[clang][LoongArch] Add OHOS target

Add support for OHOS on LoongArch.

This patch is taken from part of the
https://gitee.com/openharmony/third_party_llvm-project/pulls/554,
the original author is @caiwei.

Co-authored-by: caiwei <[email protected]>

Author: Ami-zhang

clang/lib/Basic/Targets.cpp

@@ -741,16 +741,28 @@ std::unique_ptr<TargetInfo> AllocateTarget(const llvm::Triple &Triple,
   case llvm::Triple::loongarch32:
     switch (os) {
     case llvm::Triple::Linux:
-      return std::make_unique<LinuxTargetInfo<LoongArch32TargetInfo>>(Triple,
-                                                                      Opts);
+      switch (Triple.getEnvironment()) {
+      default:
+        return std::make_unique<LinuxTargetInfo<LoongArch32TargetInfo>>(Triple,
+                                                                        Opts);
+      case llvm::Triple::OpenHOS:
+        return std::make_unique<OHOSTargetInfo<LoongArch32TargetInfo>>(Triple,
+                                                                       Opts);
+      }
     default:
       return std::make_unique<LoongArch32TargetInfo>(Triple, Opts);
     }
   case llvm::Triple::loongarch64:
     switch (os) {
     case llvm::Triple::Linux:
-      return std::make_unique<LinuxTargetInfo<LoongArch64TargetInfo>>(Triple,
-                                                                      Opts);
+      switch (Triple.getEnvironment()) {
+      default:
+        return std::make_unique<LinuxTargetInfo<LoongArch64TargetInfo>>(Triple,
+                                                                        Opts);
+      case llvm::Triple::OpenHOS:
+        return std::make_unique<OHOSTargetInfo<LoongArch64TargetInfo>>(Triple,
+                                                                       Opts);
+      }
     case llvm::Triple::FreeBSD:
       return std::make_unique<FreeBSDTargetInfo<LoongArch64TargetInfo>>(Triple,
                                                                         Opts);

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -2458,7 +2458,8 @@ void Generic_GCC::GCCInstallationDetector::AddDefaultGCCPrefixes(
 
   static const char *const LoongArch64LibDirs[] = {"/lib64", "/lib"};
   static const char *const LoongArch64Triples[] = {
-      "loongarch64-linux-gnu", "loongarch64-unknown-linux-gnu"};
+      "loongarch64-linux-gnu", "loongarch64-unknown-linux-gnu",
+      "loongarch64-linux-ohos"};
 
   static const char *const M68kLibDirs[] = {"/lib"};
   static const char *const M68kTriples[] = {"m68k-unknown-linux-gnu",

clang/lib/Driver/ToolChains/OHOS.cpp

@@ -111,6 +111,8 @@ std::string OHOS::getMultiarchTriple(const llvm::Triple &T) const {
     return "x86_64-linux-ohos";
   case llvm::Triple::aarch64:
     return "aarch64-linux-ohos";
+  case llvm::Triple::loongarch64:
+    return "loongarch64-linux-ohos";
   }
   return T.str();
 }
@@ -368,7 +370,12 @@ void OHOS::addExtraOpts(llvm::opt::ArgStringList &CmdArgs) const {
   CmdArgs.push_back("-z");
   CmdArgs.push_back("relro");
   CmdArgs.push_back("-z");
-  CmdArgs.push_back("max-page-size=4096");
+  // LoongArch needs page size 16K
+  if (getArch() == llvm::Triple::loongarch64) {
+    CmdArgs.push_back("max-page-size=16384");
+  } else {
+    CmdArgs.push_back("max-page-size=4096");
+  }
   // .gnu.hash section is not compatible with the MIPS target
   if (getArch() != llvm::Triple::mipsel)
     CmdArgs.push_back("--hash-style=both");

clang/test/Preprocessor/ohos.c

@@ -3,13 +3,15 @@
 // RUN: %clang_cc1 -x c++ -E -dM -ffreestanding -triple=riscv64-linux-ohos < /dev/null | FileCheck %s -match-full-lines -check-prefix=RISCV64-OHOS-CXX
 // RUN: %clang_cc1 -x c++ -E -dM -ffreestanding -triple=mipsel-linux-ohos < /dev/null | FileCheck %s -match-full-lines -check-prefix=MIPSEL-OHOS-CXX
 // RUN: %clang_cc1 -x c++ -E -dM -ffreestanding -triple=x86_64-linux-ohos < /dev/null | FileCheck %s -match-full-lines -check-prefix=X86_64-OHOS-CXX
+// RUN: %clang_cc1 -x c++ -E -dM -ffreestanding -triple=loongarch64-linux-ohos < /dev/null | FileCheck %s -match-full-lines -check-prefix=LOONGARCH64-OHOS-CXX
 // RUN: %clang_cc1 -E -dM -ffreestanding -triple=arm-linux-ohos < /dev/null | FileCheck %s -check-prefix=OHOS-DEFS
 
 // ARM-OHOS-CXX: #define __STDCPP_DEFAULT_NEW_ALIGNMENT__ 8U
 // ARM64-OHOS-CXX: #define __STDCPP_DEFAULT_NEW_ALIGNMENT__ 16UL
 // RISCV64-OHOS-CXX: #define __STDCPP_DEFAULT_NEW_ALIGNMENT__ 16UL
 // MIPSEL-OHOS-CXX: #define __STDCPP_DEFAULT_NEW_ALIGNMENT__ 8U
 // X86_64-OHOS-CXX: #define __STDCPP_DEFAULT_NEW_ALIGNMENT__ 16UL
+// LOONGARCH64-OHOS-CXX: #define __STDCPP_DEFAULT_NEW_ALIGNMENT__ 16UL
 // OHOS-DEFS: __OHOS_FAMILY__
 // OHOS-DEFS: __OHOS__
 // OHOS-DEFS-NOT: __OHOS__