the parsing of the different leaf types and then move that and the iterator into a library.
Since this is my first contrib outside LLDB, please let me know if I'm messing up on any of the LLVM style guidelines, idioms, or patterns.
Differential Revision: http://reviews.llvm.org/D19746
Modified:
llvm/trunk/tools/llvm-readobj/COFFDumper.cpp
Modified: llvm/trunk/tools/llvm-readobj/COFFDumper.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-readobj/COFFDumper.cpp?rev=268334&r1=268333&r2=268334&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-readobj/COFFDumper.cpp (original)
+++ llvm/trunk/tools/llvm-readobj/COFFDumper.cpp Mon May 2 18:45:03 2016
@@ -1866,19 +1866,9 @@ void COFFDumper::printCodeViewInlineeLin
}
}
-StringRef getRemainingTypeBytes(const TypeRecordPrefix *Rec, const char *Start) {
- ptrdiff_t StartOffset = Start - reinterpret_cast<const char *>(Rec);
- size_t RecSize = Rec->Len + 2;
- assert(StartOffset >= 0 && "negative start-offset!");
- assert(static_cast<size_t>(StartOffset) <= RecSize &&
- "Start beyond the end of Rec");
- return StringRef(Start, RecSize - StartOffset);
-}
-
-StringRef getRemainingBytesAsString(const TypeRecordPrefix *Rec, const char *Start) {
- StringRef Remaining = getRemainingTypeBytes(Rec, Start);
- StringRef Leading, Trailing;
- std::tie(Leading, Trailing) = Remaining.split('\0');
+StringRef getLeafDataBytesAsString(StringRef LeafData) {
+ StringRef Leading;
+ std::tie(Leading, std::ignore) = LeafData.split('\0');
return Leading;
}
@@ -1992,47 +1982,148 @@ static StringRef getLeafTypeName(TypeLea
return "UnknownLeaf";
}
+// A const input iterator interface to the CodeView type stream.
+class CodeViewTypeIterator {
+public:
+ struct TypeRecord {
+ std::size_t Length;
+ TypeLeafKind Leaf;
+ StringRef LeafData;
+ };
+
+ explicit CodeViewTypeIterator(const StringRef &SectionData)
+ : Data(SectionData), AtEnd(false) {
+ if (Data.size() >= 4) {
+ Magic = *reinterpret_cast<const ulittle32_t *>(Data.data());
+ Data = Data.drop_front(4);
+ }
+ next(); // Prime the pump
+ }
+
+ CodeViewTypeIterator() : AtEnd(true) {}
+
+ // For iterators to compare equal, they must both point at the same record
+ // in the same data stream, or they must both be at the end of a stream.
+ friend bool operator==(const CodeViewTypeIterator &lhs,
+ const CodeViewTypeIterator &rhs);
+
+ friend bool operator!=(const CodeViewTypeIterator &lhs,
+ const CodeViewTypeIterator &rhs);
+
+ unsigned getMagic() const { return Magic; }
+
+ const TypeRecord &operator*() const {
+ assert(!AtEnd);
+ return Current;
+ }
+
+ const TypeRecord *operator->() const {
+ assert(!AtEnd);
+ return &Current;
+ }
+
+ CodeViewTypeIterator operator++() {
+ next();
+ return *this;
+ }
+
+ CodeViewTypeIterator operator++(int) {
+ CodeViewTypeIterator Original = *this;
+ ++*this;
+ return Original;
+ }
+
+private:
+ void next() {
+ assert(!AtEnd && "Attempted to advance more than one past the last rec");
+ if (Data.empty()) {
+ // We've advanced past the last record.
+ AtEnd = true;
+ return;
+ }
+
+ const TypeRecordPrefix *Rec;
+ if (consumeObject(Data, Rec))
+ return;
+ Current.Length = Rec->Len;
+ Current.Leaf = static_cast<TypeLeafKind>(uint16_t(Rec->Leaf));
+ Current.LeafData = Data.substr(0, Current.Length - 2);
+
+ // The next record starts immediately after this one.
+ Data = Data.drop_front(Current.LeafData.size());
+
+ // FIXME: The stream contains LF_PAD bytes that we need to ignore, but those
+ // are typically included in LeafData. We may need to call skipPadding() if
+ // we ever find a record that doesn't count those bytes.
+
+ return;
+ }
+
+ StringRef Data;
+ unsigned Magic = 0;
+ TypeRecord Current;
+ bool AtEnd;
+};
+
+bool operator==(const CodeViewTypeIterator &lhs,
+ const CodeViewTypeIterator &rhs) {
+ return (lhs.Data.begin() == rhs.Data.begin()) || (lhs.AtEnd && rhs.AtEnd);
+}
+
+bool operator!=(const CodeViewTypeIterator &lhs,
+ const CodeViewTypeIterator &rhs) {
+ return !(lhs == rhs);
+}
+
+struct CodeViewTypeStream {
+ CodeViewTypeIterator begin;
+ CodeViewTypeIterator end;
+ unsigned Magic;
+};
+
+CodeViewTypeStream CreateCodeViewTypeIter(const StringRef &Data) {
+ CodeViewTypeStream Stream;
+ Stream.begin = CodeViewTypeIterator(Data);
+ Stream.end = CodeViewTypeIterator();
+ Stream.Magic = Stream.begin.getMagic();
+
+ return Stream;
+}
+
void COFFDumper::printCodeViewTypeSection(StringRef SectionName,
const SectionRef &Section) {
ListScope D(W, "CodeViewTypes");
W.printNumber("Section", SectionName, Obj->getSectionID(Section));
+
StringRef Data;
error(Section.getContents(Data));
if (opts::CodeViewSubsectionBytes)
W.printBinaryBlock("Data", Data);
- unsigned Magic = *reinterpret_cast<const ulittle32_t *>(Data.data());
- W.printHex("Magic", Magic);
-
- Data = Data.drop_front(4);
-
CVTD.dump(Data);
}
void CVTypeDumper::dump(StringRef Data) {
- while (!Data.empty()) {
- const TypeRecordPrefix *Rec;
- error(consumeObject(Data, Rec));
- auto Leaf = static_cast<TypeLeafKind>(uint16_t(Rec->Leaf));
+ CodeViewTypeStream Stream = CreateCodeViewTypeIter(Data);
+ W.printHex("Magic", Stream.Magic);
- // This record is 'Len - 2' bytes, and the next one starts immediately
- // afterwards.
- StringRef LeafData = Data.substr(0, Rec->Len - 2);
- StringRef RemainingData = Data.drop_front(LeafData.size());
+ for (auto Iter = Stream.begin; Iter != Stream.end; ++Iter) {
+ StringRef LeafData = Iter->LeafData;
// Find the name of this leaf type.
- StringRef LeafName = getLeafTypeName(Leaf);
+ StringRef LeafName = getLeafTypeName(Iter->Leaf);
DictScope S(W, LeafName);
unsigned NextTypeIndex = 0x1000 + CVUDTNames.size();
- W.printEnum("TypeLeafKind", unsigned(Leaf), makeArrayRef(LeafTypeNames));
+ W.printEnum("TypeLeafKind", unsigned(Iter->Leaf),
+ makeArrayRef(LeafTypeNames));
W.printHex("TypeIndex", NextTypeIndex);
// Fill this in inside the switch to get something in CVUDTNames.
StringRef Name;
- switch (Leaf) {
+ switch (Iter->Leaf) {
default: {
- W.printHex("Size", Rec->Len);
+ W.printHex("Size", Iter->Length);
break;
}
@@ -2040,7 +2131,7 @@ void CVTypeDumper::dump(StringRef Data)
const StringId *String;
error(consumeObject(LeafData, String));
W.printHex("Id", String->id.getIndex());
- StringRef StringData = getRemainingBytesAsString(Rec, LeafData.data());
+ StringRef StringData = getLeafDataBytesAsString(LeafData);
W.printString("StringData", StringData);
// Put this in CVUDTNames so it gets printed with LF_UDT_SRC_LINE.
Name = StringData;
@@ -2048,7 +2139,7 @@ void CVTypeDumper::dump(StringRef Data)
}
case LF_FIELDLIST: {
- W.printHex("Size", Rec->Len);
+ W.printHex("Size", Iter->Length);
// FieldList has no fixed prefix that can be described with a struct. All
// the bytes must be interpreted as more records.
printCodeViewFieldList(LeafData);
@@ -2094,7 +2185,7 @@ void CVTypeDumper::dump(StringRef Data)
std::tie(Name, LinkageName) = LeafData.split('\0');
W.printString("Name", Name);
if (Props & uint16_t(ClassOptions::HasUniqueName)) {
- LinkageName = getRemainingBytesAsString(Rec, LinkageName.data());
+ LinkageName = getLeafDataBytesAsString(LinkageName);
if (LinkageName.empty())
return error(object_error::parse_failed);
W.printString("LinkageName", LinkageName);
@@ -2116,7 +2207,7 @@ void CVTypeDumper::dump(StringRef Data)
std::tie(Name, LinkageName) = LeafData.split('\0');
W.printString("Name", Name);
if (Props & uint16_t(ClassOptions::HasUniqueName)) {
- LinkageName = getRemainingBytesAsString(Rec, LinkageName.data());
+ LinkageName = getLeafDataBytesAsString(LinkageName);
if (LinkageName.empty())
return error(object_error::parse_failed);
W.printString("LinkageName", LinkageName);
@@ -2371,11 +2462,6 @@ void CVTypeDumper::dump(StringRef Data)
W.printBinaryBlock("LeafData", LeafData);
CVUDTNames.push_back(Name);
-
- Data = RemainingData;
- // FIXME: The stream contains LF_PAD bytes that we need to ignore, but those
- // are typically included in LeafData. We may need to call skipPadding() if
- // we ever find a record that doesn't count those bytes.
}
}
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