clang-cl: Add a `/showIncludes:user` flag.

[thakis]

Summary

This flag is like /showIncludes, but it only includes user headers and omits system headers (similar to MD and MMD). The motivation is that projects that already track system includes though other means can use this flag to get consistent behavior on Windows and non-Windows, and it saves tools that output /showIncludes output (e.g. ninja) some work.

implementation-wise, this makes HeaderIncludesCallback honor the existing IncludeSystemHeaders bit, and changes the three clients of HeaderIncludesCallback (/showIncludes, -H, CC_PRINT_HEADERS=1) to pass -sys-header-deps to set that bit -- except for /showIncludes:user, which doesn't pass it.

[hans]

Instead of replacing the old cc1 "--show-includes" with "--show-includes -sys-header-deps" -- which looks a little ugly maybe -- would it be simpler to just introduce a new cc1 flag instead, e.g. "--show-user-includes", and just expand /showIncludes:user to that?

[thakis]

This is what -MD passes (which is why the -sys flag already exists), and more orthogonal flags instead of fewer, tangled ones is what we usually go for at the cc1 layer. So I like it more as is.

[thakis]

add one more test

[hans]

In D75093#1891067, @thakis wrote:

This is what -MD passes (which is why the -sys flag already exists), and more orthogonal flags instead of fewer, tangled ones is what we usually go for at the cc1 layer. So I like it more as is.

Ah cool, I didn't realize that. Yes, this makes sense then.

[hans]

Probably worth a mention in clang/docs/ReleaseNotes.rst, and maybe we should call it out in the user manual too, similarly to what we do for /Zc:dllexportInlines-

clang/include/clang/Driver/CLCompatOptions.td

 
 def _SLASH_QUESTION : CLFlag<"?">, Alias<help>,
   HelpText<"Display available options">;
 def _SLASH_Qvec : CLFlag<"Qvec">,
   HelpText<"Enable the loop vectorization passes">, Alias<fvectorize>;
 def _SLASH_Qvec_ : CLFlag<"Qvec-">,
   HelpText<"Disable the loop vectorization passes">, Alias<fno_vectorize>;
 def _SLASH_showIncludes : CLFlag<"showIncludes">,
-  HelpText<"Print info about included files to stderr">,
-  Alias<show_includes>;
+  HelpText<"Print info about included files to stderr">;
+def _SLASH_showIncludes_user : CLFlag<"showIncludes:user">,
+  HelpText<"Like /showIncludes but omit system headers">;
 def _SLASH_showFilenames : CLFlag<"showFilenames">,
   HelpText<"Print the name of each compiled file">;
 def _SLASH_showFilenames_ : CLFlag<"showFilenames-">,
   HelpText<"Do not print the name of each compiled file (default)">;
 def _SLASH_source_charset : CLCompileJoined<"source-charset:">,
   HelpText<"Set source encoding, supports only UTF-8">,
   Alias<finput_charset_EQ>;
 def _SLASH_execution_charset : CLCompileJoined<"execution-charset:">,

clang/lib/Driver/ToolChains/Clang.cpp

           << Unsupported->getOption().getName()
           << "please use -maltivec and include altivec.h explicitly";
     if ((Unsupported = Args.getLastArg(options::OPT_fno_altivec)))
       D.Diag(diag::err_drv_clang_unsupported_opt_faltivec)
           << Unsupported->getOption().getName() << "please use -mno-altivec";
   }
 
   Args.AddAllArgs(CmdArgs, options::OPT_v);
-  Args.AddLastArg(CmdArgs, options::OPT_H);
+
+  if (Args.getLastArg(options::OPT_H)) {
+    CmdArgs.push_back("-H");
+    CmdArgs.push_back("-sys-header-deps");
+  }
+
   if (D.CCPrintHeaders && !D.CCGenDiagnostics) {
     CmdArgs.push_back("-header-include-file");
     CmdArgs.push_back(D.CCPrintHeadersFilename ? D.CCPrintHeadersFilename
                                                : "-");
+    CmdArgs.push_back("-sys-header-deps");
   }
   Args.AddLastArg(CmdArgs, options::OPT_P);
   Args.AddLastArg(CmdArgs, options::OPT_print_ivar_layout);
 
   if (D.CCLogDiagnostics && !D.CCGenDiagnostics) {
     CmdArgs.push_back("-diagnostic-log-file");
     CmdArgs.push_back(D.CCLogDiagnosticsFilename ? D.CCLogDiagnosticsFilename
                                                  : "-");

     CmdArgs.push_back(FlagForCRT.data());
 
     // This provides POSIX compatibility (maps 'open' to '_open'), which most
     // users want.  The /Za flag to cl.exe turns this off, but it's not
     // implemented in clang.
     CmdArgs.push_back("--dependent-lib=oldnames");
   }
 
-  Args.AddLastArg(CmdArgs, options::OPT_show_includes);
+  if (Arg *ShowIncludes =
+          Args.getLastArg(options::OPT__SLASH_showIncludes,
+                          options::OPT__SLASH_showIncludes_user)) {
+    CmdArgs.push_back("--show-includes");
+    if (ShowIncludes->getOption().matches(options::OPT__SLASH_showIncludes))
+      CmdArgs.push_back("-sys-header-deps");
+  }
 
   // This controls whether or not we emit RTTI data for polymorphic types.
   if (Args.hasFlag(options::OPT__SLASH_GR_, options::OPT__SLASH_GR,
                    /*Default=*/false))
     CmdArgs.push_back("-fno-rtti-data");
 
   // This controls whether or not we emit stack-protector instrumentation.
   // In MSVC, Buffer Security Check (/GS) is on by default.

clang/lib/Frontend/DependencyFile.cpp

bool visitInputFile(StringRef Filename, bool IsSystem,
 
     DepCollector.maybeAddDependency(Filename, /*FromModule*/true, IsSystem,
                                    /*IsModuleFile*/false, /*IsMissing*/false);
     return true;
   }
 };
 } // end anonymous namespace
 
-void DependencyCollector::maybeAddDependency(StringRef Filename, bool FromModule,
-                                            bool IsSystem, bool IsModuleFile,
+void DependencyCollector::maybeAddDependency(StringRef Filename,
+                                             bool FromModule, bool IsSystem,
+                                             bool IsModuleFile,
                                              bool IsMissing) {
   if (sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
     addDependency(Filename);
 }
 
 bool DependencyCollector::addDependency(StringRef Filename) {
   if (Seen.insert(Filename).second) {
     Dependencies.push_back(std::string(Filename));
     return true;
   }
   return false;
 }
 
 static bool isSpecialFilename(StringRef Filename) {
   return llvm::StringSwitch<bool>(Filename)
       .Case("<built-in>", true)
       .Case("<stdin>", true)
       .Default(false);
 }
 
 bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule,
                                         bool IsSystem, bool IsModuleFile,
                                         bool IsMissing) {
   return !isSpecialFilename(Filename) &&
          (needSystemDependencies() || !IsSystem);
 }
 
 DependencyCollector::~DependencyCollector() { }
 void DependencyCollector::attachToPreprocessor(Preprocessor &PP) {
   PP.addPPCallbacks(std::make_unique<DepCollectorPPCallbacks>(
       *this, PP.getSourceManager(), PP.getDiagnostics()));

clang/lib/Frontend/HeaderIncludeGen.cpp

for (const auto &Header : DepOpts.ExtraDeps)
     PrintHeaderInfo(OutputFile, Header, ShowDepth, 2, MSStyle);
   PP.addPPCallbacks(std::make_unique<HeaderIncludesCallback>(
       &PP, ShowAllHeaders, OutputFile, DepOpts, OwnsOutputFile, ShowDepth,
       MSStyle));
 }
 
 void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
                                          FileChangeReason Reason,
                                          SrcMgr::CharacteristicKind NewFileType,
                                          FileID PrevFID) {
   // Unless we are exiting a #include, make sure to skip ahead to the line the
   // #include directive was at.
   PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
   if (UserLoc.isInvalid())
     return;
 
   // Adjust the current include depth.
   if (Reason == PPCallbacks::EnterFile) {
void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
   bool ShowHeader = (HasProcessedPredefines ||
                      (ShowAllHeaders && CurrentIncludeDepth > 2));
   unsigned IncludeDepth = CurrentIncludeDepth;
   if (!HasProcessedPredefines)
     --IncludeDepth; // Ignore indent from <built-in>.
   else if (!DepOpts.ShowIncludesPretendHeader.empty())
     ++IncludeDepth; // Pretend inclusion by ShowIncludesPretendHeader.
 
+  if (!DepOpts.IncludeSystemHeaders && isSystem(NewFileType))
+    ShowHeader = false;
+
   // Dump the header include information we are past the predefines buffer or
   // are showing all headers and this isn't the magic implicit <command line>
   // header.
   // FIXME: Identify headers in a more robust way than comparing their name to
   // "<command line>" and "<built-in>" in a bunch of places.
   if (ShowHeader && Reason == PPCallbacks::EnterFile &&
       UserLoc.getFilename() != StringRef("<command line>")) {
     PrintHeaderInfo(OutputFile, UserLoc.getFilename(), ShowDepth, IncludeDepth,
                     MSStyle);
   }
 }

clang/test/Driver/cl-options.c

 // Oy_: -mframe-pointer=all
 
 // RUN: %clang_cl /Qvec -### -- %s 2>&1 | FileCheck -check-prefix=Qvec %s
 // Qvec: -vectorize-loops
 
 // RUN: %clang_cl /Qvec /Qvec- -### -- %s 2>&1 | FileCheck -check-prefix=Qvec_ %s
 // Qvec_-NOT: -vectorize-loops
 
-// RUN: %clang_cl /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes %s
-// showIncludes: --show-includes
+// RUN: %clang_cl /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes_ %s
+// showIncludes_: --show-includes
+// showIncludes_: -sys-header-deps
+
+// RUN: %clang_cl /showIncludes:user -### -- %s 2>&1 | FileCheck -check-prefix=showIncludesUser %s
+// showIncludesUser: --show-includes
+// showIncludesUser-NOT: -sys-header-deps
 
 // RUN: %clang_cl /E /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes_E %s
+// RUN: %clang_cl /E /showIncludes:user -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes_E %s
 // RUN: %clang_cl /EP /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes_E %s
 // RUN: %clang_cl /E /EP /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes_E %s
 // RUN: %clang_cl /EP /P /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes_E %s
 // showIncludes_E-NOT: warning: argument unused during compilation: '--show-includes'
 
 // /source-charset: should warn on everything except UTF-8.
 // RUN: %clang_cl /source-charset:utf-16 -### -- %s 2>&1 | FileCheck -check-prefix=source-charset-utf-16 %s
 // source-charset-utf-16: invalid value 'utf-16' in '/source-charset:utf-16'

clang/test/Frontend/print-header-includes.c

-// RUN: %clang_cc1 -I%S -include Inputs/test3.h -E -H -o /dev/null %s 2> %t.stderr
+// RUN: %clang_cc1 -I%S -include Inputs/test3.h -isystem %S/Inputs/SystemHeaderPrefix \
+// RUN:     -E -H -o /dev/null %s 2> %t.stderr
 // RUN: FileCheck < %t.stderr %s
 
 // CHECK-NOT: test3.h
+// CHECK-NOT: . {{.*noline.h}}
 // CHECK: . {{.*test.h}}
 // CHECK: .. {{.*test2.h}}
 
-// RUN: %clang_cc1 -I%S -include Inputs/test3.h --show-includes -o /dev/null %s | \
+// RUN: %clang_cc1 -I%S -include Inputs/test3.h -isystem %S/Inputs/SystemHeaderPrefix \
+// RUN:     -E -H -sys-header-deps -o /dev/null %s 2> %t.stderr
+// RUN: FileCheck --check-prefix SYSHEADERS < %t.stderr %s
+
+// SYSHEADERS-NOT: test3.h
+// SYSHEADERS: . {{.*noline.h}}
+// SYSHEADERS: . {{.*test.h}}
+// SYSHEADERS: .. {{.*test2.h}}
+
+// RUN: %clang_cc1 -I%S -include Inputs/test3.h -isystem %S/Inputs/SystemHeaderPrefix \
+// RUN:     --show-includes -o /dev/null %s | \
 // RUN:     FileCheck --strict-whitespace --check-prefix=MS-STDOUT %s
 // MS-STDOUT-NOT: <command line>
+// MS-STDOUT-NOT: Note: including file: {{[^ ]*noline.h}}
 // MS-STDOUT: Note: including file: {{[^ ]*test3.h}}
 // MS-STDOUT: Note: including file: {{[^ ]*test.h}}
 // MS-STDOUT: Note: including file:  {{[^ ]*test2.h}}
 // MS-STDOUT-NOT: Note
 
-// RUN: %clang_cc1 -I%S -include Inputs/test3.h -E --show-includes -o /dev/null %s 2> %t.stderr
+// RUN: %clang_cc1 -I%S -include Inputs/test3.h -isystem %S/Inputs/SystemHeaderPrefix \
+// RUN:     -E --show-includes -o /dev/null %s 2> %t.stderr
 // RUN: FileCheck --strict-whitespace --check-prefix=MS-STDERR < %t.stderr %s
 // MS-STDERR-NOT: <command line>
+// MS-STDERR-NOT: Note: including file: {{[^ ]*noline.h}}
 // MS-STDERR: Note: including file: {{[^ ]*test3.h}}
 // MS-STDERR: Note: including file: {{[^ ]*test.h}}
 // MS-STDERR: Note: including file:  {{[^ ]*test2.h}}
 // MS-STDERR-NOT: Note
 
 // RUN: echo "fun:foo" > %t.blacklist
-// RUN: %clang_cc1 -I%S -fsanitize=address -fdepfile-entry=%t.blacklist --show-includes -o /dev/null %s | \
+// RUN: %clang_cc1 -I%S -isystem %S/Inputs/SystemHeaderPrefix \
+// RUN:     -fsanitize=address -fdepfile-entry=%t.blacklist \
+// RUN:     --show-includes -o /dev/null %s | \
 // RUN:     FileCheck --strict-whitespace --check-prefix=MS-BLACKLIST %s
 // MS-BLACKLIST: Note: including file: {{[^ ]*\.blacklist}}
+// MS-BLACKLIST-NOT: Note: including file: {{[^ ]*noline.h}}
 // MS-BLACKLIST: Note: including file: {{[^ ]*test.h}}
 // MS-BLACKLIST: Note: including file:  {{[^ ]*test2.h}}
 // MS-BLACKLIST-NOT: Note
 
+#include <noline.h>
 #include "Inputs/test.h"

clang/test/Preprocessor/headermap-rel2.c

 // RUN: rm -f %t.hmap
 // RUN: %hmaptool write %S/Inputs/headermap-rel2/project-headers.hmap.json %t.hmap
-// RUN: %clang_cc1 -v -fsyntax-only %s -iquote %t.hmap -isystem %S/Inputs/headermap-rel2/system/usr/include -I %S/Inputs/headermap-rel2 -H
-// RUN: %clang_cc1 -fsyntax-only %s -iquote %t.hmap -isystem %S/Inputs/headermap-rel2/system/usr/include -I %S/Inputs/headermap-rel2 -H 2> %t.out
+
+// RUN: %clang -fsyntax-only %s -iquote %t.hmap -isystem %S/Inputs/headermap-rel2/system/usr/include -I %S/Inputs/headermap-rel2 -H 2> %t.out
+// RUN: FileCheck %s -input-file %t.out
+
+// RUN: env CC_PRINT_HEADERS=1 %clang -fsyntax-only %s -iquote %t.hmap -isystem %S/Inputs/headermap-rel2/system/usr/include -I %S/Inputs/headermap-rel2 2> %t.out
 // RUN: FileCheck %s -input-file %t.out
 
 // CHECK: Product/someheader.h
 // CHECK: system/usr/include{{[/\\]+}}someheader.h
 // CHECK: system/usr/include{{[/\\]+}}someheader.h
 
 #include "someheader.h"
 #include <someheader.h>
 #include <someheader.h>