Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 256 insertions, 0 deletions

diff --git a/build/clang-plugin/DanglingOnTemporaryChecker.cpp b/build/clang-plugin/DanglingOnTemporaryChecker.cpp
new file mode 100644
index 0000000000..96d85ef4c0
--- /dev/null
+++ b/build/clang-plugin/DanglingOnTemporaryChecker.cpp
@@ -0,0 +1,256 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DanglingOnTemporaryChecker.h"
+#include "CustomMatchers.h"
+#include "VariableUsageHelpers.h"
+
+void DanglingOnTemporaryChecker::registerMatchers(MatchFinder *AstMatcher) {
+  ////////////////////////////////////////
+  // Quick annotation conflict checkers //
+  ////////////////////////////////////////
+
+  AstMatcher->addMatcher(
+      // This is a matcher on a method declaration,
+      cxxMethodDecl(
+          // which is marked as no dangling on temporaries,
+          noDanglingOnTemporaries(),
+
+          // and which is && ref-qualified.
+          isRValueRefQualified(),
+
+          decl().bind("invalidMethodRefQualified")),
+      this);
+
+  AstMatcher->addMatcher(
+      // This is a matcher on a method declaration,
+      cxxMethodDecl(
+          // which is marked as no dangling on temporaries,
+          noDanglingOnTemporaries(),
+
+          // which returns a primitive type,
+          returns(builtinType()),
+
+          // and which doesn't return a pointer.
+          unless(returns(pointerType())),
+
+          decl().bind("invalidMethodPointer")),
+      this);
+
+  //////////////////
+  // Main checker //
+  //////////////////
+
+  auto hasParentCall = hasParent(
+      expr(anyOf(cxxOperatorCallExpr(
+                     // If we're in a lamda, we may have an operator call
+                     // expression ancestor in the AST, but the temporary we're
+                     // matching against is not going to have the same lifetime
+                     // as the constructor call.
+                     unless(has(expr(ignoreTrivials(lambdaExpr())))),
+                     expr().bind("parentOperatorCallExpr")),
+                 callExpr(
+                     // If we're in a lamda, we may have a call expression
+                     // ancestor in the AST, but the temporary we're matching
+                     // against is not going to have the same lifetime as the
+                     // function call.
+                     unless(has(expr(ignoreTrivials(lambdaExpr())))),
+                     expr().bind("parentCallExpr")),
+                 objcMessageExpr(
+                     // If we're in a lamda, we may have an objc message
+                     // expression ancestor in the AST, but the temporary we're
+                     // matching against is not going to have the same lifetime
+                     // as the function call.
+                     unless(has(expr(ignoreTrivials(lambdaExpr())))),
+                     expr().bind("parentObjCMessageExpr")),
+                 cxxConstructExpr(
+                     // If we're in a lamda, we may have a construct expression
+                     // ancestor in the AST, but the temporary we're matching
+                     // against is not going to have the same lifetime as the
+                     // constructor call.
+                     unless(has(expr(ignoreTrivials(lambdaExpr())))),
+                     expr().bind("parentConstructExpr")))));
+
+  AstMatcher->addMatcher(
+      // This is a matcher on a method call,
+      cxxMemberCallExpr(
+          // which is in first party code,
+          isFirstParty(),
+
+          // and which is performed on a temporary,
+          on(allOf(unless(hasType(pointerType())), isTemporary(),
+                   // but which is not `this`.
+                   unless(cxxThisExpr()))),
+
+          // and which is marked as no dangling on temporaries.
+          callee(cxxMethodDecl(noDanglingOnTemporaries())),
+
+          expr().bind("memberCallExpr"),
+
+          // We optionally match a parent call expression or a parent construct
+          // expression because using a temporary inside a call is fine as long
+          // as the pointer doesn't escape the function call.
+          anyOf(
+              // This is the case where the call is the direct parent, so we
+              // know that the member call expression is the argument.
+              allOf(hasParentCall, expr().bind("parentCallArg")),
+
+              // This is the case where the call is not the direct parent, so we
+              // get its child to know in which argument tree we are.
+              hasAncestor(expr(hasParentCall, expr().bind("parentCallArg"))),
+              // To make it optional.
+              anything())),
+      this);
+}
+
+void DanglingOnTemporaryChecker::check(const MatchFinder::MatchResult &Result) {
+  ///////////////////////////////////////
+  // Quick annotation conflict checker //
+  ///////////////////////////////////////
+
+  const char *ErrorInvalidRefQualified = "methods annotated with "
+                                         "MOZ_NO_DANGLING_ON_TEMPORARIES "
+                                         "cannot be && ref-qualified";
+
+  const char *ErrorInvalidPointer = "methods annotated with "
+                                    "MOZ_NO_DANGLING_ON_TEMPORARIES must "
+                                    "return a pointer";
+
+  if (auto InvalidRefQualified =
+          Result.Nodes.getNodeAs<CXXMethodDecl>("invalidMethodRefQualified")) {
+    diag(InvalidRefQualified->getLocation(), ErrorInvalidRefQualified,
+         DiagnosticIDs::Error);
+    return;
+  }
+
+  if (auto InvalidPointer =
+          Result.Nodes.getNodeAs<CXXMethodDecl>("invalidMethodPointer")) {
+    diag(InvalidPointer->getLocation(), ErrorInvalidPointer,
+         DiagnosticIDs::Error);
+    return;
+  }
+
+  //////////////////
+  // Main checker //
+  //////////////////
+
+  const char *Error = "calling `%0` on a temporary, potentially allowing use "
+                      "after free of the raw pointer";
+
+  const char *EscapeStmtNote =
+      "the raw pointer escapes the function scope here";
+
+  const ObjCMessageExpr *ParentObjCMessageExpr =
+      Result.Nodes.getNodeAs<ObjCMessageExpr>("parentObjCMessageExpr");
+
+  // We don't care about cases in ObjC message expressions.
+  if (ParentObjCMessageExpr) {
+    return;
+  }
+
+  const CXXMemberCallExpr *MemberCall =
+      Result.Nodes.getNodeAs<CXXMemberCallExpr>("memberCallExpr");
+
+  const CallExpr *ParentCallExpr =
+      Result.Nodes.getNodeAs<CallExpr>("parentCallExpr");
+  const CXXConstructExpr *ParentConstructExpr =
+      Result.Nodes.getNodeAs<CXXConstructExpr>("parentConstructExpr");
+  const CXXOperatorCallExpr *ParentOperatorCallExpr =
+      Result.Nodes.getNodeAs<CXXOperatorCallExpr>("parentOperatorCallExpr");
+  const Expr *ParentCallArg = Result.Nodes.getNodeAs<Expr>("parentCallArg");
+
+  // Just in case.
+  if (!MemberCall) {
+    return;
+  }
+
+  // If we have a parent call, we check whether or not we escape the function
+  // being called.
+  if (ParentOperatorCallExpr || ParentCallExpr || ParentConstructExpr) {
+    // Just in case.
+    if (!ParentCallArg) {
+      return;
+    }
+
+    // No default constructor so we can't construct it using if/else.
+    auto FunctionEscapeData =
+        ParentOperatorCallExpr
+            ? escapesFunction(ParentCallArg, ParentOperatorCallExpr)
+            : ParentCallExpr
+                  ? escapesFunction(ParentCallArg, ParentCallExpr)
+                  : escapesFunction(ParentCallArg, ParentConstructExpr);
+
+    // If there was an error in the escapesFunction call.
+    if (std::error_code ec = FunctionEscapeData.getError()) {
+      // FIXME: For now we ignore the variadic case and just consider that the
+      // argument doesn't escape the function. Same for the case where we can't
+      // find the function declaration or if the function is builtin.
+      if (static_cast<EscapesFunctionError>(ec.value()) ==
+              EscapesFunctionError::FunctionIsVariadic ||
+          static_cast<EscapesFunctionError>(ec.value()) ==
+              EscapesFunctionError::FunctionDeclNotFound ||
+          static_cast<EscapesFunctionError>(ec.value()) ==
+              EscapesFunctionError::FunctionIsBuiltin) {
+        return;
+      }
+
+      // We emit the internal checker error and return.
+      diag(MemberCall->getExprLoc(),
+           std::string(ec.category().name()) + " error: " + ec.message(),
+           DiagnosticIDs::Error);
+      return;
+    }
+
+    // We deconstruct the function escape data.
+    const Stmt *EscapeStmt;
+    const Decl *EscapeDecl;
+    std::tie(EscapeStmt, EscapeDecl) = *FunctionEscapeData;
+
+    // If we didn't escape a parent function, we're done: we don't emit any
+    // diagnostic.
+    if (!EscapeStmt || !EscapeDecl) {
+      return;
+    }
+
+    // We emit the error diagnostic indicating that we are calling the method
+    // temporary.
+    diag(MemberCall->getExprLoc(), Error, DiagnosticIDs::Error)
+        << MemberCall->getMethodDecl()->getName()
+        << MemberCall->getSourceRange();
+
+    // We indicate the escape statement.
+    diag(EscapeStmt->getBeginLoc(), EscapeStmtNote, DiagnosticIDs::Note)
+        << EscapeStmt->getSourceRange();
+
+    // We build the escape note along with its source range.
+    StringRef EscapeDeclNote;
+    SourceRange EscapeDeclRange;
+    if (isa<ParmVarDecl>(EscapeDecl)) {
+      EscapeDeclNote = "through the parameter declared here";
+      EscapeDeclRange = EscapeDecl->getSourceRange();
+    } else if (isa<VarDecl>(EscapeDecl)) {
+      EscapeDeclNote = "through the variable declared here";
+      EscapeDeclRange = EscapeDecl->getSourceRange();
+    } else if (isa<FieldDecl>(EscapeDecl)) {
+      EscapeDeclNote = "through the field declared here";
+      EscapeDeclRange = EscapeDecl->getSourceRange();
+    } else if (auto FuncDecl = dyn_cast<FunctionDecl>(EscapeDecl)) {
+      EscapeDeclNote = "through the return value of the function declared here";
+      EscapeDeclRange = FuncDecl->getReturnTypeSourceRange();
+    } else {
+      return;
+    }
+
+    // We emit the declaration note indicating through which decl the argument
+    // escapes.
+    diag(EscapeDecl->getLocation(), EscapeDeclNote, DiagnosticIDs::Note)
+        << EscapeDeclRange;
+  } else {
+    // We emit the error diagnostic indicating that we are calling the method
+    // temporary.
+    diag(MemberCall->getExprLoc(), Error, DiagnosticIDs::Error)
+        << MemberCall->getMethodDecl()->getName()
+        << MemberCall->getSourceRange();
+  }
+}