Prepare for -Wimplicit-fallthrough in ANGLE.

src/common/angle_fallthrough.h

+//
+// Copyright 2018 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// aligned_memory: Defines ANGLE_FALLTHROUGH. Do not include in public headers.
+//
+
+#ifndef COMMON_ANGLE_FALLTHROUGH_H_
+#define COMMON_ANGLE_FALLTHROUGH_H_
+
+// When clang suggests inserting [[clang::fallthrough]], it first checks if
+// it knows of a macro expanding to it, and if so suggests inserting the
+// macro.  This means that this macro must be used only in code internal
+// to ANGLE, so that ANGLE's user code doesn't end up getting suggestions
+// for ANGLE_FALLTHROUGH instead of the user-specific fallthrough macro.
+// So do not include this header in any of ANGLE's public headers.
+#if defined(__clang__)
+#define ANGLE_FALLTHROUGH [[clang::fallthrough]]
+#else
+#define ANGLE_FALLTHROUGH
+#endif
+
+#endif  // COMMON_ANGLE_FALLTHROUGH_H_

src/compiler/preprocessor/Tokenizer.cpp

@@ -911,6 +911,10 @@ IF YOU MODIFY THIS FILE YOU ALSO NEED TO RUN generate_parser.sh.
 #elif defined(_MSC_VER)
 #pragma warning(disable: 4244)
 #endif
+#if defined(__clang__)
+// Flex uses `/*FALLTHROUGH*/` instead of dedicated statements.
+#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#endif
 
 // Workaround for flex using the register keyword, deprecated in C++11.
 #ifdef __cplusplus

src/compiler/preprocessor/Tokenizer.l

@@ -38,6 +38,10 @@ IF YOU MODIFY THIS FILE YOU ALSO NEED TO RUN generate_parser.sh.
 #elif defined(_MSC_VER)
 #pragma warning(disable: 4244)
 #endif
+#if defined(__clang__)
+// Flex uses `/*FALLTHROUGH*/` instead of dedicated statements.
+#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#endif
 
 // Workaround for flex using the register keyword, deprecated in C++11.
 #ifdef __cplusplus

src/compiler/translator/ASTMetadataHLSL.cpp

@@ -105,6 +105,7 @@ class PullGradient : public TIntermTraverser
                 case EOpDFdy:
                 case EOpFwidth:
                     onGradient();
+                    break;
                 default:
                     break;
             }

src/compiler/translator/EmulatePrecision.cpp

@@ -6,6 +6,7 @@
 
 #include "compiler/translator/EmulatePrecision.h"
 
+#include "common/angle_fallthrough.h"
 #include "compiler/translator/FunctionLookup.h"
 
 #include <memory>
@@ -639,6 +640,7 @@ bool EmulatePrecision::visitAggregate(Visit visit, TIntermAggregate *node)
             {
                 break;
             }
+            ANGLE_FALLTHROUGH;
         default:
             TIntermNode *parent = getParentNode();
             if (canRoundFloat(node->getType()) && ParentUsesResult(parent, node) &&

src/compiler/translator/IntermNode.cpp

@@ -1588,6 +1588,7 @@ bool TIntermBinary::hasConstantValue() const
             {
                 return true;
             }
+            break;
         }
         default:
             break;

src/compiler/translator/ParseContext.cpp

@@ -4918,6 +4918,7 @@ TIntermTyped *TParseContext::createUnaryMath(TOperator op,
                 unaryOpError(loc, GetOperatorString(op), child->getCompleteString());
                 return nullptr;
             }
+            break;
         // Operators for built-ins are already type checked against their prototype.
         default:
             break;

src/compiler/translator/glslang.l

@@ -26,9 +26,9 @@ WHICH GENERATES THE GLSL ES LEXER (glslang_lex.cpp).
 
 // Ignore errors in auto-generated code.
 #if defined(__GNUC__)
+#pragma GCC diagnostic ignored "-Wswitch-enum"
 #pragma GCC diagnostic ignored "-Wunused-function"
 #pragma GCC diagnostic ignored "-Wunused-variable"
-#pragma GCC diagnostic ignored "-Wswitch-enum"
 #elif defined(_MSC_VER)
 #pragma warning(disable: 4005)
 #pragma warning(disable: 4065)
@@ -38,6 +38,9 @@ WHICH GENERATES THE GLSL ES LEXER (glslang_lex.cpp).
 #pragma warning(disable: 4701)
 #pragma warning(disable: 4702)
 #endif
+#if defined(__clang__)
+#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#endif
 }
 
 %{

src/compiler/translator/glslang_lex.cpp

@@ -11,9 +11,9 @@
 
 // Ignore errors in auto-generated code.
 #if defined(__GNUC__)
+#pragma GCC diagnostic ignored "-Wswitch-enum"
 #pragma GCC diagnostic ignored "-Wunused-function"
 #pragma GCC diagnostic ignored "-Wunused-variable"
-#pragma GCC diagnostic ignored "-Wswitch-enum"
 #elif defined(_MSC_VER)
 #pragma warning(disable: 4005)
 #pragma warning(disable: 4065)
@@ -23,6 +23,9 @@
 #pragma warning(disable: 4701)
 #pragma warning(disable: 4702)
 #endif
+#if defined(__clang__)
+#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#endif
 
 
 

src/libANGLE/State.cpp

@@ -1766,9 +1766,10 @@ void State::getFloatv(GLenum pname, GLfloat *params)
         break;
       case GL_SAMPLE_ALPHA_TO_ONE_EXT:
         *params = static_cast<GLfloat>(mSampleAlphaToOne);
+        break;
       case GL_COVERAGE_MODULATION_CHROMIUM:
-          params[0] = static_cast<GLfloat>(mCoverageModulation);
-          break;
+        params[0] = static_cast<GLfloat>(mCoverageModulation);
+        break;
       default:
         UNREACHABLE();
         break;
@@ -2051,6 +2052,7 @@ void State::getIntegerv(const Context *context, GLenum pname, GLint *params)
           break;
       case GL_SAMPLE_ALPHA_TO_ONE_EXT:
           *params = static_cast<GLint>(mSampleAlphaToOne);
+          break;
       case GL_COVERAGE_MODULATION_CHROMIUM:
           *params = static_cast<GLint>(mCoverageModulation);
           break;

src/libANGLE/renderer/d3d/d3d11/StateManager11.cpp

@@ -1032,6 +1032,7 @@ void StateManager11::syncState(const gl::Context *context, const gl::State::Dirt
                 {
                     invalidateCurrentValueAttrib(attribIndex);
                 }
+                break;
             }
             default:
                 break;

src/libANGLE/renderer/d3d/d3d9/StateManager9.cpp

@@ -250,6 +250,7 @@ void StateManager9::syncState(const gl::State &state, const gl::State::DirtyBits
                 {
                     mDirtyBits.set(DIRTY_BIT_DEPTH_BIAS);
                 }
+                break;
             }
             case gl::State::DIRTY_BIT_DEPTH_MASK:
                 if (state.getDepthStencilState().depthMask != mCurDepthStencilState.depthMask)

src/libANGLE/renderer/gen_load_functions_table.py

@@ -80,12 +80,11 @@ LoadFunctionMap GetLoadFunctionsMap(GLenum {internal_format}, Format::ID {angle_
     {{
 {switch_data}
         default:
-        {{
-            static LoadFunctionMap emptyLoadFunctionsMap;
-            return emptyLoadFunctionsMap;
-        }}
+            break;
     }}
     // clang-format on
+    static LoadFunctionMap emptyLoadFunctionsMap;
+    return emptyLoadFunctionsMap;
 
 }}  // GetLoadFunctionsMap
 
@@ -163,15 +162,21 @@ def parse_json(json_data):
         if do_switch:
             table_data += s + 'default:\n'
 
+        has_break_in_switch = False
         if angle_format_unknown in angle_to_type_map:
             table_data += s + '    return ' + unknown_func_name(internal_format) + ';\n'
             load_functions_data += get_unknown_load_func(angle_to_type_map, internal_format)
         else:
+            has_break_in_switch = True
             table_data += s + '    break;\n'
 
         if do_switch:
             s = s[4:]
             table_data += s + '}\n'
+            if has_break_in_switch:
+                # If the inner switch contains a break statement, add a break
+                # statement after the switch as well.
+                table_data += s + 'break;\n'
             s = s[4:]
             table_data += s + '}\n'
 

src/libANGLE/validationEGL.cpp

@@ -445,6 +445,7 @@ Error ValidateGetPlatformDisplayCommon(EGLenum platform,
                                   "platform type of EGL_PLATFORM_ANGLE_TYPE_D3D9_ANGLE or "
                                   "EGL_PLATFORM_ANGLE_TYPE_D3D9_ANGLE.";
                     }
+                    break;
                 default:
                     break;
             }
@@ -2473,6 +2474,7 @@ Error ValidateSurfaceAttrib(const Display *display,
                 default:
                     return EglBadAttribute() << "Invalid multisample resolve type.";
             }
+            break;
 
         case EGL_SWAP_BEHAVIOR:
             switch (value)
@@ -2491,6 +2493,7 @@ Error ValidateSurfaceAttrib(const Display *display,
                 default:
                     return EglBadAttribute() << "Invalid swap behaviour.";
             }
+            break;
 
         default:
             return EglBadAttribute() << "Invalid surface attribute.";

src/libANGLE/validationES2.cpp

@@ -3328,6 +3328,7 @@ bool ValidatePathParameterfCHROMIUM(Context *context, GLuint path, GLenum pname,
                     context->handleError(InvalidEnum() << "Invalid join style.");
                     return false;
             }
+            break;
         case GL_PATH_MITER_LIMIT_CHROMIUM:
             if (value < 0.0f)
             {