[includes] Reduce IWYU exports from SkTypes.h

SkTypes.h was found exporting <stddef.h> and <stdint.h>.
Thus if a Skia file includes SkTypes.h, it did not need
to include either of those files to use things like
size_t or uint8_t respectively. [1]

This also resulted in strange IWYU warnings like:
warning: size_t is defined in "include/core/SkTypes.h", which isn't directly #included.

Thus, this CL removes those additional exports, and as a result,
adds many more includes of <cstddef> and <cstdint>.

The second change this CL is to not use the default IWYU
mappings which are hard-coded into IWYU [2]. These defaults
are valid, but make suggestions for the C version of
headers and not the C++ ones (i.e. <stddef.h> over <cstddef>).

To make these recommendations align better with our preferred
style (the C++ ones), we use IWYU with --no_default_mappings
and then have to expand our existing mappings to better deal
with how IWYU would resolve some of these headers.

[1] https://codereview.chromium.org/1207893002/#msg49
[2] 4c0f396159/iwyu_include_picker.cc (L1221-L1234)

Change-Id: Iafebe190f8f3e86f252147b9f538c182bcc34af4
Bug: skia:13052
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/555516
Auto-Submit: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

include/core/SkTypes.h

@@ -193,9 +193,9 @@
 #else
     #include "include/config/SkUserConfig.h"
 #endif
+// IWYU pragma: end_exports
 #include <stddef.h>
 #include <stdint.h>
-// IWYU pragma: end_exports
 
 // Post SkUserConfig.h checks and such.
 #if !defined(SK_DEBUG) && !defined(SK_RELEASE)

include/sksl/DSLType.h

@@ -14,6 +14,7 @@
 #include "include/sksl/DSLModifiers.h"
 #include "include/sksl/SkSLPosition.h"
 
+#include <cstdint>
 #include <string_view>
 #include <utility>
 

include/sksl/DSLVar.h

@@ -14,7 +14,7 @@
 #include "include/sksl/DSLType.h"
 #include "include/sksl/SkSLPosition.h"
 
-#include <stdint.h>
+#include <cstdint>
 #include <memory>
 #include <string_view>
 #include <utility>

include/sksl/SkSLPosition.h

@@ -9,6 +9,8 @@
 #define SKSL_POSITION
 
 #include "include/core/SkTypes.h"
+
+#include <cstdint>
 #include <string_view>
 
 namespace SkSL {

include/utils/SkAnimCodecPlayer.h

@@ -13,7 +13,7 @@
 #include "include/core/SkRefCnt.h"
 #include "include/core/SkSize.h"
 
-#include <stdint.h>
+#include <cstdint>
 #include <memory>
 #include <vector>
 

include/utils/SkBase64.h

@@ -10,6 +10,8 @@
 
 #include "include/core/SkTypes.h"
 
+#include <cstddef>
+
 struct SkBase64 {
 public:
     enum Error {

include/utils/SkEventTracer.h

@@ -18,6 +18,8 @@
 
 #include "include/core/SkTypes.h"
 
+#include <cstdint>
+
 class SK_API SkEventTracer {
 public:
 

include/utils/SkNWayCanvas.h

@@ -22,6 +22,8 @@
 #include "include/private/SkTDArray.h"
 #include "include/utils/SkNoDrawCanvas.h"
 
+#include <cstddef>
+
 namespace sktext {
 class GlyphRunList;
 }

include/utils/SkPaintFilterCanvas.h

@@ -21,6 +21,8 @@
 #include "include/private/SkTDArray.h"
 #include "include/utils/SkNWayCanvas.h"
 
+#include <cstddef>
+
 namespace sktext {
 class GlyphRunList;
 }

include/utils/SkParse.h

@@ -14,6 +14,9 @@
 #include "include/core/SkScalar.h"
 #include "include/core/SkTypes.h"
 
+#include <cstddef>
+#include <cstdint>
+
 class SK_API SkParse {
 public:
     static int Count(const char str[]); // number of scalars or int values

include/utils/SkShadowUtils.h

@@ -13,6 +13,8 @@
 #include "include/core/SkTypes.h"
 #include "include/private/SkShadowFlags.h"
 
+#include <cstdint>
+
 class SkCanvas;
 class SkMatrix;
 class SkPath;

include/utils/SkTextUtils.h

@@ -12,7 +12,8 @@
 #include "include/core/SkScalar.h"
 #include "include/core/SkTypes.h"
 
-#include <string.h>
+#include <cstddef>
+#include <string>
 
 class SkCanvas;
 class SkFont;

src/sksl/SkSLAnalysis.h

@@ -11,7 +11,7 @@
 #include "include/private/SkSLSampleUsage.h"
 #include "include/private/SkTArray.h"
 
-#include <stdint.h>
+#include <cstdint>
 #include <memory>
 #include <set>
 

src/sksl/SkSLCompiler.h

@@ -22,6 +22,8 @@
 #include "src/sksl/ir/SkSLProgram.h"
 
 #include <array>
+#include <cstddef>
+#include <cstdint>
 #include <memory>
 #include <string>
 #include <string_view>

src/sksl/SkSLConstantFolder.cpp

@@ -24,6 +24,7 @@
 #include "src/sksl/ir/SkSLVariableReference.h"
 
 #include <cmath>
+#include <cstdint>
 #include <limits>
 #include <optional>
 #include <string>

src/sksl/SkSLDSLParser.cpp

@@ -30,6 +30,7 @@
 #include "src/sksl/ir/SkSLProgram.h"
 
 #include <algorithm>
+#include <climits>
 #include <initializer_list>
 #include <memory>
 #include <type_traits>

src/sksl/SkSLDSLParser.h

@@ -25,6 +25,7 @@
 #include "src/sksl/SkSLLexer.h"
 #include "src/sksl/SkSLProgramSettings.h"
 
+#include <cstddef>
 #include <memory>
 #include <optional>
 #include <string>

src/sksl/SkSLInliner.cpp

@@ -59,6 +59,7 @@
 
 #include <algorithm>
 #include <climits>
+#include <cstddef>
 #include <memory>
 #include <string>
 #include <string_view>

src/sksl/SkSLOutputStream.h

@@ -10,7 +10,9 @@
 
 #include "include/core/SkTypes.h"
 
-#include <stdarg.h>
+#include <cstdarg>
+#include <cstddef>
+#include <cstdint>
 #include <string>
 
 namespace SkSL {

src/sksl/SkSLPool.h

@@ -10,7 +10,7 @@
 
 #include "src/sksl/SkSLMemoryPool.h"
 
-#include <stddef.h>
+#include <cstddef>
 #include <memory>
 
 namespace SkSL {

src/sksl/SkSLRehydrator.h

@@ -15,6 +15,8 @@
 #include "src/sksl/SkSLContext.h"
 #include "src/sksl/ir/SkSLSymbolTable.h"
 
+#include <cstddef>
+#include <cstdint>
 #include <memory>
 #include <string_view>
 #include <string>

src/sksl/SkSLString.cpp

@@ -7,13 +7,13 @@
 
 #include "include/private/SkSLString.h"
 
+#include <cerrno>
 #include <cmath>
-#include <errno.h>
+#include <cstdio>
+#include <cstdlib>
 #include <locale>
 #include <memory>
 #include <sstream>
-#include <stdio.h>
-#include <stdlib.h>
 #include <string>
 
 std::string skstd::to_string(float value) {

src/sksl/analysis/SkSLFinalizationChecks.cpp

@@ -30,6 +30,7 @@
 #include "src/sksl/ir/SkSLVarDeclarations.h"
 #include "src/sksl/ir/SkSLVariable.h"
 
+#include <cstddef>
 #include <cstdint>
 #include <memory>
 #include <string>

src/sksl/analysis/SkSLIsSameExpressionTree.cpp

@@ -21,6 +21,7 @@
 #include "src/sksl/ir/SkSLType.h"
 #include "src/sksl/ir/SkSLVariableReference.h"
 
+#include <cstddef>
 #include <memory>
 
 namespace SkSL {

src/sksl/codegen/SkSLMetalCodeGenerator.cpp

@@ -63,6 +63,7 @@
 #include "src/sksl/spirv.h"
 
 #include <algorithm>
+#include <cstddef>
 #include <functional>
 #include <limits>
 #include <memory>

src/sksl/codegen/SkSLMetalCodeGenerator.h

@@ -16,7 +16,7 @@
 #include "src/sksl/codegen/SkSLCodeGenerator.h"
 #include "src/sksl/ir/SkSLType.h"
 
-#include <stdint.h>
+#include <cstdint>
 #include <initializer_list>
 #include <set>
 #include <string>

src/sksl/codegen/SkSLSPIRVCodeGenerator.cpp

@@ -68,6 +68,7 @@
 
 #include <cmath>
 #include <set>
+#include <string>
 #include <type_traits>
 #include <utility>
 

src/sksl/codegen/SkSLSPIRVCodeGenerator.h

@@ -25,10 +25,10 @@
 #include "src/sksl/ir/SkSLVariable.h"
 #include "src/sksl/spirv.h"
 
+#include <cstddef>
 #include <cstdint>
 #include <memory>
 #include <stack>
-#include <string>
 #include <string_view>
 #include <vector>
 

src/sksl/codegen/SkSLVMCodeGenerator.cpp

@@ -62,7 +62,7 @@
 #include "src/sksl/tracing/SkVMDebugTrace.h"
 
 #include <algorithm>
-#include <cstddef>
+#include <cstdint>
 #include <functional>
 #include <iterator>
 #include <string_view>

src/sksl/codegen/SkSLVMCodeGenerator.h

@@ -11,6 +11,7 @@
 #include "src/core/SkVM.h"
 #include "src/sksl/ir/SkSLType.h"
 
+#include <cstddef>
 #include <memory>
 #include <string>
 #include <vector>

src/sksl/codegen/SkSLWGSLCodeGenerator.h

@@ -8,16 +8,16 @@
 #ifndef SKSL_WGSLCODEGENERATOR
 #define SKSL_WGSLCODEGENERATOR
 
-#include <stdint.h>
-#include <string_view>
-#include <type_traits>
-#include <utility>
-
 #include "include/private/SkSLDefines.h"
 #include "include/private/SkTHash.h"
 #include "include/sksl/SkSLOperator.h"
 #include "src/sksl/codegen/SkSLCodeGenerator.h"
 
+#include <cstdint>
+#include <string_view>
+#include <type_traits>
+#include <utility>
+
 namespace sknonstd {
 template <typename T> struct is_bitmask_enum;
 }  // namespace sknonstd

src/sksl/dsl/DSLCore.cpp

@@ -49,6 +49,7 @@
 #include "src/sksl/ir/SkSLVariable.h"
 #include "src/sksl/transform/SkSLTransform.h"
 
+#include <cstddef>
 #include <type_traits>
 #include <vector>
 

src/sksl/dsl/DSLFunction.cpp

@@ -25,6 +25,7 @@
 #include "src/sksl/ir/SkSLFunctionPrototype.h"
 #include "src/sksl/ir/SkSLVariable.h"
 
+#include <cstddef>
 #include <memory>
 #include <string>
 #include <vector>

src/sksl/ir/SkSLChildCall.cpp

@@ -14,6 +14,8 @@
 #include "src/sksl/ir/SkSLType.h"
 #include "src/sksl/ir/SkSLVariable.h"
 
+#include <cstddef>
+
 namespace SkSL {
 
 bool ChildCall::hasProperty(Property property) const {

src/sksl/ir/SkSLConstructorCompoundCast.cpp

@@ -17,6 +17,7 @@
 #include "src/sksl/ir/SkSLLiteral.h"
 #include "src/sksl/ir/SkSLType.h"
 
+#include <cstddef>
 #include <optional>
 
 namespace SkSL {

src/sksl/ir/SkSLFieldAccess.cpp

@@ -22,6 +22,8 @@
 #include "src/sksl/ir/SkSLSymbolTable.h"
 #include "src/sksl/ir/SkSLUnresolvedFunction.h"
 
+#include <cstddef>
+
 namespace SkSL {
 
 std::unique_ptr<Expression> FieldAccess::Convert(const Context& context,

src/sksl/ir/SkSLFunctionCall.cpp

@@ -38,6 +38,8 @@
 #include <algorithm>
 #include <array>
 #include <cmath>
+#include <cstddef>
+#include <cstdint>
 #include <optional>
 #include <string_view>
 

src/sksl/ir/SkSLFunctionDeclaration.cpp

@@ -28,6 +28,7 @@
 #include "src/sksl/ir/SkSLUnresolvedFunction.h"
 #include "src/sksl/ir/SkSLVariable.h"
 
+#include <cstddef>
 #include <initializer_list>
 #include <utility>
 

src/sksl/ir/SkSLFunctionDefinition.cpp

@@ -35,6 +35,7 @@
 #include "src/sksl/transform/SkSLProgramWriter.h"
 
 #include <algorithm>
+#include <cstddef>
 #include <forward_list>
 #include <string_view>
 #include <unordered_map>

src/sksl/ir/SkSLIndexExpression.cpp

@@ -22,6 +22,7 @@
 #include "src/sksl/ir/SkSLType.h"
 #include "src/sksl/ir/SkSLTypeReference.h"
 
+#include <cstdint>
 #include <optional>
 
 namespace SkSL {

src/sksl/ir/SkSLSwizzle.cpp

@@ -20,6 +20,8 @@
 #include "src/sksl/ir/SkSLLiteral.h"
 
 #include <algorithm>
+#include <cstddef>
+#include <cstdint>
 #include <optional>
 
 namespace SkSL {

src/sksl/ir/SkSLSymbolTable.h

@@ -13,6 +13,8 @@
 #include "include/private/SkSLSymbol.h"
 #include "include/private/SkTHash.h"
 
+#include <cstddef>
+#include <cstdint>
 #include <forward_list>
 #include <memory>
 #include <string>

src/sksl/ir/SkSLType.h

@@ -15,6 +15,8 @@
 #include "include/sksl/SkSLPosition.h"
 #include "src/sksl/spirv.h"
 
+#include <cstddef>
+#include <cstdint>
 #include <memory>
 #include <string>
 #include <string_view>

src/sksl/ir/SkSLVariable.h

@@ -15,6 +15,7 @@
 #include "include/sksl/SkSLPosition.h"
 #include "src/sksl/ir/SkSLType.h"
 
+#include <cstdint>
 #include <memory>
 #include <string>
 #include <string_view>

src/sksl/ir/SkSLVariableReference.h

@@ -12,6 +12,7 @@
 #include "include/sksl/SkSLPosition.h"
 #include "src/sksl/ir/SkSLExpression.h"
 
+#include <cstdint>
 #include <memory>
 #include <string>
 

src/sksl/tracing/SkVMDebugTrace.h

@@ -14,8 +14,8 @@
 #include "src/core/SkVM.h"
 #include "src/sksl/ir/SkSLType.h"
 
+#include <cstdint>
 #include <memory>
-#include <stdint.h>
 #include <string>
 #include <vector>
 

src/utils/SkAnimCodecPlayer.cpp

@@ -24,6 +24,7 @@
 #include "src/codec/SkCodecImageGenerator.h"
 
 #include <algorithm>
+#include <cstddef>
 #include <memory>
 #include <utility>
 #include <vector>

src/utils/SkBase64.cpp

@@ -8,6 +8,8 @@
 
 #include "include/utils/SkBase64.h"
 
+#include <cstdint>
+
 #define DecodePad -2
 #define EncodePad 64
 

src/utils/SkCanvasStateUtils.cpp

@@ -22,6 +22,8 @@
 #include "src/core/SkWriter32.h"
 #include "src/utils/SkCanvasStack.h"
 
+#include <cstddef>
+#include <cstdint>
 #include <utility>
 
 /*

src/utils/SkCharToGlyphCache.h

@@ -12,6 +12,8 @@
 #include "include/private/SkTDArray.h"
 #include "include/private/SkTo.h"
 
+#include <cstdint>
+
 class SkCharToGlyphCache {
 public:
     SkCharToGlyphCache();

src/utils/SkCustomTypeface.cpp

@@ -33,8 +33,10 @@
 #include "src/core/SkPathPriv.h"
 #include "src/core/SkScalerContext.h"
 
-#include <string.h>
+#include <cstddef>
+#include <cstdint>
 #include <memory>
+#include <string>
 #include <utility>
 #include <vector>
 

src/utils/SkDashPath.cpp

@@ -22,6 +22,7 @@
 
 #include <algorithm>
 #include <cmath>
+#include <cstdint>
 #include <iterator>
 #include <utility>
 

src/utils/SkMultiPictureDocument.cpp

@@ -21,10 +21,12 @@
 #include "include/utils/SkNWayCanvas.h"
 #include "src/utils/SkMultiPictureDocumentPriv.h"
 
-#include <limits.h>
-#include <string.h>
 #include <algorithm>
+#include <climits>
+#include <cstddef>
+#include <cstdint>
 #include <functional>
+#include <string>
 
 /*
   File format:

src/utils/SkParse.cpp

@@ -7,9 +7,8 @@
 
 #include "include/utils/SkParse.h"
 
-#include <iterator>  // for std::size
-#include <stdlib.h>
-#include <string.h>
+#include <cstdlib>
+#include <string>
 
 static inline bool is_between(int c, int min, int max)
 {

src/utils/SkParseColor.cpp

@@ -4,15 +4,16 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
-
 #include "include/utils/SkParse.h"
 
 #include "include/core/SkColor.h"
 #include "include/core/SkTypes.h"
 
-#include <string.h>
 #include <algorithm>
+#include <cstddef>
+#include <cstdint>
 #include <iterator>
+#include <string>
 
 static constexpr const char* gColorNames[] = {
     "aliceblue",

src/utils/SkParsePath.cpp

@@ -16,7 +16,7 @@
 #include "include/utils/SkParsePath.h"
 #include "src/core/SkGeometry.h"
 
-#include <stdio.h>
+#include <cstdio>
 
 static inline bool is_between(int c, int min, int max) {
     return (unsigned)(c - min) <= (unsigned)(max - min);

src/utils/SkPatchUtils.cpp

@@ -27,8 +27,9 @@
 #include "src/core/SkConvertPixels.h"
 #include "src/core/SkGeometry.h"
 
-#include <string.h>
 #include <algorithm>
+#include <cstdint>
+#include <string>
 
 namespace {
     enum CubicCtrlPts {

src/utils/SkPolyUtils.h

@@ -11,7 +11,7 @@
 #include "include/core/SkPoint.h"
 #include "include/core/SkScalar.h"
 
-#include <stdint.h>
+#include <cstdint>
 
 struct SkRect;
 template <typename T> class SkTDArray;

src/utils/SkShaderUtils.cpp

@@ -12,6 +12,8 @@
 #include "include/private/SkTArray.h"
 #include "src/sksl/SkSLProgramSettings.h"
 
+#include <cstddef>
+
 namespace SkShaderUtils {
 
 class GLSLPrettyPrint {

src/utils/SkShadowTessellator.cpp

@@ -27,6 +27,8 @@
 #include "src/utils/SkPolyUtils.h"
 
 #include <algorithm>
+#include <cstdint>
+
 
 #if SK_SUPPORT_GPU
 #include "src/gpu/ganesh/geometry/GrPathUtils.h"

src/utils/SkShadowUtils.cpp

@@ -51,12 +51,12 @@ class GrColorInfo;
 class GrRecordingContext;
 #endif
 
-#include <string.h>
 #include <algorithm>
-#include <cstdint>
+#include <cstddef>
 #include <functional>
 #include <memory>
 #include <new>
+#include <string>
 #include <utility>
 
 class SkArenaAlloc;

src/utils/SkUTF.h

@@ -5,6 +5,9 @@
 
 #include "include/core/SkTypes.h"
 
+#include <cstddef>
+#include <cstdint>
+
 typedef int32_t SkUnichar;
 
 namespace SkUTF {

src/utils/SkVMVisualizer.cpp

@@ -15,8 +15,8 @@
 #endif
 
 #include <algorithm>
+#include <cstdarg>
 #include <sstream>
-#include <stdarg.h>
 #include <string>
 #include <utility>
 

src/utils/SkVMVisualizer.h

@@ -14,6 +14,7 @@
 #include "src/core/SkVM.h"
 
 #include <cstddef>
+#include <cstdint>
 #include <type_traits>
 #include <vector>
 

toolchain/linux_trampolines/IWYU_mapping.imp

@@ -12,16 +12,34 @@
   { include: ["<__algorithm/stable_sort.h>", "private", "<algorithm>", "public"] },
   { include: ["<__algorithm/upper_bound.h>", "private", "<algorithm>", "public"] },
 
+  { symbol: ["INT32_MAX", "public", "<climits>", "public"]},
+
   { symbol: ["abs", "public", "<cmath>", "public"]},
 
-  { symbol: ["uint8_t", "public", "<cstdint>", "public"]},
+  # The first of these is the preferred include, but the others are acceptable.
+  { symbol: ["size_t", "public", "<cstddef>", "public"]},
+  { symbol: ["size_t", "public", "<cstdio>", "public"]},
+  { symbol: ["size_t", "public", "<cstdlib>", "public"]},
+  { symbol: ["size_t", "public", "<cstring>", "public"]},
+  { symbol: ["size_t", "public", "<ctime>", "public"]},
+  { symbol: ["size_t", "public", "<cuchar>", "public"]},
+  { symbol: ["size_t", "public", "<cwchar>", "public"]},
+
   { symbol: ["int8_t", "public", "<cstdint>", "public"]},
+  { symbol: ["int16_t", "public", "<cstdint>", "public"]},
+  { symbol: ["int32_t", "public", "<cstdint>", "public"]},
+  { symbol: ["int64_t", "public", "<cstdint>", "public"]},
+  { symbol: ["uint8_t", "public", "<cstdint>", "public"]},
+  { symbol: ["uint16_t", "public", "<cstdint>", "public"]},
+  { symbol: ["uint32_t", "public", "<cstdint>", "public"]},
+  { symbol: ["uint64_t", "public", "<cstdint>", "public"]},
 
   { include: ["<__functional/function.h>", "private", "<functional>", "public"] },
 
   { include: ["<__iterator/access.h>", "private", "<iterator>", "public"] },
   { include: ["<__iterator/distance.h>", "private", "<iterator>", "public"] },
 
+  # The first of these is the preferred include, but the others are acceptable.
   { include: ["<__iterator/size.h>", "private", "<array>", "public"] },
   { include: ["<__iterator/size.h>", "private", "<deque>", "public"] },
   { include: ["<__iterator/size.h>", "private", "<forward_list>", "public"] },
@@ -43,9 +61,17 @@
 
   { include: ["<__tree>", "private", "<set>", "public"] },
 
+  { symbol: ["std::istringstream", "public", "<sstream>", "public"] },
+  { symbol: ["std::ostringstream", "public", "<sstream>", "public"] },
+  { symbol: ["std::stringstream", "public", "<sstream>", "public"] },
+  { symbol: ["std::stringbuf", "public", "<sstream>", "public"] },
+  { symbol: ["std::basic_istringstream", "public", "<sstream>", "public"] },
+  { symbol: ["std::basic_ostringstream", "public", "<sstream>", "public"] },
+  { symbol: ["std::basic_stringstream", "public", "<sstream>", "public"] },
+  { symbol: ["std::basic_stringbuf", "public", "<sstream>", "public"] },
+
   { symbol: ["va_list", "public", "<stdarg.h>", "public"] },
 
-  { include: ["<string.h>", "public", "<string>", "public"] },
   { symbol: ["std::string", "public", "<string>", "public"] },
 
   { include: ["<__hash_table>", "private", "<unordered_map>", "public"] },
@@ -56,4 +82,61 @@
   { include: ["<__utility/pair.h>", "private", "<utility>", "public"] },
 
   { symbol: ["std::__bit_reference", "public", "<vector>", "public"] },
+
+  # Without these, IWYU won't accept the C++ wrappers and throws
+  # a mysterious "cyclical import" error.
+  # https://github.com/include-what-you-use/include-what-you-use/blob/4c0f39615982c57a9cb313c971c6f45fca1cc1fe/iwyu_include_picker.cc#L573
+  { include: ["<assert.h>", "public", "<cassert>", "public"] },
+  { include: ["<complex.h>", "public", "<ccomplex>", "public"] },
+  { include: ["<ctype.h>", "public", "<cctype>", "public"] },
+  { include: ["<errno.h>", "public", "<cerrno>", "public"] },
+  { include: ["<fenv.h>", "public", "<cfenv>", "public"] },
+  { include: ["<float.h>", "public", "<cfloat>", "public"] },
+  { include: ["<inttypes.h>", "public", "<cinttypes>", "public"] },
+  { include: ["<iso646.h>", "public", "<ciso646>", "public"] },
+  { include: ["<limits.h>", "public", "<climits>", "public"] },
+  { include: ["<locale.h>", "public", "<clocale>", "public"] },
+  { include: ["<math.h>", "public", "<cmath>", "public"] },
+  { include: ["<setjmp.h>", "public", "<csetjmp>", "public"] },
+  { include: ["<signal.h>", "public", "<csignal>", "public"] },
+  { include: ["<stdalign.h>", "public", "<cstdalign>", "public"] },
+  { include: ["<stdarg.h>", "public", "<cstdarg>", "public"] },
+  { include: ["<stdbool.h>", "public", "<cstdbool>", "public"] },
+  { include: ["<stddef.h>", "public", "<cstddef>", "public"] },
+  { include: ["<stdint.h>", "public", "<cstdint>", "public"] },
+  { include: ["<stdio.h>", "public", "<cstdio>", "public"] },
+  { include: ["<stdlib.h>", "public", "<cstdlib>", "public"] },
+  { include: ["<string.h>", "public", "<string>", "public"] },
+  { include: ["<string.h>", "public", "<cstring>", "public"] },
+  { include: ["<tgmath.h>", "public", "<ctgmath>", "public"] },
+  { include: ["<time.h>", "public", "<ctime>", "public"] },
+  { include: ["<uchar.h>", "public", "<cuchar>", "public"] },
+  { include: ["<wchar.h>", "public", "<cwchar>", "public"] },
+  { include: ["<wctype.h>", "public", "<cwctype>", "public"] },
+
+  # From https://github.com/include-what-you-use/include-what-you-use/blob/4c0f39615982c57a9cb313c971c6f45fca1cc1fe/iwyu_include_picker.cc#L327
+  { symbol: ["std::allocator", "private", "<memory>", "public"] },
+  { symbol: ["std::allocator", "private", "<string>", "public"] },
+  { symbol: ["std::allocator", "private", "<vector>", "public"] },
+  { symbol: ["std::allocator", "private", "<map>", "public"] },
+  { symbol: ["std::allocator", "private", "<set>", "public"] },
+  { symbol: ["std::char_traits", "private", "<string>", "public"] },
+  { symbol: ["std::char_traits", "private", "<ostream>", "public"] },
+  { symbol: ["std::char_traits", "private", "<istream>", "public"] },
+
+  # We are pretty forgiving with iostream headers. If we specify
+  # any of them, that is generally sufficient.
+  # https://github.com/include-what-you-use/include-what-you-use/blob/4c0f39615982c57a9cb313c971c6f45fca1cc1fe/iwyu_include_picker.cc#L995
+  {include: ["<ios>", "public", "<istream>", "public"] },
+  {include: ["<ios>", "public", "<ostream>", "public"] },
+  {include: ["<iosfwd>", "public", "<ios>", "public"] },
+  {include: ["<iosfwd>", "public", "<streambuf>", "public"] },
+  {include: ["<istream>", "public", "<fstream>", "public"] },
+  {include: ["<istream>", "public", "<iostream>", "public"] },
+  {include: ["<istream>", "public", "<sstream>", "public"] },
+  {include: ["<ostream>", "public", "<fstream>", "public"] },
+  {include: ["<ostream>", "public", "<iostream>", "public"] },
+  {include: ["<ostream>", "public", "<istream>", "public"] },
+  {include: ["<ostream>", "public", "<sstream>", "public"] },
+  {include: ["<streambuf>", "public", "<ios>", "public"] },
 ]

toolchain/linux_trampolines/clang_trampoline_linux.sh

@@ -60,6 +60,7 @@ else
   # not consistent with detecting that.
   external/clang_linux_amd64/usr/bin/include-what-you-use \
       -Xiwyu --keep="include/core/SkTypes.h" \
+      -Xiwyu --no_default_mappings \
       -Xiwyu --mapping_file=$MAPPING_FILE $@ 2>/dev/null
   # IWYU returns 2 if everything looks good. It returns some other non-zero exit code otherwise.
   if [ $? -eq 2 ]; then
@@ -70,6 +71,7 @@ else
     # analysis. If we aren't sure why IWYU wants to include something, try changing verbose to 3.
     external/clang_linux_amd64/usr/bin/include-what-you-use \
         -Xiwyu --keep="include/core/SkTypes.h" \
+        -Xiwyu --no_default_mappings \
         -Xiwyu --mapping_file=$MAPPING_FILE -Xiwyu --no_comments \
         -Xiwyu --quoted_includes_first -Xiwyu --verbose=3 $@
     exit 1 # fail the build