Enable zbb for riscv android

[enh]

thanks!

[jrtc27]

Go fix the default ISA string for Android, don't hack it here.

[pirama]

In D152729#4414617, @jrtc27 wrote:

Go fix the default ISA string for Android, don't hack it here.

If this is not the right way to change the default, can you point us to the right place?

[jrtc27]

In D152729#4414709, @pirama wrote:

In D152729#4414617, @jrtc27 wrote:

Go fix the default ISA string for Android, don't hack it here.

If this is not the right way to change the default, can you point us to the right place?

Where the defaults for all other OSes are set (since none of those default to plain RV64I): https://github.com/llvm/llvm-project/blob/d3074f16a6f6b3447bf728d8a6d19f35f02179db/clang/lib/Driver/ToolChains/Arch/RISCV.cpp#L238

[hiraditya]

Addressed @jrtc27's comment

[jrtc27]

clang/lib/Driver/ToolChains/Arch/RISCV.cpp

299–300

What about this case? Though why this doesn't also check UnknownOS and do something sensible for plain lp64 I don't know... I have a funny feeling I even commented on some riscv-toolchain-conventions issue about this kind of craziness where passing seemingly no-op options (ones that match the default) have knock-on effects.

314–320

[jrtc27]

clang/test/Driver/riscv-features.c

3

You should be checking DEFAULT too to check +relax vs -relax

8

Put this with the other feature lines

[enh]

clang/lib/Driver/ToolChains/Arch/RISCV.cpp

300

(stray tab)

[hiraditya]

clang/lib/Driver/ToolChains/Arch/RISCV.cpp

300

it is just the way phabricator shows whitespace changes. I verified in the uploaded patch.

[hiraditya]

@jrtc27 do you have any pending comments?

[jrtc27]

In D152729#4417707, @hiraditya wrote:

@jrtc27 do you have any pending comments?

No objections now, thanks

[hiraditya]

No objections now, thanks

sure. thanks for pointing to the right code.

clang/lib/Driver/ToolChains/Arch/RISCV.cpp

StringRef riscv::getRISCVArch(const llvm::opt::ArgList &Args,
   // lp64 | lp64f | lp64d -> rv64imafdc
   if (const Arg *A = Args.getLastArg(options::OPT_mabi_EQ)) {
     StringRef MABI = A->getValue();
 
     if (MABI.equals_insensitive("ilp32e"))
       return "rv32e";
     else if (MABI.starts_with_insensitive("ilp32"))
       return "rv32imafdc";
-    else if (MABI.starts_with_insensitive("lp64"))
+    else if (MABI.starts_with_insensitive("lp64")) {
+      if (Triple.isAndroid())
+        return "rv64imafdc_zbb";
+
       return "rv64imafdc";
     }
+  }
 
   // 4. Choose a default based on the triple
   //
   // We deviate from GCC's defaults here:
   // - On `riscv{XLEN}-unknown-elf` we default to `rv{XLEN}imac`
   // - On all other OSs we use `rv{XLEN}imafdc` (equivalent to `rv{XLEN}gc`)
   if (Triple.isRISCV32()) {
     if (Triple.getOS() == llvm::Triple::UnknownOS)
       return "rv32imac";
     else
       return "rv32imafdc";
   } else {
     if (Triple.getOS() == llvm::Triple::UnknownOS)
       return "rv64imac";
+    else if (Triple.isAndroid())
+      return "rv64imafdc_zbb";
     else
       return "rv64imafdc";
   }
 }
 
 std::string riscv::getRISCVTargetCPU(const llvm::opt::ArgList &Args,
                                      const llvm::Triple &Triple) {
   std::string CPU;
   // If we have -mcpu, use that.
   if (const Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
     CPU = A->getValue();

clang/test/Driver/riscv-features.c

 // RUN: %clang --target=riscv32-unknown-elf -### %s -fsyntax-only 2>&1 | FileCheck %s
 // RUN: %clang --target=riscv64-unknown-elf -### %s -fsyntax-only 2>&1 | FileCheck %s
+// RUN: %clang --target=riscv64-linux-android -### %s -fsyntax-only 2>&1 | FileCheck %s -check-prefixes=ANDROID,DEFAULT
+// RUN: %clang -mabi=lp64d --target=riscv64-linux-android -### %s -fsyntax-only 2>&1 | FileCheck %s -check-prefixes=ANDROID,DEFAULT
 
 // CHECK: fno-signed-char
 
 // RUN: %clang --target=riscv32-unknown-elf -### %s 2>&1 | FileCheck %s -check-prefix=DEFAULT
 
 // RUN: %clang --target=riscv32-unknown-elf -### %s -mrelax 2>&1 | FileCheck %s -check-prefix=RELAX
 // RUN: %clang --target=riscv32-unknown-elf -### %s -mno-relax 2>&1 | FileCheck %s -check-prefix=NO-RELAX
 
+// ANDROID: "-target-feature" "+zbb"
 // RELAX: "-target-feature" "+relax"
 // NO-RELAX: "-target-feature" "-relax"
 // DEFAULT: "-target-feature" "+relax"
 // DEFAULT-NOT: "-target-feature" "-relax"
 
 // RUN: %clang --target=riscv32-unknown-elf -### %s -msave-restore 2>&1 | FileCheck %s -check-prefix=SAVE-RESTORE
 // RUN: %clang --target=riscv32-unknown-elf -### %s -mno-save-restore 2>&1 | FileCheck %s -check-prefix=NO-SAVE-RESTORE