зеркало из https://github.com/mozilla/gecko-dev.git
Bug 1875096 - Part 1: Only apply StepBackToLeadSurrogate for atom matches. r=iain
It's no longer necessary to adjust `lastIndex` before calling into irregexp, because irregexp has been fixed a while ago to correctly handle split surrogate pairs, cf. `v8::internal::RegExpCompiler::OptionallyStepBackToLeadSurrogate`. That means we only need to adjust `lastIndex` when performing atom matches, which allows to remove `StepBackToLeadSurrogate` from code-gen and move the corresponding C++ code from "builtin/RegExp.cpp" to "vm/RegExpObject.cpp". Differential Revision: https://phabricator.services.mozilla.com/D198821
This commit is contained in:
André Bargull
Родитель
16a6dcdaf3
Коммит
f33228184b
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@ -19,7 +19,6 @@
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#include "js/PropertySpec.h"
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#include "js/RegExpFlags.h" // JS::RegExpFlag, JS::RegExpFlags
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#include "util/StringBuffer.h"
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#include "util/Unicode.h"
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#include "vm/Interpreter.h"
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#include "vm/JSContext.h"
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#include "vm/RegExpObject.h"
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@ -1064,28 +1063,6 @@ const JSPropertySpec js::regexp_static_props[] = {
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JS_SELF_HOSTED_SYM_GET(species, "$RegExpSpecies", 0),
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JS_PS_END};
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template <typename CharT>
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static bool IsTrailSurrogateWithLeadSurrogateImpl(Handle<JSLinearString*> input,
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size_t index) {
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JS::AutoCheckCannotGC nogc;
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MOZ_ASSERT(index > 0 && index < input->length());
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const CharT* inputChars = input->chars<CharT>(nogc);
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return unicode::IsTrailSurrogate(inputChars[index]) &&
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unicode::IsLeadSurrogate(inputChars[index - 1]);
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}
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static bool IsTrailSurrogateWithLeadSurrogate(Handle<JSLinearString*> input,
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int32_t index) {
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if (index <= 0 || size_t(index) >= input->length()) {
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return false;
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}
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return input->hasLatin1Chars()
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? IsTrailSurrogateWithLeadSurrogateImpl<Latin1Char>(input, index)
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: IsTrailSurrogateWithLeadSurrogateImpl<char16_t>(input, index);
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}
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/*
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* ES 2017 draft rev 6a13789aa9e7c6de4e96b7d3e24d9e6eba6584ad 21.2.5.2.2
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* steps 3, 9-14, except 12.a.i, 12.c.i.1.
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@ -1122,36 +1099,7 @@ static RegExpRunStatus ExecuteRegExp(JSContext* cx, HandleObject regexp,
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/* Steps 4-8 performed by the caller. */
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/* Step 10. */
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if (reobj->unicode() || reobj->unicodeSets()) {
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/*
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* ES 2017 draft rev 6a13789aa9e7c6de4e96b7d3e24d9e6eba6584ad
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* 21.2.2.2 step 2.
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* Let listIndex be the index into Input of the character that was
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* obtained from element index of str.
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*
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* In the spec, pattern match is performed with decoded Unicode code
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* points, but our implementation performs it with UTF-16 encoded
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* string. In step 2, we should decrement lastIndex (index) if it
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* points the trail surrogate that has corresponding lead surrogate.
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*
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* var r = /\uD83D\uDC38/ug;
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* r.lastIndex = 1;
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* var str = "\uD83D\uDC38";
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* var result = r.exec(str); // pattern match starts from index 0
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* print(result.index); // prints 0
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*
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* Note: this doesn't match the current spec text and result in
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* different values for `result.index` under certain conditions.
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* However, the spec will change to match our implementation's
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* behavior. See https://github.com/tc39/ecma262/issues/128.
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*/
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if (IsTrailSurrogateWithLeadSurrogate(input, lastIndex)) {
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lastIndex--;
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}
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}
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/* Steps 3, 11-14, except 12.a.i, 12.c.i.1. */
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/* Steps 3, 10-14, except 12.a.i, 12.c.i.1. */
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RegExpRunStatus status =
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ExecuteRegExpImpl(cx, res, &re, input, lastIndex, matches);
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if (status == RegExpRunStatus_Error) {
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@ -1814,70 +1814,6 @@ static Address RegExpPairCountAddress(MacroAssembler& masm,
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MatchPairs::offsetOfPairCount());
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}
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// When the unicode flag is set, if lastIndex points to a trail
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// surrogate, we should step back to the corresponding lead surrogate.
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// See ExecuteRegExp in builtin/RegExp.cpp for more detail.
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static void StepBackToLeadSurrogate(MacroAssembler& masm, Register regexpShared,
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Register input, Register lastIndex,
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Register temp1, Register temp2) {
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Label done;
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// If neither unicode flag is set, there is nothing to do.
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masm.branchTest32(
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Assembler::Zero, Address(regexpShared, RegExpShared::offsetOfFlags()),
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Imm32(int32_t(JS::RegExpFlag::Unicode | JS::RegExpFlag::UnicodeSets)),
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&done);
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// If the input is latin1, there can't be any surrogates.
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masm.branchLatin1String(input, &done);
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// Check if |lastIndex > 0 && lastIndex < input->length()|.
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// lastIndex should already have no sign here.
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masm.branchTest32(Assembler::Zero, lastIndex, lastIndex, &done);
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masm.loadStringLength(input, temp1);
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masm.branch32(Assembler::AboveOrEqual, lastIndex, temp1, &done);
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// For TrailSurrogateMin ≤ x ≤ TrailSurrogateMax and
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// LeadSurrogateMin ≤ x ≤ LeadSurrogateMax, the following
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// equations hold.
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//
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// SurrogateMin ≤ x ≤ SurrogateMax
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// <> SurrogateMin ≤ x ≤ SurrogateMin + 2^10 - 1
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// <> ((x - SurrogateMin) >>> 10) = 0 where >>> is an unsigned-shift
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// See Hacker's Delight, section 4-1 for details.
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//
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// ((x - SurrogateMin) >>> 10) = 0
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// <> floor((x - SurrogateMin) / 1024) = 0
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// <> floor((x / 1024) - (SurrogateMin / 1024)) = 0
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// <> floor(x / 1024) = SurrogateMin / 1024
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// <> floor(x / 1024) * 1024 = SurrogateMin
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// <> (x >>> 10) << 10 = SurrogateMin
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// <> x & ~(2^10 - 1) = SurrogateMin
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constexpr char16_t SurrogateMask = 0xFC00;
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Register charsReg = temp1;
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masm.loadStringChars(input, charsReg, CharEncoding::TwoByte);
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// Check if input[lastIndex] is trail surrogate.
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masm.loadChar(charsReg, lastIndex, temp2, CharEncoding::TwoByte);
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masm.and32(Imm32(SurrogateMask), temp2);
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masm.branch32(Assembler::NotEqual, temp2, Imm32(unicode::TrailSurrogateMin),
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&done);
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// Check if input[lastIndex-1] is lead surrogate.
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masm.loadChar(charsReg, lastIndex, temp2, CharEncoding::TwoByte,
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-int32_t(sizeof(char16_t)));
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masm.and32(Imm32(SurrogateMask), temp2);
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masm.branch32(Assembler::NotEqual, temp2, Imm32(unicode::LeadSurrogateMin),
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&done);
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// Move lastIndex back to lead surrogate.
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masm.sub32(Imm32(1), lastIndex);
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masm.bind(&done);
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}
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static void UpdateRegExpStatics(MacroAssembler& masm, Register regexp,
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Register input, Register lastIndex,
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Register staticsReg, Register temp1,
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@ -2067,9 +2003,6 @@ static bool PrepareAndExecuteRegExp(MacroAssembler& masm, Register regexp,
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masm.branchTestUndefined(Assembler::Equal, sharedSlot, failure);
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masm.unboxNonDouble(sharedSlot, regexpReg, JSVAL_TYPE_PRIVATE_GCTHING);
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// Update lastIndex if necessary.
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StepBackToLeadSurrogate(masm, regexpReg, input, lastIndex, temp2, temp3);
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// Handle Atom matches
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Label notAtom, checkSuccess;
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masm.branchPtr(Assembler::Equal,
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@ -23,6 +23,7 @@
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#include "js/RegExp.h"
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#include "js/RegExpFlags.h" // JS::RegExpFlags
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#include "util/StringBuffer.h"
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#include "util/Unicode.h"
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#include "vm/MatchPairs.h"
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#include "vm/PlainObject.h"
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#include "vm/RegExpStatics.h"
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@ -782,12 +783,57 @@ bool RegExpShared::markedForTierUp() const {
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return ticks_ == 0;
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}
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// When either unicode flag is set and if |index| points to a trail surrogate,
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// step back to the corresponding lead surrogate.
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static size_t StepBackToLeadSurrogate(const JSLinearString* input,
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size_t index) {
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// |index| must be a position within a two-byte string, otherwise it can't
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// point to the trail surrogate of a surrogate pair.
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if (index == 0 || index >= input->length() || input->hasLatin1Chars()) {
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return index;
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}
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/*
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* ES 2017 draft rev 6a13789aa9e7c6de4e96b7d3e24d9e6eba6584ad
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* 21.2.2.2 step 2.
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* Let listIndex be the index into Input of the character that was obtained
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* from element index of str.
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*
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* In the spec, pattern match is performed with decoded Unicode code points,
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* but our implementation performs it with UTF-16 encoded strings. In step 2,
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* we should decrement lastIndex (index) if it points to a trail surrogate
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* that has a corresponding lead surrogate.
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*
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* var r = /\uD83D\uDC38/ug;
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* r.lastIndex = 1;
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* var str = "\uD83D\uDC38";
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* var result = r.exec(str); // pattern match starts from index 0
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* print(result.index); // prints 0
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*
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* Note: This doesn't match the current spec text and result in different
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* values for `result.index` under certain conditions. However, the spec will
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* change to match our implementation's behavior.
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* See https://github.com/tc39/ecma262/issues/128.
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*/
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JS::AutoCheckCannotGC nogc;
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const auto* chars = input->twoByteChars(nogc);
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if (unicode::IsTrailSurrogate(chars[index]) &&
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unicode::IsLeadSurrogate(chars[index - 1])) {
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index--;
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}
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return index;
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}
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static RegExpRunStatus ExecuteAtomImpl(RegExpShared* re, JSLinearString* input,
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size_t start, MatchPairs* matches) {
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MOZ_ASSERT(re->pairCount() == 1);
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size_t length = input->length();
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size_t searchLength = re->patternAtom()->length();
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if (re->unicode() || re->unicodeSets()) {
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start = StepBackToLeadSurrogate(input, start);
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}
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if (re->sticky()) {
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// First part checks size_t overflow.
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if (searchLength + start < searchLength || searchLength + start > length) {
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