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[StrTable] Use string literal emission for intrinsics on non-MSVC platforms #124856

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4 changes: 3 additions & 1 deletion llvm/cmake/modules/TableGen.cmake
Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,9 @@ function(tablegen project ofn)
# char literals, instead. If we're cross-compiling, then conservatively assume
# that the source might be consumed by MSVC.
# [1] https://docs.microsoft.com/en-us/cpp/cpp/compiler-limits?view=vs-2017
if (MSVC AND project STREQUAL LLVM)
# Don't pass this flag to mlir-src-sharder, since it doesn't support the
# flag, and it doesn't need it.
if (MSVC AND NOT "${project}" STREQUAL "MLIR_SRC_SHARDER")
list(APPEND LLVM_TABLEGEN_FLAGS "--long-string-literals=0")
endif()
if (CMAKE_GENERATOR MATCHES "Visual Studio")
Expand Down
5 changes: 5 additions & 0 deletions llvm/include/llvm/TableGen/Main.h
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@
#ifndef LLVM_TABLEGEN_MAIN_H
#define LLVM_TABLEGEN_MAIN_H

#include "llvm/Support/CommandLine.h"
#include <functional>

namespace llvm {
Expand All @@ -27,6 +28,10 @@ using TableGenMainFn = bool(raw_ostream &OS, const RecordKeeper &Records);
int TableGenMain(const char *argv0,
std::function<TableGenMainFn> MainFn = nullptr);

/// Controls emitting large character arrays as strings or character arrays.
/// Typically set to false when building with MSVC.
extern cl::opt<bool> EmitLongStrLiterals;

} // end namespace llvm

#endif // LLVM_TABLEGEN_MAIN_H
104 changes: 3 additions & 101 deletions llvm/include/llvm/TableGen/StringToOffsetTable.h
Original file line number Diff line number Diff line change
Expand Up @@ -12,8 +12,6 @@
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/raw_ostream.h"
#include <optional>

namespace llvm {
Expand All @@ -36,17 +34,7 @@ class StringToOffsetTable {
bool empty() const { return StringOffset.empty(); }
size_t size() const { return AggregateString.size(); }

unsigned GetOrAddStringOffset(StringRef Str, bool appendZero = true) {
auto [II, Inserted] = StringOffset.insert({Str, size()});
if (Inserted) {
// Add the string to the aggregate if this is the first time found.
AggregateString.append(Str.begin(), Str.end());
if (appendZero)
AggregateString += '\0';
}

return II->second;
}
unsigned GetOrAddStringOffset(StringRef Str, bool appendZero = true);

// Returns the offset of `Str` in the table if its preset, else return
// std::nullopt.
Expand All @@ -69,96 +57,10 @@ class StringToOffsetTable {
// `static` and `constexpr`. Both `Name` and (`Name` + "Storage") must be
// valid identifiers to declare.
void EmitStringTableDef(raw_ostream &OS, const Twine &Name,
const Twine &Indent = "") const {
OS << formatv(R"(
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Woverlength-strings"
#endif
{0}static constexpr char {1}Storage[] = )",
Indent, Name);

// MSVC silently miscompiles string literals longer than 64k in some
// circumstances. When the string table is longer, emit it as an array of
// character literals.
bool UseChars = AggregateString.size() > (64 * 1024);
OS << (UseChars ? "{\n" : "\n");

llvm::ListSeparator LineSep(UseChars ? ",\n" : "\n");
llvm::SmallVector<StringRef> Strings(split(AggregateString, '\0'));
// We should always have an empty string at the start, and because these are
// null terminators rather than separators, we'll have one at the end as
// well. Skip the end one.
assert(Strings.front().empty() && "Expected empty initial string!");
assert(Strings.back().empty() &&
"Expected empty string at the end due to terminators!");
Strings.pop_back();
for (StringRef Str : Strings) {
OS << LineSep << Indent << " ";
// If we can, just emit this as a string literal to be concatenated.
if (!UseChars) {
OS << "\"";
OS.write_escaped(Str);
OS << "\\0\"";
continue;
}

llvm::ListSeparator CharSep(", ");
for (char C : Str) {
OS << CharSep << "'";
OS.write_escaped(StringRef(&C, 1));
OS << "'";
}
OS << CharSep << "'\\0'";
}
OS << LineSep << Indent << (UseChars ? "};" : " ;");

OS << formatv(R"(
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif

{0}static constexpr llvm::StringTable {1} =
{0} {1}Storage;
)",
Indent, Name);
}
const Twine &Indent = "") const;

// Emit the string as one single string.
void EmitString(raw_ostream &O) const {
// Escape the string.
SmallString<256> EscapedStr;
raw_svector_ostream(EscapedStr).write_escaped(AggregateString);

O << " \"";
unsigned CharsPrinted = 0;
for (unsigned i = 0, e = EscapedStr.size(); i != e; ++i) {
if (CharsPrinted > 70) {
O << "\"\n \"";
CharsPrinted = 0;
}
O << EscapedStr[i];
++CharsPrinted;

// Print escape sequences all together.
if (EscapedStr[i] != '\\')
continue;

assert(i + 1 < EscapedStr.size() && "Incomplete escape sequence!");
if (isDigit(EscapedStr[i + 1])) {
assert(isDigit(EscapedStr[i + 2]) && isDigit(EscapedStr[i + 3]) &&
"Expected 3 digit octal escape!");
O << EscapedStr[++i];
O << EscapedStr[++i];
O << EscapedStr[++i];
CharsPrinted += 3;
} else {
O << EscapedStr[++i];
++CharsPrinted;
}
}
O << "\"";
}
void EmitString(raw_ostream &O) const;
};

} // end namespace llvm
Expand Down
1 change: 1 addition & 0 deletions llvm/lib/TableGen/CMakeLists.txt
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@ add_llvm_component_library(LLVMTableGen
Record.cpp
SetTheory.cpp
StringMatcher.cpp
StringToOffsetTable.cpp
TableGenBackend.cpp
TableGenBackendSkeleton.cpp
TGLexer.cpp
Expand Down
9 changes: 9 additions & 0 deletions llvm/lib/TableGen/Main.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,15 @@ WriteIfChanged("write-if-changed", cl::desc("Only write output if it changed"));
static cl::opt<bool>
TimePhases("time-phases", cl::desc("Time phases of parser and backend"));

namespace llvm {
cl::opt<bool> EmitLongStrLiterals(
"long-string-literals",
cl::desc("when emitting large string tables, prefer string literals over "
"comma-separated char literals. This can be a readability and "
"compile-time performance win, but upsets some compilers"),
cl::Hidden, cl::init(true));
} // end namespace llvm

static cl::opt<bool> NoWarnOnUnusedTemplateArgs(
"no-warn-on-unused-template-args",
cl::desc("Disable unused template argument warnings."));
Expand Down
120 changes: 120 additions & 0 deletions llvm/lib/TableGen/StringToOffsetTable.cpp
Original file line number Diff line number Diff line change
@@ -0,0 +1,120 @@
//===- StringToOffsetTable.cpp - Emit a big concatenated string -*- C++ -*-===//
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(Note that the updated coding standard doesn't require this line to contain filename/description/c++.)

//
// 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/TableGen/StringToOffsetTable.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TableGen/Main.h"

using namespace llvm;

unsigned StringToOffsetTable::GetOrAddStringOffset(StringRef Str,
bool appendZero) {
auto [II, Inserted] = StringOffset.insert({Str, size()});
if (Inserted) {
// Add the string to the aggregate if this is the first time found.
AggregateString.append(Str.begin(), Str.end());
if (appendZero)
AggregateString += '\0';
}

return II->second;
}

void StringToOffsetTable::EmitStringTableDef(raw_ostream &OS, const Twine &Name,
const Twine &Indent) const {
OS << formatv(R"(
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Woverlength-strings"
#endif
{0}static constexpr char {1}Storage[] = )",
Indent, Name);

// MSVC silently miscompiles string literals longer than 64k in some
// circumstances. The build system sets EmitLongStrLiterals to false when it
// detects that it is targetting MSVC. When that option is false and the
// string table is longer than 64k, emit it as an array of character
// literals.
bool UseChars = !EmitLongStrLiterals && AggregateString.size() > (64 * 1024);
OS << (UseChars ? "{\n" : "\n");

llvm::ListSeparator LineSep(UseChars ? ",\n" : "\n");
llvm::SmallVector<StringRef> Strings(split(AggregateString, '\0'));
// We should always have an empty string at the start, and because these are
// null terminators rather than separators, we'll have one at the end as
// well. Skip the end one.
assert(Strings.front().empty() && "Expected empty initial string!");
assert(Strings.back().empty() &&
"Expected empty string at the end due to terminators!");
Strings.pop_back();
for (StringRef Str : Strings) {
OS << LineSep << Indent << " ";
// If we can, just emit this as a string literal to be concatenated.
if (!UseChars) {
OS << "\"";
OS.write_escaped(Str);
OS << "\\0\"";
continue;
}

llvm::ListSeparator CharSep(", ");
for (char C : Str) {
OS << CharSep << "'";
OS.write_escaped(StringRef(&C, 1));
OS << "'";
}
OS << CharSep << "'\\0'";
}
OS << LineSep << Indent << (UseChars ? "};" : " ;");

OS << formatv(R"(
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif

{0}static constexpr llvm::StringTable {1} =
{0} {1}Storage;
)",
Indent, Name);
}

void StringToOffsetTable::EmitString(raw_ostream &O) const {
// Escape the string.
SmallString<256> EscapedStr;
raw_svector_ostream(EscapedStr).write_escaped(AggregateString);

O << " \"";
unsigned CharsPrinted = 0;
for (unsigned i = 0, e = EscapedStr.size(); i != e; ++i) {
if (CharsPrinted > 70) {
O << "\"\n \"";
CharsPrinted = 0;
}
O << EscapedStr[i];
++CharsPrinted;

// Print escape sequences all together.
if (EscapedStr[i] != '\\')
continue;

assert(i + 1 < EscapedStr.size() && "Incomplete escape sequence!");
if (isDigit(EscapedStr[i + 1])) {
assert(isDigit(EscapedStr[i + 2]) && isDigit(EscapedStr[i + 3]) &&
"Expected 3 digit octal escape!");
O << EscapedStr[++i];
O << EscapedStr[++i];
O << EscapedStr[++i];
CharsPrinted += 3;
} else {
O << EscapedStr[++i];
++CharsPrinted;
}
}
O << "\"";
}
1 change: 1 addition & 0 deletions llvm/utils/TableGen/AsmMatcherEmitter.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -110,6 +110,7 @@
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include "llvm/TableGen/StringMatcher.h"
Expand Down
3 changes: 1 addition & 2 deletions llvm/utils/TableGen/Basic/SequenceToOffsetTable.h
Original file line number Diff line number Diff line change
Expand Up @@ -15,15 +15,14 @@
#define LLVM_UTILS_TABLEGEN_BASIC_SEQUENCETOOFFSETTABLE_H

#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TableGen/Main.h"
#include <algorithm>
#include <cassert>
#include <functional>
#include <map>

namespace llvm {
extern cl::opt<bool> EmitLongStrLiterals;

inline void printChar(raw_ostream &OS, char C) {
unsigned char UC(C);
Expand Down
9 changes: 0 additions & 9 deletions llvm/utils/TableGen/Basic/TableGen.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -26,15 +26,6 @@

using namespace llvm;

namespace llvm {
cl::opt<bool> EmitLongStrLiterals(
"long-string-literals",
cl::desc("when emitting large string tables, prefer string literals over "
"comma-separated char literals. This can be a readability and "
"compile-time performance win, but upsets some compilers"),
cl::Hidden, cl::init(true));
} // end namespace llvm

static cl::OptionCategory PrintEnumsCat("Options for -print-enums");
static cl::opt<std::string> Class("class",
cl::desc("Print Enum list for this class"),
Expand Down
1 change: 1 addition & 0 deletions llvm/utils/TableGen/SDNodeInfoEmitter.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
#include "Basic/SequenceToOffsetTable.h"
#include "Common/CodeGenDAGPatterns.h" // For SDNodeInfo.
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/StringToOffsetTable.h"
#include "llvm/TableGen/TableGenBackend.h"
Expand Down
1 change: 1 addition & 0 deletions llvm/utils/gn/secondary/llvm/lib/TableGen/BUILD.gn
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@ static_library("TableGen") {
"Record.cpp",
"SetTheory.cpp",
"StringMatcher.cpp",
"StringToOffsetTable.cpp",
"TGLexer.cpp",
"TGParser.cpp",
"TGTimer.cpp",
Expand Down