Reland "[clang-cl] Accept `#pragma warning(disable : N)` for some N"

This reverts commit 0cd9d8a48b and
adds the changes described in https://reviews.llvm.org/D110668#3034461.

clang/include/clang/Basic/CLWarnings.h

@@ -0,0 +1,26 @@
+//===--- CLWarnings.h - Maps some cl.exe warning ids  -----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_BASIC_CLWARNINGS_H
+#define LLVM_CLANG_BASIC_CLWARNINGS_H
+
+#include "llvm/ADT/Optional.h"
+
+namespace clang {
+
+namespace diag {
+enum class Group;
+}
+
+/// For cl.exe warning IDs that cleany map to clang diagnostic groups,
+/// returns the corresponding group. Else, returns an empty Optional.
+llvm::Optional<diag::Group> diagGroupFromCLWarningID(unsigned);
+
+} // end namespace clang
+
+#endif // LLVM_CLANG_BASIC_CLWARNINGS_H

clang/include/clang/Basic/Diagnostic.h

@@ -807,6 +807,9 @@ public:
   bool setSeverityForGroup(diag::Flavor Flavor, StringRef Group,
                            diag::Severity Map,
                            SourceLocation Loc = SourceLocation());
+  bool setSeverityForGroup(diag::Flavor Flavor, diag::Group Group,
+                           diag::Severity Map,
+                           SourceLocation Loc = SourceLocation());
 
   /// Set the warning-as-error flag for the given diagnostic group.
   ///

clang/include/clang/Basic/DiagnosticCategories.h

@@ -19,6 +19,13 @@ namespace clang {
 #undef GET_CATEGORY_TABLE
       DiagCat_NUM_CATEGORIES
     };
+
+    enum class Group {
+#define DIAG_ENTRY(GroupName, FlagNameOffset, Members, SubGroups) GroupName,
+#include "clang/Basic/DiagnosticGroups.inc"
+#undef CATEGORY
+#undef DIAG_ENTRY
+    };
   }  // end namespace diag
 }  // end namespace clang
 

clang/include/clang/Basic/DiagnosticGroups.td

@@ -396,6 +396,7 @@ def Dangling : DiagGroup<"dangling", [DanglingField,
                                       DanglingGsl,
                                       ReturnStackAddress]>;
 def DistributedObjectModifiers : DiagGroup<"distributed-object-modifiers">;
+def DllexportExplicitInstantiationDecl : DiagGroup<"dllexport-explicit-instantiation-decl">;
 def ExcessInitializers : DiagGroup<"excess-initializers">;
 def ExpansionToDefined : DiagGroup<"expansion-to-defined">;
 def FlagEnum : DiagGroup<"flag-enum">;

clang/include/clang/Basic/DiagnosticIDs.h

@@ -25,6 +25,8 @@ namespace clang {
 
   // Import the diagnostic enums themselves.
   namespace diag {
+    enum class Group;
+
     // Size of each of the diagnostic categories.
     enum {
       DIAG_SIZE_COMMON        =  300,
@@ -224,6 +226,10 @@ public:
   ///
   static bool isBuiltinExtensionDiag(unsigned DiagID, bool &EnabledByDefault);
 
+  /// Given a group ID, returns the flag that toggles the group.
+  /// For example, for Group::DeprecatedDeclarations, returns
+  /// "deprecated-declarations".
+  static StringRef getWarningOptionForGroup(diag::Group);
 
   /// Return the lowest-level warning option that enables the specified
   /// diagnostic.

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -3396,7 +3396,7 @@ def warn_attribute_dllimport_static_field_definition : Warning<
   InGroup<DiagGroup<"dllimport-static-field-def">>;
 def warn_attribute_dllexport_explicit_instantiation_decl : Warning<
   "explicit instantiation declaration should not be 'dllexport'">,
-  InGroup<DiagGroup<"dllexport-explicit-instantiation-decl">>;
+  InGroup<DllexportExplicitInstantiationDecl>;
 def warn_attribute_dllexport_explicit_instantiation_def : Warning<
   "'dllexport' attribute ignored on explicit instantiation definition">,
   InGroup<IgnoredAttributes>;

clang/include/clang/Driver/Options.td

@@ -6106,16 +6106,7 @@ def _SLASH_WX_ : CLFlag<"WX-">,
   HelpText<"Do not treat warnings as errors (default)">,
   Alias<W_Joined>, AliasArgs<["no-error"]>;
 def _SLASH_w_flag : CLFlag<"w">, HelpText<"Disable all warnings">, Alias<w>;
-def _SLASH_wd4005 : CLFlag<"wd4005">, Alias<W_Joined>,
-  AliasArgs<["no-macro-redefined"]>;
-def _SLASH_wd4018 : CLFlag<"wd4018">, Alias<W_Joined>,
-  AliasArgs<["no-sign-compare"]>;
-def _SLASH_wd4100 : CLFlag<"wd4100">, Alias<W_Joined>,
-  AliasArgs<["no-unused-parameter"]>;
-def _SLASH_wd4910 : CLFlag<"wd4910">, Alias<W_Joined>,
-  AliasArgs<["no-dllexport-explicit-instantiation-decl"]>;
-def _SLASH_wd4996 : CLFlag<"wd4996">, Alias<W_Joined>,
-  AliasArgs<["no-deprecated-declarations"]>;
+def _SLASH_wd : CLCompileJoined<"wd">;
 def _SLASH_vd : CLJoined<"vd">, HelpText<"Control vtordisp placement">,
   Alias<vtordisp_mode_EQ>;
 def _SLASH_X : CLFlag<"X">,

clang/lib/Basic/CLWarnings.cpp

@@ -0,0 +1,28 @@
+//===--- CLWarnings.h - Maps some cl.exe warning ids  -----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the Diagnostic-related interfaces.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/CLWarnings.h"
+#include "clang/Basic/DiagnosticCategories.h"
+
+using namespace clang;
+
+llvm::Optional<diag::Group>
+clang::diagGroupFromCLWarningID(unsigned CLWarningID) {
+  switch (CLWarningID) {
+  case 4005: return diag::Group::MacroRedefined;
+  case 4018: return diag::Group::SignCompare;
+  case 4100: return diag::Group::UnusedParameter;
+  case 4910: return diag::Group::DllexportExplicitInstantiationDecl;
+  case 4996: return diag::Group::DeprecatedDeclarations;
+  }
+  return {};
+}

clang/lib/Basic/CMakeLists.txt

@@ -39,6 +39,7 @@ endif()
 add_clang_library(clangBasic
   Attributes.cpp
   Builtins.cpp
+  CLWarnings.cpp
   CharInfo.cpp
   CodeGenOptions.cpp
   Cuda.cpp

clang/lib/Basic/Diagnostic.cpp

@@ -408,6 +408,14 @@ bool DiagnosticsEngine::setSeverityForGroup(diag::Flavor Flavor,
   return false;
 }
 
+bool DiagnosticsEngine::setSeverityForGroup(diag::Flavor Flavor,
+                                            diag::Group Group,
+                                            diag::Severity Map,
+                                            SourceLocation Loc) {
+  return setSeverityForGroup(Flavor, Diags->getWarningOptionForGroup(Group),
+                             Map, Loc);
+}
+
 bool DiagnosticsEngine::setDiagnosticGroupWarningAsError(StringRef Group,
                                                          bool Enabled) {
   // If we are enabling this feature, just set the diagnostic mappings to map to

clang/lib/Basic/DiagnosticIDs.cpp

@@ -609,17 +609,23 @@ namespace {
 
 // Second the table of options, sorted by name for fast binary lookup.
 static const WarningOption OptionTable[] = {
-#define GET_DIAG_TABLE
+#define DIAG_ENTRY(GroupName, FlagNameOffset, Members, SubGroups)              \
+  {FlagNameOffset, Members, SubGroups},
 #include "clang/Basic/DiagnosticGroups.inc"
-#undef GET_DIAG_TABLE
+#undef DIAG_ENTRY
 };
 
+StringRef DiagnosticIDs::getWarningOptionForGroup(diag::Group Group) {
+  return OptionTable[static_cast<int>(Group)].getName();
+}
+
 /// getWarningOptionForDiag - Return the lowest-level warning option that
 /// enables the specified diagnostic.  If there is no -Wfoo flag that controls
 /// the diagnostic, this returns null.
 StringRef DiagnosticIDs::getWarningOptionForDiag(unsigned DiagID) {
   if (const StaticDiagInfoRec *Info = GetDiagInfo(DiagID))
-    return OptionTable[Info->getOptionGroupIndex()].getName();
+    return getWarningOptionForGroup(
+        static_cast<diag::Group>(Info->getOptionGroupIndex()));
   return StringRef();
 }
 

clang/lib/Driver/ToolChains/Clang.cpp

@@ -22,6 +22,7 @@
 #include "Hexagon.h"
 #include "MSP430.h"
 #include "PS4CPU.h"
+#include "clang/Basic/CLWarnings.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/CodeGenOptions.h"
 #include "clang/Basic/LangOptions.h"
@@ -5438,7 +5439,26 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
 
   Args.AddAllArgs(CmdArgs, options::OPT_R_Group);
 
-  Args.AddAllArgs(CmdArgs, options::OPT_W_Group);
+  for (const Arg *A :
+       Args.filtered(options::OPT_W_Group, options::OPT__SLASH_wd)) {
+    A->claim();
+    if (A->getOption().getID() == options::OPT__SLASH_wd) {
+      unsigned WarningNumber;
+      if (StringRef(A->getValue()).getAsInteger(10, WarningNumber)) {
+        D.Diag(diag::err_drv_invalid_int_value)
+            << A->getAsString(Args) << A->getValue();
+        continue;
+      }
+
+      if (auto Group = diagGroupFromCLWarningID(WarningNumber)) {
+        CmdArgs.push_back(Args.MakeArgString(
+            "-Wno-" + DiagnosticIDs::getWarningOptionForGroup(*Group)));
+      }
+      continue;
+    }
+    A->render(Args, CmdArgs);
+  }
+
   if (Args.hasFlag(options::OPT_pedantic, options::OPT_no_pedantic, false))
     CmdArgs.push_back("-pedantic");
   Args.AddLastArg(CmdArgs, options::OPT_pedantic_errors);

clang/lib/Lex/Pragma.cpp

@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Lex/Pragma.h"
+#include "clang/Basic/CLWarnings.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/DiagnosticLex.h"
 #include "clang/Basic/FileManager.h"
@@ -1413,12 +1414,15 @@ struct PragmaWarningHandler : public PragmaHandler {
           return;
         }
       }
+      PP.getDiagnostics().pushMappings(DiagLoc);
       if (Callbacks)
         Callbacks->PragmaWarningPush(DiagLoc, Level);
     } else if (II && II->isStr("pop")) {
       // #pragma warning( pop )
       PP.Lex(Tok);
-      if (Callbacks)
+      if (!PP.getDiagnostics().popMappings(DiagLoc))
+        PP.Diag(Tok, diag::warn_pragma_diagnostic_cannot_pop);
+      else if (Callbacks)
         Callbacks->PragmaWarningPop(DiagLoc);
     } else {
       // #pragma warning( warning-specifier : warning-number-list
@@ -1482,6 +1486,22 @@ struct PragmaWarningHandler : public PragmaHandler {
           }
           Ids.push_back(int(Value));
         }
+
+        // Only act on disable for now.
+        diag::Severity SV = diag::Severity();
+        if (Specifier == PPCallbacks::PWS_Disable)
+          SV = diag::Severity::Ignored;
+        if (SV != diag::Severity())
+          for (int Id : Ids) {
+            if (auto Group = diagGroupFromCLWarningID(Id)) {
+              bool unknownDiag = PP.getDiagnostics().setSeverityForGroup(
+                  diag::Flavor::WarningOrError, *Group, SV, DiagLoc);
+              assert(!unknownDiag &&
+                     "wd table should only contain known diags");
+              (void)unknownDiag;
+            }
+          }
+
         if (Callbacks)
           Callbacks->PragmaWarning(DiagLoc, Specifier, Ids);
 

clang/test/Driver/cl-options.c

@@ -353,12 +353,13 @@
 // CHECK-C11: -std=c11
 
 // For some warning ids, we can map from MSVC warning to Clang warning.
-// RUN: %clang_cl -wd4005 -wd4100 -wd4910 -wd4996 -### -- %s 2>&1 | FileCheck -check-prefix=Wno %s
+// RUN: %clang_cl -wd4005 -wd4100 -wd4910 -wd4996 -wd12345678 -### -- %s 2>&1 | FileCheck -check-prefix=Wno %s
 // Wno: "-cc1"
 // Wno: "-Wno-macro-redefined"
 // Wno: "-Wno-unused-parameter"
 // Wno: "-Wno-dllexport-explicit-instantiation-decl"
 // Wno: "-Wno-deprecated-declarations"
+// Wno-NOT: "-wd
 
 // Ignored options. Check that we don't get "unused during compilation" errors.
 // RUN: %clang_cl /c \

clang/test/Sema/pragma-warning.cpp

@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc -fms-extensions -fsyntax-only -verify %s
+
+[[deprecated]] void f() {} // expected-note 2 {{marked deprecated here}}
+
+#define From__pragma() \
+  __pragma(warning(push)) \
+  __pragma(warning(disable:4996)) \
+  f(); \
+  __pragma(warning(pop))
+
+void g() {
+  f(); // expected-warning {{deprecated}}
+
+#pragma warning(push)
+#pragma warning(disable: 4996)
+  f(); // no diag
+
+#pragma warning(disable: 49960000)
+#pragma warning(pop)
+
+  f(); // expected-warning {{deprecated}}
+
+  From__pragma(); // no diag
+}

clang/tools/diagtool/DiagnosticNames.cpp

@@ -66,9 +66,10 @@ const DiagnosticRecord &diagtool::getDiagnosticForID(short DiagID) {
 
 // Second the table of options, sorted by name for fast binary lookup.
 static const GroupRecord OptionTable[] = {
-#define GET_DIAG_TABLE
+#define DIAG_ENTRY(GroupName, FlagNameOffset, Members, SubGroups)              \
+  {FlagNameOffset, Members, SubGroups},
 #include "clang/Basic/DiagnosticGroups.inc"
-#undef GET_DIAG_TABLE
+#undef DIAG_ENTRY
 };
 
 llvm::StringRef GroupRecord::getName() const {

clang/utils/TableGen/ClangDiagnosticsEmitter.cpp

@@ -129,6 +129,7 @@ namespace {
   };
 
   struct GroupInfo {
+    llvm::StringRef GroupName;
     std::vector<const Record*> DiagsInGroup;
     std::vector<std::string> SubGroups;
     unsigned IDNo;
@@ -174,6 +175,7 @@ static void groupDiagnostics(const std::vector<Record*> &Diags,
     Record *Group = DiagGroups[i];
     GroupInfo &GI =
         DiagsInGroup[std::string(Group->getValueAsString("GroupName"))];
+    GI.GroupName = Group->getName();
     GI.Defs.push_back(Group);
 
     std::vector<Record*> SubGroups = Group->getValueAsListOfDefs("SubGroups");
@@ -1279,8 +1281,8 @@ void clang::EmitClangDiagsDefs(RecordKeeper &Records, raw_ostream &OS,
     OS << ", \"";
     OS.write_escaped(DiagTextBuilder.buildForDefinition(&R)) << '"';
 
-    // Warning associated with the diagnostic. This is stored as an index into
-    // the alphabetically sorted warning table.
+    // Warning group associated with the diagnostic. This is stored as an index
+    // into the alphabetically sorted warning group table.
     if (DefInit *DI = dyn_cast<DefInit>(R.getValueInit("Group"))) {
       std::map<std::string, GroupInfo>::iterator I = DiagsInGroup.find(
           std::string(DI->getDef()->getValueAsString("GroupName")));
@@ -1487,18 +1489,20 @@ static void emitDiagTable(std::map<std::string, GroupInfo> &DiagsInGroup,
   for (auto const &I: DiagsInGroup)
     MaxLen = std::max(MaxLen, (unsigned)I.first.size());
 
-  OS << "\n#ifdef GET_DIAG_TABLE\n";
+  OS << "\n#ifdef DIAG_ENTRY\n";
   unsigned SubGroupIndex = 1, DiagArrayIndex = 1;
   for (auto const &I: DiagsInGroup) {
     // Group option string.
-    OS << "  { /* ";
+    OS << "DIAG_ENTRY(";
+    OS << I.second.GroupName << " /* ";
+
     if (I.first.find_first_not_of("abcdefghijklmnopqrstuvwxyz"
                                    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                                    "0123456789!@#$%^*-+=:?") !=
         std::string::npos)
       PrintFatalError("Invalid character in diagnostic group '" + I.first +
                       "'");
-    OS << I.first << " */ " << std::string(MaxLen - I.first.size(), ' ');
+    OS << I.first << " */, ";
     // Store a pascal-style length byte at the beginning of the string.
     std::string Name = char(I.first.size()) + I.first;
     OS << GroupNames.GetOrAddStringOffset(Name, false) << ", ";
@@ -1517,7 +1521,7 @@ static void emitDiagTable(std::map<std::string, GroupInfo> &DiagsInGroup,
         DiagArrayIndex += DiagsInPedantic.size();
       DiagArrayIndex += V.size() + 1;
     } else {
-      OS << "/* Empty */     0, ";
+      OS << "0, ";
     }
 
     // Subgroups.
@@ -1530,12 +1534,12 @@ static void emitDiagTable(std::map<std::string, GroupInfo> &DiagsInGroup,
         SubGroupIndex += GroupsInPedantic.size();
       SubGroupIndex += SubGroups.size() + 1;
     } else {
-      OS << "/* Empty */         0";
+      OS << "0";
     }
 
-    OS << " },\n";
+    OS << ")\n";
   }
-  OS << "#endif // GET_DIAG_TABLE\n\n";
+  OS << "#endif // DIAG_ENTRY\n\n";
 }
 
 /// Emit the table of diagnostic categories.

llvm/utils/gn/secondary/clang/lib/Basic/BUILD.gn

@@ -55,6 +55,7 @@ static_library("Basic") {
   sources = [
     "Attributes.cpp",
     "Builtins.cpp",
+    "CLWarnings.cpp",
     "CharInfo.cpp",
     "CodeGenOptions.cpp",
     "Cuda.cpp",