From 4d28d3f32e7f213e300b24bc61c3f0ac9d6e1ab6 Mon Sep 17 00:00:00 2001 From: Alon Zakai Date: Thu, 19 Dec 2019 09:04:08 -0800 Subject: DWARF parsing and writing support using LLVM (#2520) This imports LLVM code for DWARF handling. That code has the Apache 2 license like us. It's also the same code used to emit DWARF in the common toolchain, so it seems like a safe choice. This adds two passes: --dwarfdump which runs the same code LLVM runs for llvm-dwarfdump. This shows we can parse it ok, and will be useful for debugging. And --dwarfupdate writes out the DWARF sections (unchanged from what we read, so it just roundtrips - for updating we need #2515). This puts LLVM in thirdparty which is added here. All the LLVM code is behind USE_LLVM_DWARF, which is on by default, but off in JS for now, as it increases code size by 20%. This current approach imports the LLVM files directly. This is not how they are intended to be used, so it required a bunch of local changes - more than I expected actually, for the platform-specific stuff. For now this seems to work, so it may be good enough, but in the long term we may want to switch to linking against libllvm. A downside to doing that is that binaryen users would need to have an LLVM build, and even in the waterfall builds we'd have a problem - while we ship LLVM there anyhow, we constantly update it, which means that binaryen would need to be on latest llvm all the time too (which otherwise, given DWARF is quite stable, we might not need to constantly update). An even larger issue is that as I did this work I learned about how DWARF works in LLVM, and while the reading code is easy to reuse, the writing code is trickier. The main code path is heavily integrated with the MC layer, which we don't have - we might want to create a "fake MC layer" for that, but it sounds hard. Instead, there is the YAML path which is used mostly for testing, and which can convert DWARF to and from YAML and from binary. Using the non-YAML parts there, we can convert binary DWARF to the YAML layer's nice Info data, then convert that to binary. This works, however, this is not the path LLVM uses normally, and it supports only some basic DWARF sections - I had to add ranges support, in fact. So if we need more complex things, we may end up needing to use the MC layer approach, or consider some other DWARF library. However, hopefully that should not affect the core binaryen code which just calls a library for DWARF stuff. Helps #2400 --- third_party/llvm-project/StringRef.cpp | 519 +++++++++++++++++++++++++++++++++ 1 file changed, 519 insertions(+) create mode 100644 third_party/llvm-project/StringRef.cpp (limited to 'third_party/llvm-project/StringRef.cpp') diff --git a/third_party/llvm-project/StringRef.cpp b/third_party/llvm-project/StringRef.cpp new file mode 100644 index 000000000..08af7eaac --- /dev/null +++ b/third_party/llvm-project/StringRef.cpp @@ -0,0 +1,519 @@ +//===-- StringRef.cpp - Lightweight String References ---------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "llvm/ADT/StringRef.h" +#include "llvm/ADT/APFloat.h" +#include "llvm/ADT/APInt.h" +#include "llvm/ADT/Hashing.h" +#include "llvm/ADT/StringExtras.h" +#include "llvm/ADT/edit_distance.h" +#include + +using namespace llvm; + +// MSVC emits references to this into the translation units which reference it. +#ifndef _MSC_VER +const size_t StringRef::npos; +#endif + +// strncasecmp() is not available on non-POSIX systems, so define an +// alternative function here. +static int ascii_strncasecmp(const char *LHS, const char *RHS, size_t Length) { + for (size_t I = 0; I < Length; ++I) { + unsigned char LHC = toLower(LHS[I]); + unsigned char RHC = toLower(RHS[I]); + if (LHC != RHC) + return LHC < RHC ? -1 : 1; + } + return 0; +} + +/// compare_lower - Compare strings, ignoring case. +int StringRef::compare_lower(StringRef RHS) const { + if (int Res = ascii_strncasecmp(Data, RHS.Data, std::min(Length, RHS.Length))) + return Res; + if (Length == RHS.Length) + return 0; + return Length < RHS.Length ? -1 : 1; +} + +/// Check if this string starts with the given \p Prefix, ignoring case. +bool StringRef::startswith_lower(StringRef Prefix) const { + return Length >= Prefix.Length && + ascii_strncasecmp(Data, Prefix.Data, Prefix.Length) == 0; +} + +/// Check if this string ends with the given \p Suffix, ignoring case. +bool StringRef::endswith_lower(StringRef Suffix) const { + return Length >= Suffix.Length && + ascii_strncasecmp(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0; +} + +size_t StringRef::find_lower(char C, size_t From) const { + char L = toLower(C); + return find_if([L](char D) { return toLower(D) == L; }, From); +} + +/// compare_numeric - Compare strings, handle embedded numbers. +int StringRef::compare_numeric(StringRef RHS) const { + for (size_t I = 0, E = std::min(Length, RHS.Length); I != E; ++I) { + // Check for sequences of digits. + if (isDigit(Data[I]) && isDigit(RHS.Data[I])) { + // The longer sequence of numbers is considered larger. + // This doesn't really handle prefixed zeros well. + size_t J; + for (J = I + 1; J != E + 1; ++J) { + bool ld = J < Length && isDigit(Data[J]); + bool rd = J < RHS.Length && isDigit(RHS.Data[J]); + if (ld != rd) + return rd ? -1 : 1; + if (!rd) + break; + } + // The two number sequences have the same length (J-I), just memcmp them. + if (int Res = compareMemory(Data + I, RHS.Data + I, J - I)) + return Res < 0 ? -1 : 1; + // Identical number sequences, continue search after the numbers. + I = J - 1; + continue; + } + if (Data[I] != RHS.Data[I]) + return (unsigned char)Data[I] < (unsigned char)RHS.Data[I] ? -1 : 1; + } + if (Length == RHS.Length) + return 0; + return Length < RHS.Length ? -1 : 1; +} + +// Compute the edit distance between the two given strings. +unsigned StringRef::edit_distance(llvm::StringRef Other, + bool AllowReplacements, + unsigned MaxEditDistance) const { + return llvm::ComputeEditDistance( + makeArrayRef(data(), size()), + makeArrayRef(Other.data(), Other.size()), + AllowReplacements, MaxEditDistance); +} + +//===----------------------------------------------------------------------===// +// String Operations +//===----------------------------------------------------------------------===// + +std::string StringRef::lower() const { + std::string Result(size(), char()); + for (size_type i = 0, e = size(); i != e; ++i) { + Result[i] = toLower(Data[i]); + } + return Result; +} + +std::string StringRef::upper() const { + std::string Result(size(), char()); + for (size_type i = 0, e = size(); i != e; ++i) { + Result[i] = toUpper(Data[i]); + } + return Result; +} + +//===----------------------------------------------------------------------===// +// String Searching +//===----------------------------------------------------------------------===// + + +/// find - Search for the first string \arg Str in the string. +/// +/// \return - The index of the first occurrence of \arg Str, or npos if not +/// found. +size_t StringRef::find(StringRef Str, size_t From) const { + if (From > Length) + return npos; + + const char *Start = Data + From; + size_t Size = Length - From; + + const char *Needle = Str.data(); + size_t N = Str.size(); + if (N == 0) + return From; + if (Size < N) + return npos; + if (N == 1) { + const char *Ptr = (const char *)::memchr(Start, Needle[0], Size); + return Ptr == nullptr ? npos : Ptr - Data; + } + + const char *Stop = Start + (Size - N + 1); + + // For short haystacks or unsupported needles fall back to the naive algorithm + if (Size < 16 || N > 255) { + do { + if (std::memcmp(Start, Needle, N) == 0) + return Start - Data; + ++Start; + } while (Start < Stop); + return npos; + } + + // Build the bad char heuristic table, with uint8_t to reduce cache thrashing. + uint8_t BadCharSkip[256]; + std::memset(BadCharSkip, N, 256); + for (unsigned i = 0; i != N-1; ++i) + BadCharSkip[(uint8_t)Str[i]] = N-1-i; + + do { + uint8_t Last = Start[N - 1]; + if (LLVM_UNLIKELY(Last == (uint8_t)Needle[N - 1])) + if (std::memcmp(Start, Needle, N - 1) == 0) + return Start - Data; + + // Otherwise skip the appropriate number of bytes. + Start += BadCharSkip[Last]; + } while (Start < Stop); + + return npos; +} + +size_t StringRef::find_lower(StringRef Str, size_t From) const { + StringRef This = substr(From); + while (This.size() >= Str.size()) { + if (This.startswith_lower(Str)) + return From; + This = This.drop_front(); + ++From; + } + return npos; +} + +size_t StringRef::rfind_lower(char C, size_t From) const { + From = std::min(From, Length); + size_t i = From; + while (i != 0) { + --i; + if (toLower(Data[i]) == toLower(C)) + return i; + } + return npos; +} + +/// rfind - Search for the last string \arg Str in the string. +/// +/// \return - The index of the last occurrence of \arg Str, or npos if not +/// found. +size_t StringRef::rfind(StringRef Str) const { + size_t N = Str.size(); + if (N > Length) + return npos; + for (size_t i = Length - N + 1, e = 0; i != e;) { + --i; + if (substr(i, N).equals(Str)) + return i; + } + return npos; +} + +size_t StringRef::rfind_lower(StringRef Str) const { + size_t N = Str.size(); + if (N > Length) + return npos; + for (size_t i = Length - N + 1, e = 0; i != e;) { + --i; + if (substr(i, N).equals_lower(Str)) + return i; + } + return npos; +} + +/// find_first_of - Find the first character in the string that is in \arg +/// Chars, or npos if not found. +/// +/// Note: O(size() + Chars.size()) +StringRef::size_type StringRef::find_first_of(StringRef Chars, + size_t From) const { + std::bitset<1 << CHAR_BIT> CharBits; + for (size_type i = 0; i != Chars.size(); ++i) + CharBits.set((unsigned char)Chars[i]); + + for (size_type i = std::min(From, Length), e = Length; i != e; ++i) + if (CharBits.test((unsigned char)Data[i])) + return i; + return npos; +} + +/// find_first_not_of - Find the first character in the string that is not +/// \arg C or npos if not found. +StringRef::size_type StringRef::find_first_not_of(char C, size_t From) const { + for (size_type i = std::min(From, Length), e = Length; i != e; ++i) + if (Data[i] != C) + return i; + return npos; +} + +/// find_first_not_of - Find the first character in the string that is not +/// in the string \arg Chars, or npos if not found. +/// +/// Note: O(size() + Chars.size()) +StringRef::size_type StringRef::find_first_not_of(StringRef Chars, + size_t From) const { + std::bitset<1 << CHAR_BIT> CharBits; + for (size_type i = 0; i != Chars.size(); ++i) + CharBits.set((unsigned char)Chars[i]); + + for (size_type i = std::min(From, Length), e = Length; i != e; ++i) + if (!CharBits.test((unsigned char)Data[i])) + return i; + return npos; +} + +/// find_last_of - Find the last character in the string that is in \arg C, +/// or npos if not found. +/// +/// Note: O(size() + Chars.size()) +StringRef::size_type StringRef::find_last_of(StringRef Chars, + size_t From) const { + std::bitset<1 << CHAR_BIT> CharBits; + for (size_type i = 0; i != Chars.size(); ++i) + CharBits.set((unsigned char)Chars[i]); + + for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i) + if (CharBits.test((unsigned char)Data[i])) + return i; + return npos; +} + +/// find_last_not_of - Find the last character in the string that is not +/// \arg C, or npos if not found. +StringRef::size_type StringRef::find_last_not_of(char C, size_t From) const { + for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i) + if (Data[i] != C) + return i; + return npos; +} + +/// find_last_not_of - Find the last character in the string that is not in +/// \arg Chars, or npos if not found. +/// +/// Note: O(size() + Chars.size()) +StringRef::size_type StringRef::find_last_not_of(StringRef Chars, + size_t From) const { + std::bitset<1 << CHAR_BIT> CharBits; + for (size_type i = 0, e = Chars.size(); i != e; ++i) + CharBits.set((unsigned char)Chars[i]); + + for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i) + if (!CharBits.test((unsigned char)Data[i])) + return i; + return npos; +} + +void StringRef::split(SmallVectorImpl &A, + StringRef Separator, int MaxSplit, + bool KeepEmpty) const { + StringRef S = *this; + + // Count down from MaxSplit. When MaxSplit is -1, this will just split + // "forever". This doesn't support splitting more than 2^31 times + // intentionally; if we ever want that we can make MaxSplit a 64-bit integer + // but that seems unlikely to be useful. + while (MaxSplit-- != 0) { + size_t Idx = S.find(Separator); + if (Idx == npos) + break; + + // Push this split. + if (KeepEmpty || Idx > 0) + A.push_back(S.slice(0, Idx)); + + // Jump forward. + S = S.slice(Idx + Separator.size(), npos); + } + + // Push the tail. + if (KeepEmpty || !S.empty()) + A.push_back(S); +} + +void StringRef::split(SmallVectorImpl &A, char Separator, + int MaxSplit, bool KeepEmpty) const { + StringRef S = *this; + + // Count down from MaxSplit. When MaxSplit is -1, this will just split + // "forever". This doesn't support splitting more than 2^31 times + // intentionally; if we ever want that we can make MaxSplit a 64-bit integer + // but that seems unlikely to be useful. + while (MaxSplit-- != 0) { + size_t Idx = S.find(Separator); + if (Idx == npos) + break; + + // Push this split. + if (KeepEmpty || Idx > 0) + A.push_back(S.slice(0, Idx)); + + // Jump forward. + S = S.slice(Idx + 1, npos); + } + + // Push the tail. + if (KeepEmpty || !S.empty()) + A.push_back(S); +} + +//===----------------------------------------------------------------------===// +// Helpful Algorithms +//===----------------------------------------------------------------------===// + +/// count - Return the number of non-overlapped occurrences of \arg Str in +/// the string. +size_t StringRef::count(StringRef Str) const { + size_t Count = 0; + size_t N = Str.size(); + if (N > Length) + return 0; + for (size_t i = 0, e = Length - N + 1; i != e; ++i) + if (substr(i, N).equals(Str)) + ++Count; + return Count; +} + +static unsigned GetAutoSenseRadix(StringRef &Str) { + if (Str.empty()) + return 10; + + if (Str.startswith("0x") || Str.startswith("0X")) { + Str = Str.substr(2); + return 16; + } + + if (Str.startswith("0b") || Str.startswith("0B")) { + Str = Str.substr(2); + return 2; + } + + if (Str.startswith("0o")) { + Str = Str.substr(2); + return 8; + } + + if (Str[0] == '0' && Str.size() > 1 && isDigit(Str[1])) { + Str = Str.substr(1); + return 8; + } + + return 10; +} + +bool llvm::consumeUnsignedInteger(StringRef &Str, unsigned Radix, + unsigned long long &Result) { + // Autosense radix if not specified. + if (Radix == 0) + Radix = GetAutoSenseRadix(Str); + + // Empty strings (after the radix autosense) are invalid. + if (Str.empty()) return true; + + // Parse all the bytes of the string given this radix. Watch for overflow. + StringRef Str2 = Str; + Result = 0; + while (!Str2.empty()) { + unsigned CharVal; + if (Str2[0] >= '0' && Str2[0] <= '9') + CharVal = Str2[0] - '0'; + else if (Str2[0] >= 'a' && Str2[0] <= 'z') + CharVal = Str2[0] - 'a' + 10; + else if (Str2[0] >= 'A' && Str2[0] <= 'Z') + CharVal = Str2[0] - 'A' + 10; + else + break; + + // If the parsed value is larger than the integer radix, we cannot + // consume any more characters. + if (CharVal >= Radix) + break; + + // Add in this character. + unsigned long long PrevResult = Result; + Result = Result * Radix + CharVal; + + // Check for overflow by shifting back and seeing if bits were lost. + if (Result / Radix < PrevResult) + return true; + + Str2 = Str2.substr(1); + } + + // We consider the operation a failure if no characters were consumed + // successfully. + if (Str.size() == Str2.size()) + return true; + + Str = Str2; + return false; +} + +bool llvm::consumeSignedInteger(StringRef &Str, unsigned Radix, + long long &Result) { + unsigned long long ULLVal; + + // Handle positive strings first. + if (Str.empty() || Str.front() != '-') { + if (consumeUnsignedInteger(Str, Radix, ULLVal) || + // Check for value so large it overflows a signed value. + (long long)ULLVal < 0) + return true; + Result = ULLVal; + return false; + } + + // Get the positive part of the value. + StringRef Str2 = Str.drop_front(1); + if (consumeUnsignedInteger(Str2, Radix, ULLVal) || + // Reject values so large they'd overflow as negative signed, but allow + // "-0". This negates the unsigned so that the negative isn't undefined + // on signed overflow. + (long long)-ULLVal > 0) + return true; + + Str = Str2; + Result = -ULLVal; + return false; +} + +/// GetAsUnsignedInteger - Workhorse method that converts a integer character +/// sequence of radix up to 36 to an unsigned long long value. +bool llvm::getAsUnsignedInteger(StringRef Str, unsigned Radix, + unsigned long long &Result) { + if (consumeUnsignedInteger(Str, Radix, Result)) + return true; + + // For getAsUnsignedInteger, we require the whole string to be consumed or + // else we consider it a failure. + return !Str.empty(); +} + +bool llvm::getAsSignedInteger(StringRef Str, unsigned Radix, + long long &Result) { + if (consumeSignedInteger(Str, Radix, Result)) + return true; + + // For getAsSignedInteger, we require the whole string to be consumed or else + // we consider it a failure. + return !Str.empty(); +} + +bool StringRef::getAsInteger(unsigned Radix, APInt &Result) const { + llvm_unreachable("getAsinteger"); +} + +bool StringRef::getAsDouble(double &Result, bool AllowInexact) const { + llvm_unreachable("getAsDouble"); +} + +// Implementation of StringRef hashing. +hash_code llvm::hash_value(StringRef S) { + return hash_combine_range(S.begin(), S.end()); +} -- cgit v1.2.3