Merge pull request #8 from alexcrichton/merge

Another merge of the upstream 8.x branch

Author: alexcrichton

clang-tools-extra/docs/ReleaseNotes.rst

@@ -1,19 +1,13 @@
-===================================================
-Extra Clang Tools 8.0.0 (In-Progress) Release Notes
-===================================================
+=====================================
+Extra Clang Tools 8.0.0 Release Notes
+=====================================
 
 .. contents::
    :local:
    :depth: 3
 
 Written by the `LLVM Team <https://llvm.org/>`_
 
-.. warning::
-
-   These are in-progress notes for the upcoming Extra Clang Tools 8 release.
-   Release notes for previous releases can be found on
-   `the Download Page <https://releases.llvm.org/download.html>`_.
-
 Introduction
 ============
 
@@ -27,11 +21,6 @@ For more information about Clang or LLVM, including information about
 the latest release, please see the `Clang Web Site <https://clang.llvm.org>`_ or
 the `LLVM Web Site <https://llvm.org>`_.
 
-Note that if you are reading this file from a Subversion checkout or the
-main Clang web page, this document applies to the *next* release, not
-the current one. To see the release notes for a specific release, please
-see the `releases page <https://llvm.org/releases/>`_.
-
 What's New in Extra Clang Tools 8.0.0?
 ======================================
 

clang-tools-extra/docs/index.rst

@@ -29,24 +29,6 @@ Contents
    clang-doc
 
 
-Doxygen Documentation
-=====================
-The Doxygen documentation describes the **internal** software that makes up the
-tools of clang-tools-extra, not the **external** use of these tools. The Doxygen
-documentation contains no instructions about how to use the tools, only the APIs
-that make up the software. For usage instructions, please see the user's guide
-or reference manual for each tool.
-
-* `Doxygen documentation`_
-
-.. _`Doxygen documentation`: doxygen/annotated.html
-
-.. note::
-    This documentation is generated directly from the source code with doxygen.
-    Since the tools of clang-tools-extra are constantly under active
-    development, what you're about to read is out of date!
-
-
 Indices and tables
 ==================
 

clang/docs/ReleaseNotes.rst

@@ -1,19 +1,13 @@
-=======================================
-Clang 8.0.0 (In-Progress) Release Notes
-=======================================
+=========================
+Clang 8.0.0 Release Notes
+=========================
 
 .. contents::
    :local:
    :depth: 2
 
 Written by the `LLVM Team <https://llvm.org/>`_
 
-.. warning::
-
-   These are in-progress notes for the upcoming Clang 8 release.
-   Release notes for previous releases can be found on
-   `the Download Page <https://releases.llvm.org/download.html>`_.
-
 Introduction
 ============
 
@@ -30,11 +24,6 @@ For more information about Clang or LLVM, including information about the
 latest release, please see the `Clang Web Site <https://clang.llvm.org>`_ or the
 `LLVM Web Site <https://llvm.org>`_.
 
-Note that if you are reading this file from a Subversion checkout or the
-main Clang web page, this document applies to the *next* release, not
-the current one. To see the release notes for a specific release, please
-see the `releases page <https://llvm.org/releases/>`_.
-
 What's New in Clang 8.0.0?
 ==========================
 
@@ -50,7 +39,38 @@ Major New Features
   profile data captured for one version of a program to be applied
   when building another version where symbols have changed (for
   example, due to renaming a class or namespace).
-  See the :doc:`UsersManual` for details.
+  See the :ref:`UsersManual <profile_remapping>` for details.
+
+- Clang has new options to initialize automatic variables with either a pattern or with zeroes. The default is still that automatic variables are uninitialized. This isn't meant to change the semantics of C and C++. Rather, it's meant to be a last resort when programmers inadvertently have some undefined behavior in their code. These options aim to make undefined behavior hurt less, which security-minded people will be very happy about. Notably, this means that there's no inadvertent information leak when:
+
+    * The compiler re-uses stack slots, and a value is used uninitialized.
+
+    * The compiler re-uses a register, and a value is used uninitialized.
+
+    * Stack structs / arrays / unions with padding are copied.
+
+  These options only address stack and register information leaks.
+
+  Caveats:
+
+    * Variables declared in unreachable code and used later aren't initialized. This affects goto statements, Duff's device, and other objectionable uses of switch statements. This should instead be a hard-error in any serious codebase.
+
+    * These options don't affect volatile stack variables.
+
+    * Padding isn't fully handled yet.
+
+  How to use it on the command line:
+
+    * ``-ftrivial-auto-var-init=uninitialized`` (the default)
+
+    * ``-ftrivial-auto-var-init=pattern``
+
+    * ``-ftrivial-auto-var-init=zero`` ``-enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang``
+
+  There is also a new attribute to request a variable to not be initialized, mainly to disable initialization of large stack arrays when deemed too expensive:
+
+    * ``int dont_initialize_me __attribute((uninitialized));``
+
 
 Improvements to Clang's diagnostics
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -131,14 +151,24 @@ Non-comprehensive list of changes in this release
 
 - Improved support for MIPS N32 ABI and MIPS R6 target triples.
 
+- Clang now includes builtin functions for bitwise rotation of common value
+  sizes, such as: `__builtin_rotateleft32
+  <LanguageExtensions.html#builtin-rotateleft>`_
+
+- Improved optimization for the corresponding MSVC compatibility builtins such
+  as ``_rotl()``.
+
 New Compiler Flags
 ------------------
 
+- ``-mspeculative-load-hardening`` Clang now has an option to enable
+  Speculative Load Hardening.
+
 - ``-fprofile-filter-files=[regexes]`` and ``-fprofile-exclude-files=[regexes]``.
 
   Clang has now options to filter or exclude some files when
   instrumenting for gcov-based profiling.
-  See the :doc:`UsersManual` for details.
+  See the `UsersManual <UsersManual.html#cmdoption-fprofile-filter-files>`_ for details.
 
 - When using a custom stack alignment, the ``stackrealign`` attribute is now
   implicitly set on the main function.
@@ -175,7 +205,9 @@ New Pragmas in Clang
 Attribute Changes in Clang
 --------------------------
 
-- ...
+* Clang now supports enabling/disabling speculative load hardening on a
+  per-function basis using the function attribute
+  ``speculative_load_hardening``/``no_speculative_load_hardening``.
 
 Windows Support
 ---------------

clang/docs/UsersManual.rst

@@ -1799,6 +1799,8 @@ In these cases, you can use the flag ``-fno-profile-instr-generate`` (or
 Note that these flags should appear after the corresponding profile
 flags to have an effect.
 
+.. _profile_remapping:
+
 Profile remapping
 ^^^^^^^^^^^^^^^^^
 

clang/include/clang/AST/Expr.h

@@ -2577,6 +2577,11 @@ class CallExpr : public Expr {
     NumArgs = NewNumArgs;
   }
 
+  /// Bluntly set a new number of arguments without doing any checks whatsoever.
+  /// Only used during construction of a CallExpr in a few places in Sema.
+  /// FIXME: Find a way to remove it.
+  void setNumArgsUnsafe(unsigned NewNumArgs) { NumArgs = NewNumArgs; }
+
   typedef ExprIterator arg_iterator;
   typedef ConstExprIterator const_arg_iterator;
   typedef llvm::iterator_range<arg_iterator> arg_range;

clang/include/clang/Basic/Attr.td

@@ -103,13 +103,6 @@ def ObjCInstanceMethod : SubsetSubject<ObjCMethod,
                                        [{S->isInstanceMethod()}],
                                        "Objective-C instance methods">;
 
-def ObjCInterfaceDeclInitMethod : SubsetSubject<ObjCMethod,
-                               [{S->getMethodFamily() == OMF_init &&
-                                 (isa<ObjCInterfaceDecl>(S->getDeclContext()) ||
-                                  (isa<ObjCCategoryDecl>(S->getDeclContext()) &&
-            cast<ObjCCategoryDecl>(S->getDeclContext())->IsClassExtension()))}],
-            "init methods of interface or class extension declarations">;
-
 def Struct : SubsetSubject<Record,
                            [{!S->isUnion()}], "structs">;
 
@@ -1762,7 +1755,7 @@ def ObjCExplicitProtocolImpl : InheritableAttr {
 
 def ObjCDesignatedInitializer : Attr {
   let Spellings = [Clang<"objc_designated_initializer">];
-  let Subjects = SubjectList<[ObjCInterfaceDeclInitMethod], ErrorDiag>;
+  let Subjects = SubjectList<[ObjCMethod], ErrorDiag>;
   let Documentation = [Undocumented];
 }
 

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -3460,6 +3460,9 @@ def warn_objc_secondary_init_missing_init_call : Warning<
 def warn_objc_implementation_missing_designated_init_override : Warning<
   "method override for the designated initializer of the superclass %objcinstance0 not found">,
   InGroup<ObjCDesignatedInit>;
+def err_designated_init_attr_non_init : Error<
+  "'objc_designated_initializer' attribute only applies to init methods "
+  "of interface or class extension declarations">;
 
 // objc_bridge attribute diagnostics.
 def err_objc_attr_not_id : Error<

clang/include/clang/Parse/Parser.h

@@ -360,11 +360,6 @@ class Parser : public CodeCompletionHandler {
   /// just a regular sub-expression.
   SourceLocation ExprStatementTokLoc;
 
-  /// Tests whether an expression value is discarded based on token lookahead.
-  /// It will return true if the lexer is currently processing the })
-  /// terminating a GNU statement expression and false otherwise.
-  bool isExprValueDiscarded();
-
 public:
   Parser(Preprocessor &PP, Sema &Actions, bool SkipFunctionBodies);
   ~Parser() override;

clang/include/clang/Sema/Sema.h

@@ -1369,7 +1369,6 @@ class Sema {
   void PopCompoundScope();
 
   sema::CompoundScopeInfo &getCurCompoundScope() const;
-  bool isCurCompoundStmtAStmtExpr() const;
 
   bool hasAnyUnrecoverableErrorsInThisFunction() const;
 
@@ -3690,17 +3689,16 @@ class Sema {
     return MakeFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation());
   }
   FullExprArg MakeFullExpr(Expr *Arg, SourceLocation CC) {
-    return FullExprArg(
-        ActOnFinishFullExpr(Arg, CC, /*DiscardedValue*/ false).get());
+    return FullExprArg(ActOnFinishFullExpr(Arg, CC).get());
   }
   FullExprArg MakeFullDiscardedValueExpr(Expr *Arg) {
     ExprResult FE =
-        ActOnFinishFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation(),
-                            /*DiscardedValue*/ true);
+      ActOnFinishFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation(),
+                          /*DiscardedValue*/ true);
     return FullExprArg(FE.get());
   }
 
-  StmtResult ActOnExprStmt(ExprResult Arg, bool DiscardedValue = true);
+  StmtResult ActOnExprStmt(ExprResult Arg);
   StmtResult ActOnExprStmtError();
 
   StmtResult ActOnNullStmt(SourceLocation SemiLoc,
@@ -5346,12 +5344,13 @@ class Sema {
   CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
                                  bool BoundToLvalueReference);
 
-  ExprResult ActOnFinishFullExpr(Expr *Expr, bool DiscardedValue) {
-    return ActOnFinishFullExpr(
-        Expr, Expr ? Expr->getExprLoc() : SourceLocation(), DiscardedValue);
+  ExprResult ActOnFinishFullExpr(Expr *Expr) {
+    return ActOnFinishFullExpr(Expr, Expr ? Expr->getExprLoc()
+                                          : SourceLocation());
   }
   ExprResult ActOnFinishFullExpr(Expr *Expr, SourceLocation CC,
-                                 bool DiscardedValue, bool IsConstexpr = false);
+                                 bool DiscardedValue = false,
+                                 bool IsConstexpr = false);
   StmtResult ActOnFinishFullStmt(Stmt *Stmt);
 
   // Marks SS invalid if it represents an incomplete type.

clang/lib/CodeGen/CGDecl.cpp

@@ -1620,8 +1620,9 @@ void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
   bool capturedByInit =
       Init && emission.IsEscapingByRef && isCapturedBy(D, Init);
 
-  Address Loc =
-      capturedByInit ? emission.Addr : emission.getObjectAddress(*this);
+  bool locIsByrefHeader = !capturedByInit;
+  const Address Loc =
+      locIsByrefHeader ? emission.getObjectAddress(*this) : emission.Addr;
 
   // Note: constexpr already initializes everything correctly.
   LangOptions::TrivialAutoVarInitKind trivialAutoVarInit =
@@ -1637,7 +1638,7 @@ void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
       return;
 
     // Only initialize a __block's storage: we always initialize the header.
-    if (emission.IsEscapingByRef)
+    if (emission.IsEscapingByRef && !locIsByrefHeader)
       Loc = emitBlockByrefAddress(Loc, &D, /*follow=*/false);
 
     CharUnits Size = getContext().getTypeSizeInChars(type);
@@ -1745,10 +1746,9 @@ void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
   }
 
   llvm::Type *BP = CGM.Int8Ty->getPointerTo(Loc.getAddressSpace());
-  if (Loc.getType() != BP)
-    Loc = Builder.CreateBitCast(Loc, BP);
-
-  emitStoresForConstant(CGM, D, Loc, isVolatile, Builder, constant);
+  emitStoresForConstant(
+      CGM, D, (Loc.getType() == BP) ? Loc : Builder.CreateBitCast(Loc, BP),
+      isVolatile, Builder, constant);
 }
 
 /// Emit an expression as an initializer for an object (variable, field, etc.)