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[lldb] Add type summary for String.Index (#5515)
Implement a type summary for Swift's `String.Index`. The summary string follows the following: 1. Original proposal: https://forums.swift.org/t/improving-string-index-s-printed-descriptions/57027 2. Proposed implementation: swiftlang/swift#58479 3. Temporary(ish) near-`CustomStringConvertible` implementation: swiftlang/swift#61548 The associated test cases are taken from the test cases in swiftlang/swift#58479. rdar://99211823 (cherry picked from commit c7146a3)
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‎lldb/source/Plugins/Language/Swift/SwiftFormatters.cpp

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@@ -11,11 +11,13 @@
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//===----------------------------------------------------------------------===//
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#include "SwiftFormatters.h"
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#include "Plugins/Language/Swift/SwiftStringIndex.h"
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#include "Plugins/LanguageRuntime/Swift/SwiftLanguageRuntime.h"
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#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
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#include "lldb/DataFormatters/FormattersHelpers.h"
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#include "lldb/DataFormatters/StringPrinter.h"
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#include "lldb/Target/Process.h"
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#include "lldb/Utility/ConstString.h"
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#include "lldb/Utility/DataBufferHeap.h"
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#include "lldb/Utility/Status.h"
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#include "lldb/Utility/Timer.h"
@@ -368,6 +370,26 @@ bool lldb_private::formatters::swift::String_SummaryProvider(
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return false;
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}
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bool lldb_private::formatters::swift::StringIndex_SummaryProvider(
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ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
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static ConstString g__rawBits("_rawBits");
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auto raw_bits_sp = valobj.GetChildMemberWithName(g__rawBits, true);
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if (!raw_bits_sp)
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return false;
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bool success = false;
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StringIndex index =
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raw_bits_sp->GetSyntheticValue()->GetValueAsUnsigned(0, &success);
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if (!success)
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return false;
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stream.Printf("%llu[%s]", index.encodedOffset(), index.encodingName());
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if (index.transcodedOffset() != 0)
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stream.Printf("+%u", index.transcodedOffset());
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return true;
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}
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bool lldb_private::formatters::swift::StaticString_SummaryProvider(
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ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
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return StaticString_SummaryProvider(

‎lldb/source/Plugins/Language/Swift/SwiftFormatters.h

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@@ -54,6 +54,9 @@ bool String_SummaryProvider(ValueObject &valobj, Stream &stream,
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const TypeSummaryOptions &,
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StringPrinter::ReadStringAndDumpToStreamOptions);
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bool StringIndex_SummaryProvider(ValueObject &valobj, Stream &stream,
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const TypeSummaryOptions &options);
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bool StaticString_SummaryProvider(ValueObject &valobj, Stream &stream,
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const TypeSummaryOptions &options);
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‎lldb/source/Plugins/Language/Swift/SwiftLanguage.cpp

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@@ -418,6 +418,10 @@ static void LoadSwiftFormatters(lldb::TypeCategoryImplSP swift_category_sp) {
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AddCXXSummary(swift_category_sp, string_summary_provider,
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"Swift.String summary provider", ConstString("Swift.String"),
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summary_flags);
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AddCXXSummary(swift_category_sp,
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lldb_private::formatters::swift::StringIndex_SummaryProvider,
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"Swift String.Index summary provider",
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ConstString("Swift.String.Index"), summary_flags);
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bool (*staticstring_summary_provider)(ValueObject &, Stream &,
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const TypeSummaryOptions &) =
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lldb_private::formatters::swift::StaticString_SummaryProvider;

‎lldb/source/Plugins/Language/Swift/SwiftStringIndex.h

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@@ -0,0 +1,65 @@
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//===-- SwiftStringIndex.h --------------------------------------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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#ifndef liblldb_SwiftStringIndex_h
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#define liblldb_SwiftStringIndex_h
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#include "lldb/lldb-forward.h"
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namespace lldb_private {
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namespace formatters {
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namespace swift {
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// From SwiftIndex.swift
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// ┌──────────┬────────────────╥────────────────┬───────╥───────┐
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// │ b63:b16 │ b15:b14 ║ b13:b8 │ b7:b4 ║ b3:b0 │
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// ├──────────┼────────────────╫────────────────┼───────╫───────┤
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// │ position │ transc. offset ║ grapheme cache │ rsvd ║ flags │
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// └──────────┴────────────────╨────────────────┴───────╨───────┘
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// └────── resilient ───────┘
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class StringIndex {
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uint64_t _rawBits;
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enum Flags : uint8_t {
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IsScalarAligned = 1 << 0,
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IsCharacterAligned = 1 << 1,
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CanBeUTF8 = 1 << 2,
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CanBeUTF16 = 1 << 3,
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};
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public:
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StringIndex(uint64_t rawBits) : _rawBits(rawBits) {}
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uint64_t encodedOffset() { return _rawBits >> 16; }
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const char *encodingName() {
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uint8_t flags = _rawBits & 0b1111;
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bool canBeUTF8 = flags & Flags::CanBeUTF8;
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bool canBeUTF16 = flags & Flags::CanBeUTF16;
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if (canBeUTF8 && canBeUTF16)
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return "any";
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else if (canBeUTF8)
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return "utf8";
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else if (canBeUTF16)
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return "utf16";
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else
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return "unknown";
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}
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uint8_t transcodedOffset() { return (_rawBits >> 14) & 0b11; }
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};
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}; // namespace swift
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}; // namespace formatters
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}; // namespace lldb_private
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#endif

‎lldb/test/API/functionalities/data-formatter/swift/string-index/Makefile

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SWIFT_SOURCES := main.swift
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include Makefile.rules

‎lldb/test/API/functionalities/data-formatter/swift/string-index/TestSwiftStringIndexFormatters.py

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"""
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Test String.Index summary strings.
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The test cases are LLDB versions of the original Swift tests, see
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https://github.com/apple/swift/pull/58479
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"""
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import lldb
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from lldbsuite.test.lldbtest import *
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from lldbsuite.test.decorators import *
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import lldbsuite.test.lldbutil as lldbutil
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class TestCase(TestBase):
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@skipUnlessFoundation
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@swiftTest
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def test_swift_string_index_formatters(self):
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"""Test String.Index summary strings."""
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self.build()
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_, process, _, _ = lldbutil.run_to_source_breakpoint(
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self, "break here", lldb.SBFileSpec("main.swift")
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)
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#
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# The first breakpoint stop tests a native (non-bridged) String.
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#
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self.expect(
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"v nativeIndices",
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substrs=[
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"0[any]",
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"1[utf8]",
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"9[utf8]",
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"10[utf8]",
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],
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)
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self.expect(
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"v unicodeScalarIndices",
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substrs=[
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"0[any]",
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"1[utf8]",
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"5[utf8]",
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"9[utf8]",
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"10[utf8]",
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],
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)
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self.expect(
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"v utf8Indices",
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substrs=[
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"0[any]",
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"1[utf8]",
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"2[utf8]",
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"3[utf8]",
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"4[utf8]",
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"5[utf8]",
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"6[utf8]",
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"7[utf8]",
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"8[utf8]",
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"9[utf8]",
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"10[utf8]",
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],
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)
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self.expect(
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"v utf16Indices",
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substrs=[
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"0[any]",
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"1[utf8]",
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"1[utf8]+1",
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"5[utf8]",
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"5[utf8]+1",
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"9[utf8]",
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"10[utf8]",
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],
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)
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#
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# The second breakpoint stop tests a bridged String.
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#
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process.Continue()
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self.expect(
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"v nativeIndices",
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substrs=[
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"0[any]",
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"1[utf16]",
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"5[utf16]",
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"6[utf16]",
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],
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)
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self.expect(
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"v unicodeScalarIndices",
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substrs=[
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"0[any]",
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"1[utf16]",
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"3[utf16]",
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"5[utf16]",
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"6[utf16]",
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],
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)
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self.expect(
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"v utf8Indices",
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substrs=[
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"0[any]",
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"1[utf16]",
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"1[utf16]+1",
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"1[utf16]+2",
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"1[utf16]+3",
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"3[utf16]",
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"3[utf16]+1",
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"3[utf16]+2",
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"3[utf16]+3",
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"5[utf16]",
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"6[utf16]",
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],
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)
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self.expect(
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"v utf16Indices",
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substrs=[
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"0[any]",
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"1[utf16]",
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"2[utf16]",
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"3[utf16]",
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"4[utf16]",
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"5[utf16]",
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"6[utf16]",
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],
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)

‎lldb/test/API/functionalities/data-formatter/swift/string-index/main.swift

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import Foundation
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func main() {
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exerciseNative()
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exerciseBridged()
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}
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func exerciseNative() {
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exercise("a👉🏼b")
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}
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func exerciseBridged() {
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exercise("a👉🏼b" as NSString as String)
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}
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func exercise(_ string: String) {
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let nativeIndices = allIndices(string)
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let unicodeScalarIndices = allIndices(string.unicodeScalars)
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let utf8Indices = allIndices(string.utf8)
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let utf16Indices = allIndices(string.utf16)
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// break here
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}
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func allIndices<T: Collection>(_ collection: T) -> [T.Index] {
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return Array(collection.indices) + [collection.endIndex]
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}
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main()

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