clang-cl: Warn when a /TC or /TP argument is unused

[hans]

test/Driver/cl-inputs.c

49

Can't you just att this to the TPlib checks above? (And similarly for /TC below.)

[• ehsan]

test/Driver/cl-inputs.c

49

No, note the %s in the tests above. In those tests, /TC and /TP are used on cl-inputs.c.

[hans]

test/Driver/cl-inputs.c

49

Ah, I didn't notice the %s before.

It still seems that these two tests are very similar. How about dropping the %s above and merging them?

[• ehsan]

test/Driver/cl-inputs.c

49

The first test does ensure that we generate one command for the compilation of cl-inputs.c and the second test doesn't. I don't think they are quite identical. But if you think that distinction isn't worth having two separate tests for, I'd be happy to merge them.

[hans]

test/Driver/cl-inputs.c

49

Yeah, I don't think that distinction is important.

The way I see it, the important part of the first test is that cl-test.lib doesn't get "compiled".

[• ehsan]

Addressed the comments!

[hans]

lgtm

[• ehsan]

Closed by commit rL217710 (authored by @ehsan).

lib/Driver/Driver.cpp

void Driver::BuildInputs(const ToolChain &TC, DerivedArgList &Args,
                          InputList &Inputs) const {
   // Track the current user specified (-x) input. We also explicitly track the
   // argument used to set the type; we only want to claim the type when we
   // actually use it, so we warn about unused -x arguments.
   types::ID InputType = types::TY_Nothing;
   Arg *InputTypeArg = nullptr;
 
   // The last /TC or /TP option sets the input type to C or C++ globally.
-  if (Arg *TCTP = Args.getLastArg(options::OPT__SLASH_TC,
+  if (Arg *TCTP = Args.getLastArgNoClaim(options::OPT__SLASH_TC,
                                          options::OPT__SLASH_TP)) {
     InputTypeArg = TCTP;
     InputType = TCTP->getOption().matches(options::OPT__SLASH_TC)
         ? types::TY_C : types::TY_CXX;
 
     arg_iterator it = Args.filtered_begin(options::OPT__SLASH_TC,
                                           options::OPT__SLASH_TP);
     const arg_iterator ie = Args.filtered_end();
     Arg *Previous = *it++;

test/Driver/cl-inputs.c

 // Tp-NOT: note
 
 // RUN: %clang_cl /TP /TC /TP -### -- %s 2>&1 | FileCheck -check-prefix=WARN %s
 // WARN: warning: overriding '/TP' option with '/TC'
 // WARN: warning: overriding '/TC' option with '/TP'
 // WARN: note: The last /TC or /TP option takes precedence over earlier instances
 // WARN-NOT: note
 
-// RUN: env LIB=%S/Inputs/cl-libs %clang_cl /c /TP cl-test.lib %s -### 2>&1 | FileCheck -check-prefix=TPlib %s
+// RUN: env LIB=%S/Inputs/cl-libs %clang_cl /c /TP cl-test.lib -### 2>&1 | FileCheck -check-prefix=TPlib %s
 // TPlib: warning: cl-test.lib: 'linker' input unused
+// TPlib: warning: argument unused during compilation: '/TP'
 // TPlib-NOT: cl-test.lib
 
-// RUN: env LIB=%S/Inputs/cl-libs %clang_cl /c /TC cl-test.lib %s -### 2>&1 | FileCheck -check-prefix=TClib %s
+// RUN: env LIB=%S/Inputs/cl-libs %clang_cl /c /TC cl-test.lib -### 2>&1 | FileCheck -check-prefix=TClib %s
 // TClib: warning: cl-test.lib: 'linker' input unused
+// TClib: warning: argument unused during compilation: '/TC'
 // TClib-NOT: cl-test.lib
 
 // RUN: not %clang_cl - 2>&1 | FileCheck -check-prefix=STDIN %s
 // STDIN: error: use /Tc or /Tp
 
 // RUN: %clang_cl -### /Tc - 2>&1 | FileCheck -check-prefix=STDINTc %s
 // STDINTc: "-x" "c"
 
 // RUN: env LIB=%S/Inputs/cl-libs %clang_cl -### -- %s cl-test.lib 2>&1 | FileCheck -check-prefix=LIBINPUT %s
 // LIBINPUT: link.exe"
 // LIBINPUT: "cl-test.lib"
 
 // RUN: env LIB=%S/Inputs/cl-libs %clang_cl -### -- %s cl-test2.lib 2>&1 | FileCheck -check-prefix=LIBINPUT2 %s
 // LIBINPUT2: error: no such file or directory: 'cl-test2.lib'
 // LIBINPUT2: link.exe"
 // LIBINPUT2-NOT: "cl-test2.lib"
 
 void f();