[clang] [Driver] Support -mcmodel= for LoongArch (PR #72514)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-driver

Author: Lu Weining (SixWeining)

<details>
<summary>Changes</summary>

7e42545 rejects unsupported mcmodel options, but small/medium/large should be supported models for LoongArch. In addition, to be compatible with gcc, mapping some of their values to clang's.

The mapping is:
```
     gcc          vs     clang
   "normal"            "small"
   "medium"            "medium"
   "extreme"           "large"
```

And AFAIK, gcc side doesn't plan to implement the "large" code model.

Link: https://gcc.gnu.org/onlinedocs/gcc/LoongArch-Options.html
Link: https://reviews.llvm.org/D150522

---
Full diff: https://github.com/llvm/llvm-project/pull/72514.diff


2 Files Affected:

- (modified) clang/lib/Driver/ToolChains/Clang.cpp (+10) 
- (modified) clang/test/Driver/mcmodel.c (+13) 


``````````diff
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index b462f5a44057d94..3a7e56f37259cb8 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5739,6 +5739,16 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       if (CM == "large" && RelocationModel != llvm::Reloc::Static)
         D.Diag(diag::err_drv_argument_only_allowed_with)
             << A->getAsString(Args) << "-fno-pic";
+    } else if (Triple.isLoongArch()) {
+      CM = llvm::StringSwitch<StringRef>(CM)
+               .Case("normal", "small")
+               .Case("extreme", "large")
+               .Default(CM);
+      if (CM == "large" &&
+          Args.hasFlag(options::OPT_fplt, options::OPT_fno_plt, false))
+        D.Diag(diag::err_drv_argument_not_allowed_with)
+            << A->getAsString(Args) << "-fplt";
+      Ok = CM == "small" || CM == "medium" || CM == "large";
     } else if (Triple.isPPC64() || Triple.isOSAIX()) {
       Ok = CM == "small" || CM == "medium" || CM == "large";
     } else if (Triple.isRISCV()) {
diff --git a/clang/test/Driver/mcmodel.c b/clang/test/Driver/mcmodel.c
index d8a41b0f5abd9aa..72be740216a81b3 100644
--- a/clang/test/Driver/mcmodel.c
+++ b/clang/test/Driver/mcmodel.c
@@ -15,6 +15,15 @@
 // RUN: not %clang -### -c --target=aarch64 -mcmodel=medium %s 2>&1 | FileCheck --check-prefix=ERR-MEDIUM %s
 // RUN: not %clang -### -c --target=aarch64 -mcmodel=kernel %s 2>&1 | FileCheck --check-prefix=ERR-KERNEL %s
 // RUN: not %clang --target=aarch64_32-linux -### -S -mcmodel=small %s 2>&1 | FileCheck --check-prefix=ERR-AARCH64_32 %s
+// RUN: %clang --target=loongarch64 -### -S -mcmodel=small %s 2>&1 | FileCheck --check-prefix=SMALL %s
+// RUN: %clang --target=loongarch64 -### -S -mcmodel=normal %s 2>&1 | FileCheck --check-prefix=SMALL %s
+// RUN: %clang --target=loongarch64 -### -S -mcmodel=medium %s 2>&1 | FileCheck --check-prefix=MEDIUM %s
+// RUN: %clang --target=loongarch64 -### -S -mcmodel=large %s 2>&1 | FileCheck --check-prefix=LARGE %s
+// RUN: %clang --target=loongarch64 -### -S -mcmodel=extreme %s 2>&1 | FileCheck --check-prefix=LARGE %s
+// RUN: not %clang --target=loongarch64 -### -S -mcmodel=tiny %s 2>&1 | FileCheck --check-prefix=ERR-TINY %s
+// RUN: not %clang --target=loongarch64 -### -S -mcmodel=kernel %s 2>&1 | FileCheck --check-prefix=ERR-KERNEL %s
+// RUN: not %clang --target=loongarch64 -### -S -mcmodel=large -fplt %s 2>&1 | FileCheck --check-prefix=ERR-LOONGARCH64-PLT-LARGE %s
+// RUN: not %clang --target=loongarch64 -### -S -mcmodel=extreme -fplt %s 2>&1 | FileCheck --check-prefix=ERR-LOONGARCH64-PLT-EXTREME %s
 
 // TINY: "-mcmodel=tiny"
 // SMALL: "-mcmodel=small"
@@ -25,9 +34,13 @@
 
 // INVALID: error: unsupported argument 'lager' to option '-mcmodel=' for target '{{.*}}'
 
+// ERR-TINY: error: unsupported argument 'tiny' to option '-mcmodel=' for target '{{.*}}'
 // ERR-MEDIUM: error: unsupported argument 'medium' to option '-mcmodel=' for target '{{.*}}'
 // ERR-KERNEL: error: unsupported argument 'kernel' to option '-mcmodel=' for target '{{.*}}'
 // ERR-LARGE:  error: unsupported argument 'large' to option '-mcmodel=' for target '{{.*}}'
 
 // AARCH64-PIC-LARGE: error: invalid argument '-mcmodel=large' only allowed with '-fno-pic'
 // ERR-AARCH64_32: error: unsupported argument 'small' to option '-mcmodel=' for target 'aarch64_32-unknown-linux'
+
+// ERR-LOONGARCH64-PLT-LARGE: error: invalid argument '-mcmodel=large' not allowed with '-fplt'
+// ERR-LOONGARCH64-PLT-EXTREME: error: invalid argument '-mcmodel=extreme' not allowed with '-fplt'

``````````

</details>


https://github.com/llvm/llvm-project/pull/72514