[Driver] Reject -mcmodel=tiny on X86

clang/docs/ReleaseNotes.rst

@@ -374,6 +374,7 @@ Improvements to Clang's diagnostics
 
 
 - An error is now emitted when a ``musttail`` call is made to a function marked with the ``not_tail_called`` attribute. (#GH133509).
+- The ``-mcmodel=tiny`` option will now be diagnosed on all targets other than ARM or AArch64.
 
 Improvements to Clang's time-trace
 ----------------------------------

clang/lib/Driver/Driver.cpp

@@ -1755,6 +1755,18 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
         << TC.getTriple().str();
   }
 
+  // Throw diagnosis if mcmodel=tiny option is passed for targets other than ARM
+  // or AArch64.
+  if (Arg *A = UArgs->getLastArg(options::OPT_mcmodel_EQ)) {
+    StringRef ModelName = A->getValue();
+    if (ModelName == "tiny" &&
+        !(TC.getTriple().getArch() == llvm::Triple::aarch64 ||
+          TC.getTriple().getArch() == llvm::Triple::arm)) {
+      Diag(diag::err_drv_unsupported_option_argument_for_target)
+          << A->getSpelling() << ModelName << TC.getTriple().str();
+    }
+  }
+
   // A common user mistake is specifying a target of aarch64-none-eabi or
   // arm-none-elf whereas the correct names are aarch64-none-elf &
   // arm-none-eabi. Detect these cases and issue a warning.

clang/test/Driver/mcmodel.c

@@ -1,5 +1,5 @@
 // RUN: not %clang -### -c --target=i686 -mcmodel=medium %s 2>&1 | FileCheck --check-prefix=ERR-MEDIUM %s
-// RUN: %clang --target=x86_64 -### -c -mcmodel=tiny %s 2>&1 | FileCheck --check-prefix=TINY %s
+// RUN: not %clang --target=x86_64 -### -c -mcmodel=tiny %s 2>&1 | FileCheck --check-prefix=TINY %s
 // RUN: %clang --target=x86_64 -### -c -mcmodel=small %s 2>&1 | FileCheck --check-prefix=SMALL %s
 // RUN: %clang --target=x86_64 -### -S -mcmodel=kernel %s 2>&1 | FileCheck --check-prefix=KERNEL %s
 // RUN: %clang --target=x86_64 -### -c -mcmodel=medium %s 2>&1 | FileCheck --check-prefix=MEDIUM %s
@@ -44,3 +44,5 @@
 // ERR-AARCH64_32: error: unsupported argument 'small' to option '-mcmodel=' for target 'aarch64_32-unknown-linux'
 
 // ERR-LOONGARCH64-PLT-EXTREME: error: invalid argument '-mcmodel=extreme' not allowed with '-fplt'
+
+// CHECK: error: unsupported argument 'tiny' to option '-mcmodel=' for target '{{.*}}'