[clang] [Clang][Driver] report unsupported option error regardless of argument order (PR #116476)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-driver

Author: Reno Dakota (paparodeo)

<details>
<summary>Changes</summary>

Fixes: https://github.com/llvm/llvm-project/issues/116278

This change updates clang to report unsupported option errors regardless of the command line argument order.

When clang with a source file and without `-c` it will both compile and link. When an unsupported option is also part of the command line clang should generated an error. However, if the source file name comes before an object file, eg: `-lc`, the error is ignored.

```
$ clang --target=x86_64 -lc hello.c -mhtm
clang: error: unsupported option '-mhtm' for target 'x86_64'
$ echo $?
1
```

but if `-lc` comes after `hello.c` the error is dropped

```
$ clang --target=x86_64 hello.c -mhtm -lc
$ echo $?
0
```

after this change clang will report the error regardless of the command line argument order.

---
Full diff: https://github.com/llvm/llvm-project/pull/116476.diff


2 Files Affected:

- (modified) clang/lib/Driver/Driver.cpp (+6-7) 
- (modified) clang/test/Driver/unsupported-option.c (+10) 


``````````diff
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 93e85f7dffe35a..8e784a7b130ac3 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -4064,17 +4064,18 @@ void Driver::handleArguments(Compilation &C, DerivedArgList &Args,
     YcArg = YuArg = nullptr;
   }
 
-  unsigned LastPLSize = 0;
+  bool LinkOnly = phases::Link == FinalPhase && Inputs.size() > 0;
   for (auto &I : Inputs) {
     types::ID InputType = I.first;
     const Arg *InputArg = I.second;
 
     auto PL = types::getCompilationPhases(InputType);
-    LastPLSize = PL.size();
+
+    phases::ID InitialPhase = PL[0];
+    LinkOnly = LinkOnly && phases::Link == InitialPhase && PL.size() == 1;
 
     // If the first step comes after the final phase we are doing as part of
     // this compilation, warn the user about it.
-    phases::ID InitialPhase = PL[0];
     if (InitialPhase > FinalPhase) {
       if (InputArg->isClaimed())
         continue;
@@ -4129,10 +4130,8 @@ void Driver::handleArguments(Compilation &C, DerivedArgList &Args,
     }
   }
 
-  // If we are linking, claim any options which are obviously only used for
-  // compilation.
-  // FIXME: Understand why the last Phase List length is used here.
-  if (FinalPhase == phases::Link && LastPLSize == 1) {
+  // claim any options which are obviously only used for compilation.
+  if (LinkOnly) {
     Args.ClaimAllArgs(options::OPT_CompileOnly_Group);
     Args.ClaimAllArgs(options::OPT_cl_compile_Group);
   }
diff --git a/clang/test/Driver/unsupported-option.c b/clang/test/Driver/unsupported-option.c
index 6be531d9df7de9..af836cf0033741 100644
--- a/clang/test/Driver/unsupported-option.c
+++ b/clang/test/Driver/unsupported-option.c
@@ -17,3 +17,13 @@
 // RUN: not %clang -fprofile-sample-use=code.prof --target=powerpc-ibm-aix %s 2>&1 | \
 // RUN: FileCheck %s --check-prefix=AIX-PROFILE-SAMPLE
 // AIX-PROFILE-SAMPLE: error: unsupported option '-fprofile-sample-use=' for target
+
+// -mhtm is unsupported on x86_64. Test that using it in different command
+// line permutations generates an `unsupported option` error.
+// RUN: not %clang --target=x86_64 -### %s -mhtm 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=UNSUP_OPT
+// RUN: not %clang --target=x86_64 -### %s -mhtm -lc 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=UNSUP_OPT
+// RUN: not %clang --target=x86_64 -### -mhtm -lc %s 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=UNSUP_OPT
+// UNSUP_OPT: error: unsupported option

``````````

</details>


https://github.com/llvm/llvm-project/pull/116476