[Driver] Support multi /guard: options

[rnk]

lgtm, thanks!

[pengfei]

Thanks @rnk !

[aeubanks]

this causes ./build/rel/bin/clang-cl /c /tmp/a.cc /Fo/tmp/a /guard:cf,nochecks to go from no warnings to

clang-cl: warning: argument unused during compilation: '/guard:cf,nochecks' [-Wunused-command-line-argument]

[pengfei]

Sorry for the noise, I guess I missed a A->claim() here. Updated.

[aeubanks]

if you add a test for the repro, relanding lgtm

[pengfei]

In D150645#4353408, @aeubanks wrote:

if you add a test for the repro, relanding lgtm

Thanks, done.

[pengfei]

Sorry for the back and forth! I just want to add a : after warning, but I forgot to amend it in the first reland..

[glandium]

In D150645#4351266, @aeubanks wrote:

this causes ./build/rel/bin/clang-cl /c /tmp/a.cc /Fo/tmp/a /guard:cf,nochecks to go from no warnings to

clang-cl: warning: argument unused during compilation: '/guard:cf,nochecks' [-Wunused-command-line-argument]

This affects 16.0.4

[pengfei]

In D150645#4379536, @glandium wrote:

In D150645#4351266, @aeubanks wrote:

this causes ./build/rel/bin/clang-cl /c /tmp/a.cc /Fo/tmp/a /guard:cf,nochecks to go from no warnings to

clang-cl: warning: argument unused during compilation: '/guard:cf,nochecks' [-Wunused-command-line-argument]

This affects 16.0.4

Sorry for making the trouble. I have made a backport request targeting 16.0.5: https://github.com/llvm/llvm-project/issues/62921

clang/lib/Driver/ToolChains/Clang.cpp

if (Args.hasArg(options::OPT__SLASH_kernel)) {
   if (!Args.hasArg(options::OPT_fdiagnostics_format_EQ)) {
     CmdArgs.push_back("-fdiagnostics-format");
     CmdArgs.push_back("msvc");
   }
 
   if (Args.hasArg(options::OPT__SLASH_kernel))
     CmdArgs.push_back("-fms-kernel");
 
-  if (Arg *A = Args.getLastArg(options::OPT__SLASH_guard)) {
+  for (const Arg *A : Args.filtered(options::OPT__SLASH_guard)) {
     StringRef GuardArgs = A->getValue();
     // The only valid options are "cf", "cf,nochecks", "cf-", "ehcont" and
     // "ehcont-".
     if (GuardArgs.equals_insensitive("cf")) {
       // Emit CFG instrumentation and the table of address-taken functions.
       CmdArgs.push_back("-cfguard");
     } else if (GuardArgs.equals_insensitive("cf,nochecks")) {
       // Emit only the table of address-taken functions.
       CmdArgs.push_back("-cfguard-no-checks");
     } else if (GuardArgs.equals_insensitive("ehcont")) {
       // Emit EH continuation table.
       CmdArgs.push_back("-ehcontguard");
     } else if (GuardArgs.equals_insensitive("cf-") ||
                GuardArgs.equals_insensitive("ehcont-")) {
       // Do nothing, but we might want to emit a security warning in future.
     } else {
       D.Diag(diag::err_drv_invalid_value) << A->getSpelling() << GuardArgs;
     }
+    A->claim();
   }
 }
 
 const char *Clang::getBaseInputName(const ArgList &Args,
                                     const InputInfo &Input) {
   return Args.MakeArgString(llvm::sys::path::filename(Input.getBaseInput()));
 }
 

clang/lib/Driver/ToolChains/MSVC.cpp

if (TC.getSanitizerArgs(Args).needsSharedRt() ||
             TC.getCompilerRT(Args, Lib)));
       }
     }
   }
 
   Args.AddAllArgValues(CmdArgs, options::OPT__SLASH_link);
 
   // Control Flow Guard checks
-  if (Arg *A = Args.getLastArg(options::OPT__SLASH_guard)) {
+  for (const Arg *A : Args.filtered(options::OPT__SLASH_guard)) {
     StringRef GuardArgs = A->getValue();
     if (GuardArgs.equals_insensitive("cf") ||
         GuardArgs.equals_insensitive("cf,nochecks")) {
       // MSVC doesn't yet support the "nochecks" modifier.
       CmdArgs.push_back("-guard:cf");
     } else if (GuardArgs.equals_insensitive("cf-")) {
       CmdArgs.push_back("-guard:cf-");
     } else if (GuardArgs.equals_insensitive("ehcont")) {

clang/test/Driver/cl-options.c

 
 // RUN: %clang_cl  -### -- %s 2>&1 | FileCheck -check-prefix=NOEHCONTGUARD %s
 // RUN: %clang_cl /guard:ehcont- -### -- %s 2>&1 | FileCheck -check-prefix=NOEHCONTGUARD %s
 // NOEHCONTGUARD-NOT: -ehcontguard
 
 // RUN: %clang_cl /guard:ehcont -### -- %s 2>&1 | FileCheck -check-prefix=EHCONTGUARD %s
 // EHCONTGUARD: -ehcontguard
 
+// RUN: %clang_cl /guard:cf /guard:ehcont -Wall -Wno-msvc-not-found -### -- %s 2>&1 | \
+// RUN:   FileCheck -check-prefix=BOTHGUARD %s --implicit-check-not=warning
+// BOTHGUARD: -cfguard
+// BOTHGUARD-SAME: -ehcontguard
+// BOTHGUARD: -guard:cf
+// BOTHGUARD-SAME: -guard:ehcont
+
 // RUN: %clang_cl /guard:foo -### -- %s 2>&1 | FileCheck -check-prefix=CFGUARDINVALID %s
 // CFGUARDINVALID: invalid value 'foo' in '/guard:'
 
 // Accept "core" clang options.
 // (/Zs is for syntax-only, -Werror makes it fail hard on unknown options)
 // RUN: %clang_cl \
 // RUN:     --driver-mode=cl \
 // RUN:     -fblocks \