[Driver] Support -mcmodel= for LoongArch #72514

SixWeining · 2023-11-16T14:16:54Z

7e42545 rejects unsupported mcmodel options, but normal/medium/extreme should be supported models for LoongArch according to gcc document.

The mappings among gcc, clang driver, clang cc1 and LLVM (i.e. llc --code-model=) are:

gcc	clang driver	clang cc1	LLVM
normal	normal	small	small
medium	medium	medium	medium
extreme	extreme	large	large

Link: https://reviews.llvm.org/D150522

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[1] vs clang[2] "normal" "small" "medium" "medium" "extreme" "large" And AFAIK, gcc side doesn't plan to implement the "large" code model. [1]: https://gcc.gnu.org/onlinedocs/gcc/LoongArch-Options.html [2]: https://reviews.llvm.org/D150522

llvmbot · 2023-11-16T14:17:27Z

@llvm/pr-subscribers-clang-driver

Author: Lu Weining (SixWeining)

Changes

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 --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'

llvmbot · 2023-11-16T14:17:27Z

@llvm/pr-subscribers-clang

Author: Lu Weining (SixWeining)

Changes

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 --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'

SixWeining · 2023-11-16T14:18:05Z

cc @xen0n @xry111

xry111 · 2023-11-16T16:10:07Z

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

Why did we distinguish "large" and "extreme" in the first place? If we don't need a different "large" code model then I guess we should make it an alias of "extreme" for GCC too.

SixWeining · 2023-11-17T01:35:49Z

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

Why did we distinguish "large" and "extreme" in the first place? If we don't need a different "large" code model then I guess we should make it an alias of "extreme" for GCC too.

@ChenghuaXu @chenglulu326 What do you think?

MaskRay · 2023-11-22T18:40:32Z

clang/lib/Driver/ToolChains/Clang.cpp

+               .Case("extreme", "large")
+               .Default(CM);
+      if (CM == "large" &&
+          Args.hasFlag(options::OPT_fplt, options::OPT_fno_plt, false))


I consider -fno-pic/-fpic a more fundamental difference than -mcmodel=, so I place the aarch64 compatibility check in this large if condition.

-mcmodel= is a more fundamental difference than -fplt, so the -fplt compatibility check should probably belong to -fplt. You can move

if (Args.hasFlag(options::OPT_fno_plt, options::OPT_fplt, false)) {

below CodeModel check and add the diagnostic there.

nvm. this is fine

MaskRay · 2023-11-22T18:43:10Z

clang/lib/Driver/ToolChains/Clang.cpp

+               .Case("extreme", "large")
+               .Default(CM);
+      if (CM == "large" &&
+          Args.hasFlag(options::OPT_fplt, options::OPT_fno_plt, false))


hasFlagNoClaim is slightly better

MaskRay · 2023-11-22T18:44:01Z

gcc.gnu.org/onlinedocs/gcc/LoongArch-Options.html says

‘large (Not implemented yet)’
‘extreme’
This mode does not limit the size of the code segment and data segment. The -mcmodel=extreme option is incompatible with -fplt, and it requires -mexplicit-relocs=always.

Is there a psABI defining 'extreme' or 'large'?

MaskRay · 2023-11-22T18:45:45Z

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


If -mcmodel=normal is canonical, we probably should not add Clang-specific alias small. Reject small.

SixWeining · 2023-11-24T04:56:24Z

gcc.gnu.org/onlinedocs/gcc/LoongArch-Options.html says

‘large (Not implemented yet)’ ‘extreme’ This mode does not limit the size of the code segment and data segment. The -mcmodel=extreme option is incompatible with -fplt, and it requires -mexplicit-relocs=always.

Is there a psABI defining 'extreme' or 'large'?

Currently there is no definition in psABI except in gcc doc: https://gcc.gnu.org/onlinedocs/gcc/LoongArch-Options.html. Maybe we can define them in next psABI version.

zjiaz · 2023-11-30T03:37:04Z

FWIW, mcmodel=medium option is used in chromium's build config file, and now chromium's llvm toolchain has been affected by this issue:

clang++: error: unsupported argument 'medium' to option '-mcmodel=' for target 'loongarch64-unknown-linux-gnu'

wangleiat

LGTM

MaskRay · 2023-12-01T18:02:38Z

LGTM

7e42545 rejects unsupported mcmodel options, but normal/medium/extreme should be supported models for LoongArch according to [gcc document](https://gcc.gnu.org/onlinedocs/gcc/LoongArch-Options.html). The mappings among `gcc`, `clang driver`, `clang cc1` and `LLVM (i.e. llc --code-model=)` are: | gcc | clang driver | clang cc1 | LLVM | | ------------- | ------------------ | ----------------- | -------------- | | normal | normal | small | small | | medium | medium | medium | medium | | extreme | extreme | large | large | (cherry picked from commit 1296d20) Change-Id: I45837ad55bfedaf33a7fc9bc40a654a37694ced0

R_LARCH_DELETE and R_LARCH_CFA are marked as reserved in psABI v2.20[1]. This patch copys the changes from an upstream commit. The original patch link is as below[2]. [1]https://github.com/loongson/la-abi-specs/releases/download/v2.20/la-abi-v2.20.pdf [2]llvm#72514 (cherry picked from commit 2cdfabe) Change-Id: I6c01a03d46d7f1b622258403a8863e33ddf8d36d

SixWeining requested a review from MaskRay November 16, 2023 14:17

llvmbot added clang Clang issues not falling into any other category clang:driver 'clang' and 'clang++' user-facing binaries. Not 'clang-cl' labels Nov 16, 2023

SixWeining requested review from heiher and wangleiat November 16, 2023 14:17

MaskRay reviewed Nov 22, 2023

View reviewed changes

Reject small and large. Only accept normal, medium and extreme

240149f

wangleiat approved these changes Nov 30, 2023

View reviewed changes

SixWeining merged commit 1296d20 into llvm:main Nov 30, 2023

xen0n mentioned this pull request Nov 30, 2023

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SixWeining deleted the driver-mcmodel branch December 1, 2023 01:38

yxd-ym mentioned this pull request Aug 23, 2024

loongarch: use medium code model for zig loongarch64 binary ziglang/zig#21153

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[Driver] Support -mcmodel= for LoongArch #72514

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