[AIX] Generate large code model relocations when mcmodel=medium on AIX

[anjankgk]

Summary

This patch makes the changes in the driver that converts the medium code model to large.

[hubert.reinterpretcast]

LGTM with minor nit; thanks.

clang/lib/Driver/ToolChains/Clang.cpp

5144

Add braces to the else block when adding braces to the if block: The coding guidelines have been updated for some time to discourage mixed bracing on if/else chains (see example

// Use braces for the `if` block to keep it uniform with the else block.

).

[anjankgk]

Added braces for else-block.

[anjankgk]

In D106371#2892186, @hubert.reinterpretcast wrote:

LGTM with minor nit; thanks.

Done. @hubert.reinterpretcast Hubert, could you pls help me commit this?
Thanks!

[anjankgk]

Anjan Kumar Guttahalli Krishna <[e-mail]>

Thank you!

[hubert.reinterpretcast]

In D106371#2894736, @anjankgk wrote:

Anjan Kumar Guttahalli Krishna <[e-mail]>

Thank you!

I running a build with this now -- I'll check its status in the morning.

[xgupta]

In D106371#2894736, @anjankgk wrote:

Anjan Kumar Guttahalli Krishna <[e-mail]>

Thank you!

Seems you are contributing with an official mail, I think you can ask for commit access, if you want to continue contributing, bar is quite low in LLVM community.
May follow:
https://llvm.org/docs/DeveloperPolicy.html#obtaining-commit-access

[anjankgk]

Since Hubert is busy, I have requested Shimin to commit this in.
Thanks Shimin!

[MaskRay]

clang/test/Driver/mcmodel.c

15

Is it intentional that -mcmodel=medium is changed to large for 32-bit systems? Is this AIX specific?

In GCC, I believe in general only 64-bit architectures support -mcmodel= with some exceptions like nds32.

clang/lib/Driver/ToolChains/Clang.cpp

#endif
   TC.addClangTargetOptions(Args, CmdArgs, JA.getOffloadingDeviceKind());
 
   // FIXME: Handle -mtune=.
   (void)Args.hasArg(options::OPT_mtune_EQ);
 
   if (Arg *A = Args.getLastArg(options::OPT_mcmodel_EQ)) {
     StringRef CM = A->getValue();
     if (CM == "small" || CM == "kernel" || CM == "medium" || CM == "large" ||
-        CM == "tiny")
-      A->render(Args, CmdArgs);
+        CM == "tiny") {
+      if (Triple.isOSAIX() && CM == "medium")
+        CmdArgs.push_back("-mcmodel=large");
       else
+        A->render(Args, CmdArgs);
+    } else {
       D.Diag(diag::err_drv_invalid_argument_to_option)
           << CM << A->getOption().getName();
     }
+  }
 
   if (Arg *A = Args.getLastArg(options::OPT_mtls_size_EQ)) {
     StringRef Value = A->getValue();
     unsigned TLSSize = 0;
     Value.getAsInteger(10, TLSSize);
     if (!Triple.isAArch64() || !Triple.isOSBinFormatELF())
       D.Diag(diag::err_drv_unsupported_opt_for_target)
           << A->getOption().getName() << TripleStr;

clang/test/Driver/mcmodel.c

 // RUN: %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
 // RUN: %clang -target x86_64 -### -S -mcmodel=large %s 2>&1 | FileCheck --check-prefix=LARGE %s
+// RUN: %clang -target powerpc-unknown-aix -### -S -mcmodel=medium %s 2> %t.log
+// RUN: FileCheck --check-prefix=AIX-MCMEDIUM-OVERRIDE %s < %t.log
 // RUN: not %clang -c -mcmodel=lager %s 2>&1 | FileCheck --check-prefix=INVALID %s
 
 // TINY: "-mcmodel=tiny"
 // SMALL: "-mcmodel=small"
 // KERNEL: "-mcmodel=kernel"
 // MEDIUM: "-mcmodel=medium"
 // LARGE: "-mcmodel=large"
+// AIX-MCMEDIUM-OVERRIDE: "-mcmodel=large"
 
 // INVALID: error: invalid argument 'lager' to -mcmodel=