MIPS: allow o32 abi with 64bit CPU and 64 abi with 32bit triple

[wzssyqa]

Summary

In general, MIPS support ELF format like

ELF 32-bit LSB relocatable, MIPS, MIPS64 rel2 version 1 (SYSV)

and Linux's VDSO uses it.

Currently clang stop CMDs like

clang -march=mips64r2 -mabi=32

While it is not needed now, since the the backend support the combination now.

This patch also allows something like

clang --target=mipsel-linux-gnu -mabi=64

Since the triple can convert to right 64bit one automaticly.

[jrtc27]

Tests?

[wzssyqa]

In D146269#4201150, @jrtc27 wrote:

Tests?

Added.

[wzssyqa]

ping

[nickdesaulniers]

This came up in
https://lore.kernel.org/llvm/[e-mail]/
(follow up thread, FWIW: https://lore.kernel.org/llvm/[e-mail]/)

[nickdesaulniers]

In D146269#4239702, @wzssyqa wrote:

ping

@MaskRay is offline until Tuesday April 11.

[wzssyqa]

ping...

[MaskRay]

llvm/lib/Target/Mips/MipsSubtarget.cpp

107

[wzssyqa]

@MaskRay can you help to submit this patch?

[MaskRay]

clang/test/Driver/mips-cpu64abi32.c

2

Use /// for non-CHECK non-RUN comments.

6

-target is legacy. Use --target=.

Driver tests should not test code generation. Just check that %clang ... passes the right options to cc1.

10

Don't add ^//$ lines. Just use a blank line.

[wzssyqa]

@MaskRay ping?

[wzssyqa]

ping...

[MaskRay]

Is this the new GCC behavior?

clang -target mipsel-linux-gnu -mabi=64

Use --target=

[wzssyqa]

In D146269#4347514, @MaskRay wrote:

Is this the new GCC behavior?

Marking o32 objects with 64bit CPU is a long history gas behaviour, maybe appeared in 1990s, or even in the era of Irix.
I guess the reason is that to achive something like:

-mabi=32 -march=octeon

Octeon is a 64bit CPU.
Since no matter about the -march value, due to all of them are using o32 abi,
they can interlink.
And thus Linux kernel uses this behaviour.

clang -target mipsel-linux-gnu -mabi=64

Use --target=

Done

clang/lib/Basic/Targets/Mips.cpp

 }
 
 bool MipsTargetInfo::validateTarget(DiagnosticsEngine &Diags) const {
   // microMIPS64R6 backend was removed.
   if (getTriple().isMIPS64() && IsMicromips && (ABI == "n32" || ABI == "n64")) {
     Diags.Report(diag::err_target_unsupported_cpu_for_micromips) << CPU;
     return false;
   }
-  // FIXME: It's valid to use O32 on a 64-bit CPU but the backend can't handle
-  //        this yet. It's better to fail here than on the backend assertion.
-  if (processorSupportsGPR64() && ABI == "o32") {
-    Diags.Report(diag::err_target_unsupported_abi) << ABI << CPU;
-    return false;
-  }
 
   // 64-bit ABI's require 64-bit CPU's.
   if (!processorSupportsGPR64() && (ABI == "n32" || ABI == "n64")) {
     Diags.Report(diag::err_target_unsupported_abi) << ABI << CPU;
     return false;
   }
 
-  // FIXME: It's valid to use O32 on a mips64/mips64el triple but the backend
-  //        can't handle this yet. It's better to fail here than on the
-  //        backend assertion.
-  if (getTriple().isMIPS64() && ABI == "o32") {
-    Diags.Report(diag::err_target_unsupported_abi_for_triple)
-        << ABI << getTriple().str();
-    return false;
-  }
-
-  // FIXME: It's valid to use N32/N64 on a mips/mipsel triple but the backend
-  //        can't handle this yet. It's better to fail here than on the
-  //        backend assertion.
-  if (getTriple().isMIPS32() && (ABI == "n32" || ABI == "n64")) {
-    Diags.Report(diag::err_target_unsupported_abi_for_triple)
-        << ABI << getTriple().str();
-    return false;
-  }
-
   // -fpxx is valid only for the o32 ABI
   if (FPMode == FPXX && (ABI == "n32" || ABI == "n64")) {
     Diags.Report(diag::err_unsupported_abi_for_opt) << "-mfpxx" << "o32";
     return false;
   }
 
   // -mfp32 and n32/n64 ABIs are incompatible
   if (FPMode != FP64 && FPMode != FPXX && !IsSingleFloat &&

clang/test/Driver/mips-abi.c

 // Check passing Mips ABI options to the backend.
 //
 // REQUIRES: mips-registered-target
 //
 // RUN: %clang -target mips-linux-gnu -### -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS32R2-O32 %s
 // RUN: %clang -target mips64-linux-gnu -mips32r2 -mabi=32 -### -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS32R2-O32 %s
 // MIPS32R2-O32: "-target-cpu" "mips32r2"
 // MIPS32R2-O32: "-target-abi" "o32"
 //
-// FIXME: This is a valid combination of options but we reject it at the moment
-//        because the backend can't handle it.
-// RUN: not %clang -target mips-linux-gnu -c %s \
-// RUN:        -march=mips64r2 -mabi=32 2>&1 \
-// RUN:   | FileCheck -check-prefix=MIPS64R2-O32 %s
-// MIPS64R2-O32: error: ABI 'o32' is not supported on CPU 'mips64r2'
-//
 // RUN: %clang -target mips64-linux-gnu -### -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS64R2-N64 %s
 // RUN: %clang -target mips-img-linux-gnu -mips64r2 -### -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS64R2-N64 %s
 // RUN: %clang -target mips-mti-linux-gnu -mips64r2 -### -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS64R2-N64 %s
 // RUN: %clang -target mips-linux-gnu -mips64r2 -mabi=64 -### -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS64R2-N64 %s

clang/test/Driver/mips-cpu64abi32.c

+/// Check handling the CPU is 64bit while ABI is O32.
+/// when build for MIPS platforms.
+
+/// abi-n32
+// RUN: %clang -### -c %s --target=mips-linux-gnu -mabi=n32 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-ABI-N32 %s
+// CHECK-ABI-N32: "-target-abi" "n32"
+
+/// abi-64
+// RUN: %clang -### -c %s --target=mips-linux-gnu -mabi=64 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-ABI-64 %s
+// CHECK-ABI-64: "-target-abi" "n64"
+
+
+/// -march=mips3
+// RUN: %clang -### -c %s --target=mips-linux-gnu -march=mips3 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-MIPS-MIPS3 %s
+// CHECK-MIPS-MIPS3: "-target-cpu" "mips3" {{.*}} "-target-abi" "o32"
+
+/// -march=mips4
+// RUN: %clang -### -c %s --target=mips-linux-gnu -march=mips4 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-MIPS-MIPS4 %s
+// CHECK-MIPS-MIPS4: "-target-cpu" "mips4" {{.*}} "-target-abi" "o32"
+
+/// FIXME: MIPS V is not implemented yet.
+
+/// -march=mips64
+/// RUN: %clang -### -c %s --target=mips-linux-gnu -march=mips64 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-MIPS-MIPS64 %s
+// CHECK-MIPS-MIPS64: "-target-cpu" "mips64" {{.*}} "-target-abi" "o32"
+
+/// -march=mips64r2
+/// RUN: %clang -### -c %s --target=mips-linux-gnu -march=mips64r2 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-MIPS-MIPS64R2 %s
+// CHECK-MIPS-MIPS64R2: "-target-cpu" "mips64r2" {{.*}} "-target-abi" "o32"
+
+/// -march=mips64r6
+// RUN: %clang -### -c %s --target=mips-linux-gnu -march=mips64r6 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-MIPS-MIPS64R6 %s
+// CHECK-MIPS-MIPS64R6: "-target-cpu" "mips64r6" {{.*}} "-target-abi" "o32"
+
+
+/// mipsisa3
+// RUN: %clang -### -c %s --target=mips64-linux-gnu -march=mips3 -mabi=32 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-MIPS-MIPSISA3 %s
+// CHECK-MIPS-MIPSISA3: "-target-cpu" "mips3" {{.*}} "-target-abi" "o32"
+
+/// mipsisa4
+// RUN: %clang -### -c %s --target=mips64-linux-gnu -march=mips4 -mabi=32 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-MIPS-MIPSISA4 %s
+// CHECK-MIPS-MIPSISA4: "-target-cpu" "mips4" {{.*}} "-target-abi" "o32"
+
+/// FIXME: MIPS V is not implemented yet.
+
+/// mipsisa64
+// RUN: %clang -### -c %s --target=mips64-linux-gnu -march=mips64 -mabi=32 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-MIPS-MIPSISA64 %s
+// CHECK-MIPS-MIPSISA64: "-target-cpu" "mips64" {{.*}} "-target-abi" "o32"
+
+/// mipsisa64r2
+// RUN: %clang -### -c %s --target=mips64-linux-gnu -march=mips64r2 -mabi=32 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-MIPS-MIPSISA64R2 %s
+// CHECK-MIPS-MIPSISA64R2: "-target-cpu" "mips64r2" {{.*}} "-target-abi" "o32"
+
+/// mipsisa64r6
+// RUN: %clang -### -c %s --target=mips64-linux-gnu -march=mips64r6 -mabi=32 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-MIPS-MIPSISA64R6 %s
+// CHECK-MIPS-MIPSISA64R6: "-target-cpu" "mips64r6" {{.*}} "-target-abi" "o32"

llvm/lib/Target/Mips/MipsSubtarget.cpp

MipsSubtarget::MipsSubtarget(const Triple &TT, StringRef CPU, StringRef FS,
   }
 
   // Don't even attempt to generate code for MIPS-V. It has not
   // been tested and currently exists for the integrated assembler only.
   if (MipsArchVersion == Mips5)
     report_fatal_error("Code generation for MIPS-V is not implemented", false);
 
   // Check if Architecture and ABI are compatible.
-  assert(((!isGP64bit() && isABI_O32()) ||
-          (isGP64bit() && (isABI_N32() || isABI_N64()))) &&
+  assert(((!isGP64bit() && isABI_O32()) || isGP64bit()) &&
          "Invalid  Arch & ABI pair.");
 
   if (hasMSA() && !isFP64bit())
     report_fatal_error("MSA requires a 64-bit FPU register file (FR=1 mode). "
                        "See -mattr=+fp64.",
                        false);
 
   if (isFP64bit() && !hasMips64() && hasMips32() && !hasMips32r2())