1 files changed, 531 insertions, 0 deletions
diff --git a/gfx/angle/checkout/src/compiler/preprocessor/MacroExpander.cpp b/gfx/angle/checkout/src/compiler/preprocessor/MacroExpander.cpp
new file mode 100644
index 0000000000..759617b5a1
--- /dev/null
+++ b/gfx/angle/checkout/src/compiler/preprocessor/MacroExpander.cpp
@@ -0,0 +1,531 @@
+//
+// Copyright 2011 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.
+//
+
+#include "compiler/preprocessor/MacroExpander.h"
+
+#include <GLSLANG/ShaderLang.h>
+#include <algorithm>
+
+#include "common/debug.h"
+#include "compiler/preprocessor/DiagnosticsBase.h"
+#include "compiler/preprocessor/Token.h"
+
+namespace angle
+{
+
+namespace pp
+{
+
+namespace
+{
+
+const size_t kMaxContextTokens = 10000;
+
+class TokenLexer : public Lexer
+{
+  public:
+    typedef std::vector<Token> TokenVector;
+
+    TokenLexer(TokenVector *tokens)
+    {
+        tokens->swap(mTokens);
+        mIter = mTokens.begin();
+    }
+
+    void lex(Token *token) override
+    {
+        if (mIter == mTokens.end())
+        {
+            token->reset();
+            token->type = Token::LAST;
+        }
+        else
+        {
+            *token = *mIter++;
+        }
+    }
+
+  private:
+    TokenVector mTokens;
+    TokenVector::const_iterator mIter;
+};
+
+}  // anonymous namespace
+
+class [[nodiscard]] MacroExpander::ScopedMacroReenabler final : angle::NonCopyable
+{
+  public:
+    ScopedMacroReenabler(MacroExpander *expander);
+    ~ScopedMacroReenabler();
+
+  private:
+    MacroExpander *mExpander;
+};
+
+MacroExpander::ScopedMacroReenabler::ScopedMacroReenabler(MacroExpander *expander)
+    : mExpander(expander)
+{
+    mExpander->mDeferReenablingMacros = true;
+}
+
+MacroExpander::ScopedMacroReenabler::~ScopedMacroReenabler()
+{
+    mExpander->mDeferReenablingMacros = false;
+    for (const std::shared_ptr<Macro> &macro : mExpander->mMacrosToReenable)
+    {
+        // Copying the string here by using substr is a check for use-after-free. It detects
+        // use-after-free more reliably than just toggling the disabled flag.
+        ASSERT(macro->name.substr() != "");
+        macro->disabled = false;
+    }
+    mExpander->mMacrosToReenable.clear();
+}
+
+MacroExpander::MacroExpander(Lexer *lexer,
+                             MacroSet *macroSet,
+                             Diagnostics *diagnostics,
+                             const PreprocessorSettings &settings,
+                             bool parseDefined)
+    : mLexer(lexer),
+      mMacroSet(macroSet),
+      mDiagnostics(diagnostics),
+      mParseDefined(parseDefined),
+      mTotalTokensInContexts(0),
+      mSettings(settings),
+      mDeferReenablingMacros(false)
+{}
+
+MacroExpander::~MacroExpander()
+{
+    ASSERT(mMacrosToReenable.empty());
+    for (MacroContext *context : mContextStack)
+    {
+        delete context;
+    }
+}
+
+void MacroExpander::lex(Token *token)
+{
+    while (true)
+    {
+        getToken(token);
+
+        if (token->type != Token::IDENTIFIER)
+            break;
+
+        // Defined operator is parsed here since it may be generated by macro expansion.
+        // Defined operator produced by macro expansion has undefined behavior according to C++
+        // spec, which the GLSL spec references (see C++14 draft spec section 16.1.4), but this
+        // behavior is needed for passing dEQP tests, which enforce stricter compatibility between
+        // implementations.
+        if (mParseDefined && token->text == kDefined)
+        {
+            // Defined inside a macro is forbidden in WebGL.
+            if (!mContextStack.empty() && sh::IsWebGLBasedSpec(mSettings.shaderSpec))
+                break;
+
+            bool paren = false;
+            getToken(token);
+            if (token->type == '(')
+            {
+                paren = true;
+                getToken(token);
+            }
+            if (token->type != Token::IDENTIFIER)
+            {
+                mDiagnostics->report(Diagnostics::PP_UNEXPECTED_TOKEN, token->location,
+                                     token->text);
+                break;
+            }
+            auto iter              = mMacroSet->find(token->text);
+            std::string expression = iter != mMacroSet->end() ? "1" : "0";
+
+            if (paren)
+            {
+                getToken(token);
+                if (token->type != ')')
+                {
+                    mDiagnostics->report(Diagnostics::PP_UNEXPECTED_TOKEN, token->location,
+                                         token->text);
+                    break;
+                }
+            }
+
+            // We have a valid defined operator.
+            // Convert the current token into a CONST_INT token.
+            token->type = Token::CONST_INT;
+            token->text = expression;
+            break;
+        }
+
+        if (token->expansionDisabled())
+            break;
+
+        MacroSet::const_iterator iter = mMacroSet->find(token->text);
+        if (iter == mMacroSet->end())
+            break;
+
+        std::shared_ptr<Macro> macro = iter->second;
+        if (macro->disabled)
+        {
+            // If a particular token is not expanded, it is never expanded.
+            token->setExpansionDisabled(true);
+            break;
+        }
+
+        // Bump the expansion count before peeking if the next token is a '('
+        // otherwise there could be a #undef of the macro before the next token.
+        macro->expansionCount++;
+        if ((macro->type == Macro::kTypeFunc) && !isNextTokenLeftParen())
+        {
+            // If the token immediately after the macro name is not a '(',
+            // this macro should not be expanded.
+            macro->expansionCount--;
+            break;
+        }
+
+        pushMacro(macro, *token);
+    }
+}
+
+void MacroExpander::getToken(Token *token)
+{
+    if (mReserveToken.get())
+    {
+        *token = *mReserveToken;
+        mReserveToken.reset();
+        return;
+    }
+
+    // First pop all empty macro contexts.
+    while (!mContextStack.empty() && mContextStack.back()->empty())
+    {
+        popMacro();
+    }
+
+    if (!mContextStack.empty())
+    {
+        *token = mContextStack.back()->get();
+    }
+    else
+    {
+        ASSERT(mTotalTokensInContexts == 0);
+        mLexer->lex(token);
+    }
+}
+
+void MacroExpander::ungetToken(const Token &token)
+{
+    if (!mContextStack.empty())
+    {
+        MacroContext *context = mContextStack.back();
+        context->unget();
+        ASSERT(context->replacements[context->index] == token);
+    }
+    else
+    {
+        ASSERT(!mReserveToken.get());
+        mReserveToken.reset(new Token(token));
+    }
+}
+
+bool MacroExpander::isNextTokenLeftParen()
+{
+    Token token;
+    getToken(&token);
+
+    bool lparen = token.type == '(';
+    ungetToken(token);
+
+    return lparen;
+}
+
+bool MacroExpander::pushMacro(std::shared_ptr<Macro> macro, const Token &identifier)
+{
+    ASSERT(!macro->disabled);
+    ASSERT(!identifier.expansionDisabled());
+    ASSERT(identifier.type == Token::IDENTIFIER);
+    ASSERT(identifier.text == macro->name);
+
+    std::vector<Token> replacements;
+    if (!expandMacro(*macro, identifier, &replacements))
+        return false;
+
+    // Macro is disabled for expansion until it is popped off the stack.
+    macro->disabled = true;
+
+    MacroContext *context = new MacroContext;
+    context->macro        = macro;
+    context->replacements.swap(replacements);
+    mContextStack.push_back(context);
+    mTotalTokensInContexts += context->replacements.size();
+    return true;
+}
+
+void MacroExpander::popMacro()
+{
+    ASSERT(!mContextStack.empty());
+
+    MacroContext *context = mContextStack.back();
+    mContextStack.pop_back();
+
+    ASSERT(context->empty());
+    ASSERT(context->macro->disabled);
+    ASSERT(context->macro->expansionCount > 0);
+    if (mDeferReenablingMacros)
+    {
+        mMacrosToReenable.push_back(context->macro);
+    }
+    else
+    {
+        context->macro->disabled = false;
+    }
+    context->macro->expansionCount--;
+    mTotalTokensInContexts -= context->replacements.size();
+    delete context;
+}
+
+bool MacroExpander::expandMacro(const Macro &macro,
+                                const Token &identifier,
+                                std::vector<Token> *replacements)
+{
+    replacements->clear();
+
+    // In the case of an object-like macro, the replacement list gets its location
+    // from the identifier, but in the case of a function-like macro, the replacement
+    // list gets its location from the closing parenthesis of the macro invocation.
+    // This is tested by dEQP-GLES3.functional.shaders.preprocessor.predefined_macros.*
+    SourceLocation replacementLocation = identifier.location;
+    if (macro.type == Macro::kTypeObj)
+    {
+        replacements->assign(macro.replacements.begin(), macro.replacements.end());
+
+        if (macro.predefined)
+        {
+            const char kLine[] = "__LINE__";
+            const char kFile[] = "__FILE__";
+
+            ASSERT(replacements->size() == 1);
+            Token &repl = replacements->front();
+            if (macro.name == kLine)
+            {
+                repl.text = ToString(identifier.location.line);
+            }
+            else if (macro.name == kFile)
+            {
+                repl.text = ToString(identifier.location.file);
+            }
+        }
+    }
+    else
+    {
+        ASSERT(macro.type == Macro::kTypeFunc);
+        std::vector<MacroArg> args;
+        args.reserve(macro.parameters.size());
+        if (!collectMacroArgs(macro, identifier, &args, &replacementLocation))
+            return false;
+
+        replaceMacroParams(macro, args, replacements);
+    }
+
+    for (std::size_t i = 0; i < replacements->size(); ++i)
+    {
+        Token &repl = replacements->at(i);
+        if (i == 0)
+        {
+            // The first token in the replacement list inherits the padding
+            // properties of the identifier token.
+            repl.setAtStartOfLine(identifier.atStartOfLine());
+            repl.setHasLeadingSpace(identifier.hasLeadingSpace());
+        }
+        repl.location = replacementLocation;
+    }
+    return true;
+}
+
+bool MacroExpander::collectMacroArgs(const Macro &macro,
+                                     const Token &identifier,
+                                     std::vector<MacroArg> *args,
+                                     SourceLocation *closingParenthesisLocation)
+{
+    Token token;
+    getToken(&token);
+    ASSERT(token.type == '(');
+
+    args->push_back(MacroArg());
+
+    // Defer reenabling macros until args collection is finished to avoid the possibility of
+    // infinite recursion. Otherwise infinite recursion might happen when expanding the args after
+    // macros have been popped from the context stack when parsing the args.
+    ScopedMacroReenabler deferReenablingMacros(this);
+
+    int openParens = 1;
+    while (openParens != 0)
+    {
+        getToken(&token);
+
+        if (token.type == Token::LAST)
+        {
+            mDiagnostics->report(Diagnostics::PP_MACRO_UNTERMINATED_INVOCATION, identifier.location,
+                                 identifier.text);
+            // Do not lose EOF token.
+            ungetToken(token);
+            return false;
+        }
+
+        bool isArg = false;  // True if token is part of the current argument.
+        switch (token.type)
+        {
+            case '(':
+                ++openParens;
+                isArg = true;
+                break;
+            case ')':
+                --openParens;
+                isArg                       = openParens != 0;
+                *closingParenthesisLocation = token.location;
+                break;
+            case ',':
+                // The individual arguments are separated by comma tokens, but
+                // the comma tokens between matching inner parentheses do not
+                // seperate arguments.
+                if (openParens == 1)
+                    args->push_back(MacroArg());
+                isArg = openParens != 1;
+                break;
+            default:
+                isArg = true;
+                break;
+        }
+        if (isArg)
+        {
+            MacroArg &arg = args->back();
+            // Initial whitespace is not part of the argument.
+            if (arg.empty())
+                token.setHasLeadingSpace(false);
+            arg.push_back(token);
+        }
+    }
+
+    const Macro::Parameters &params = macro.parameters;
+    // If there is only one empty argument, it is equivalent to no argument.
+    if (params.empty() && (args->size() == 1) && args->front().empty())
+    {
+        args->clear();
+    }
+    // Validate the number of arguments.
+    if (args->size() != params.size())
+    {
+        Diagnostics::ID id = args->size() < macro.parameters.size()
+                                 ? Diagnostics::PP_MACRO_TOO_FEW_ARGS
+                                 : Diagnostics::PP_MACRO_TOO_MANY_ARGS;
+        mDiagnostics->report(id, identifier.location, identifier.text);
+        return false;
+    }
+
+    // Pre-expand each argument before substitution.
+    // This step expands each argument individually before they are
+    // inserted into the macro body.
+    size_t numTokens = 0;
+    for (auto &arg : *args)
+    {
+        TokenLexer lexer(&arg);
+        if (mSettings.maxMacroExpansionDepth < 1)
+        {
+            mDiagnostics->report(Diagnostics::PP_MACRO_INVOCATION_CHAIN_TOO_DEEP, token.location,
+                                 token.text);
+            return false;
+        }
+        PreprocessorSettings nestedSettings(mSettings.shaderSpec);
+        nestedSettings.maxMacroExpansionDepth = mSettings.maxMacroExpansionDepth - 1;
+        MacroExpander expander(&lexer, mMacroSet, mDiagnostics, nestedSettings, mParseDefined);
+
+        arg.clear();
+        expander.lex(&token);
+        while (token.type != Token::LAST)
+        {
+            arg.push_back(token);
+            expander.lex(&token);
+            numTokens++;
+            if (numTokens + mTotalTokensInContexts > kMaxContextTokens)
+            {
+                mDiagnostics->report(Diagnostics::PP_OUT_OF_MEMORY, token.location, token.text);
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+void MacroExpander::replaceMacroParams(const Macro &macro,
+                                       const std::vector<MacroArg> &args,
+                                       std::vector<Token> *replacements)
+{
+    for (std::size_t i = 0; i < macro.replacements.size(); ++i)
+    {
+        if (!replacements->empty() &&
+            replacements->size() + mTotalTokensInContexts > kMaxContextTokens)
+        {
+            const Token &token = replacements->back();
+            mDiagnostics->report(Diagnostics::PP_OUT_OF_MEMORY, token.location, token.text);
+            return;
+        }
+
+        const Token &repl = macro.replacements[i];
+        if (repl.type != Token::IDENTIFIER)
+        {
+            replacements->push_back(repl);
+            continue;
+        }
+
+        // TODO(alokp): Optimize this.
+        // There is no need to search for macro params every time.
+        // The param index can be cached with the replacement token.
+        Macro::Parameters::const_iterator iter =
+            std::find(macro.parameters.begin(), macro.parameters.end(), repl.text);
+        if (iter == macro.parameters.end())
+        {
+            replacements->push_back(repl);
+            continue;
+        }
+
+        std::size_t iArg    = std::distance(macro.parameters.begin(), iter);
+        const MacroArg &arg = args[iArg];
+        if (arg.empty())
+        {
+            continue;
+        }
+        std::size_t iRepl = replacements->size();
+        replacements->insert(replacements->end(), arg.begin(), arg.end());
+        // The replacement token inherits padding properties from
+        // macro replacement token.
+        replacements->at(iRepl).setHasLeadingSpace(repl.hasLeadingSpace());
+    }
+}
+
+MacroExpander::MacroContext::MacroContext() : macro(0), index(0) {}
+
+MacroExpander::MacroContext::~MacroContext() {}
+
+bool MacroExpander::MacroContext::empty() const
+{
+    return index == replacements.size();
+}
+
+const Token &MacroExpander::MacroContext::get()
+{
+    return replacements[index++];
+}
+
+void MacroExpander::MacroContext::unget()
+{
+    ASSERT(index > 0);
+    --index;
+}
+
+}  // namespace pp
+
+}  // namespace angle