[RISCV] Fix the include search path order between sysroot and resource folder

[kito-cheng]

Summary

Resource folder[1] should include before sysroot[2] in general (Linux clang
toolchain, BareMetal clang toolchain, and GCC using that order), and that
prevent sysroot's header file override resource folder's one, this change is
reference from BareMetal::[e-mail][3].

And also fix the behavior of -nobuiltininc.

[1] Include path from resource folder is something like this: <toolchain-path>/lib/clang/13.0.0/include/
[2] Include path from sysroot is something like this: <toolchain-path>/riscv32-unknown-elf/include
[3] https://github.com/llvm/llvm-project/blob/llvmorg-13.0.1/clang/lib/Driver/ToolChains/BareMetal.cpp#L193

[asb]

Thanks Kito. This LGTM, but I'd appreciate someone else reviewing and approving as well.

[abidh]

In D119837#3326179, @asb wrote:

Thanks Kito. This LGTM, but I'd appreciate someone else reviewing and approving as well.

Looks ok to me too.

[kito-cheng]

Revert due to windows build regression fail: https://lab.llvm.org/buildbot/#/builders/216/builds/195

[kito-cheng]

Recommit with windows path fix: https://reviews.llvm.org/rG47b1fa5fc48821eefefd157ed4af2f2cf3bacef4

clang/lib/Driver/ToolChains/RISCVToolchain.cpp

void RISCVToolChain::addClangTargetOptions(
   CC1Args.push_back("-nostdsysteminc");
 }
 
 void RISCVToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
                                                ArgStringList &CC1Args) const {
   if (DriverArgs.hasArg(options::OPT_nostdinc))
     return;
 
+  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
+    SmallString<128> Dir(getDriver().ResourceDir);
+    llvm::sys::path::append(Dir, "include");
+    addSystemInclude(DriverArgs, CC1Args, Dir.str());
+  }
+
   if (!DriverArgs.hasArg(options::OPT_nostdlibinc)) {
     SmallString<128> Dir(computeSysRoot());
     llvm::sys::path::append(Dir, "include");
     addSystemInclude(DriverArgs, CC1Args, Dir.str());
   }
 }
 
 void RISCVToolChain::addLibStdCxxIncludePaths(

clang/test/Driver/riscv32-toolchain.c

 // RUN:   --gcc-toolchain=%S/Inputs/multilib_riscv_elf_sdk \
 // RUN:   -target riscv32-unknown-elf --rtlib=compiler-rt 2>&1 \
 // RUN:   | FileCheck -check-prefix=C-RV32-RTLIB-COMPILERRT-ILP32 %s
 // C-RV32-RTLIB-COMPILERRT-ILP32: "{{.*}}crt0.o"
 // C-RV32-RTLIB-COMPILERRT-ILP32: "{{.*}}clang_rt.crtbegin-riscv32.o"
 // C-RV32-RTLIB-COMPILERRT-ILP32: "--start-group" "-lc" "-lgloss" "--end-group" "{{.*}}libclang_rt.builtins-riscv32.a"
 // C-RV32-RTLIB-COMPILERRT-ILP32: "{{.*}}clang_rt.crtend-riscv32.o"
 
+// RUN: %clang %s -### -no-canonical-prefixes -target riscv32 \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_riscv32_tree \
+// RUN:   -resource-dir=%s/Inputs/resource_dir 2>&1 \
+// RUN:   | FileCheck -check-prefix=RESOURCE-INC %s
+// RESOURCE-INC: "-internal-isystem" "{{.*}}/Inputs/resource_dir/include"
+// RESOURCE-INC: "-internal-isystem" "{{.*}}/basic_riscv32_tree/{{.*}}/riscv32-unknown-elf/include"
+
+// RUN: %clang %s -### -no-canonical-prefixes -target riscv32 \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_riscv32_tree \
+// RUN:   -resource-dir=%s/Inputs/resource_dir -nobuiltininc 2>&1 \
+// RUN:   | FileCheck -check-prefix=NO-RESOURCE-INC %s
+// NO-RESOURCE-INC-NOT: "-internal-isystem" "{{.*}}/Inputs/resource_dir/include"
+// NO-RESOURCE-INC: "-internal-isystem" "{{.*}}/basic_riscv32_tree/{{.*}}/riscv32-unknown-elf/include"
+
 // RUN: %clang -target riscv32 %s -emit-llvm -S -o - | FileCheck %s
 
 typedef __builtin_va_list va_list;
 typedef __SIZE_TYPE__ size_t;
 typedef __PTRDIFF_TYPE__ ptrdiff_t;
 typedef __WCHAR_TYPE__ wchar_t;
 typedef __WINT_TYPE__ wint_t;
 

clang/test/Driver/riscv64-toolchain.c

 // RUN:   --gcc-toolchain=%S/Inputs/multilib_riscv_elf_sdk \
 // RUN:   -target riscv64-unknown-elf --rtlib=compiler-rt 2>&1 \
 // RUN:   | FileCheck -check-prefix=C-RV64-RTLIB-COMPILERRT-LP64 %s
 // C-RV64-RTLIB-COMPILERRT-LP64: "{{.*}}crt0.o"
 // C-RV64-RTLIB-COMPILERRT-LP64: "{{.*}}clang_rt.crtbegin-riscv64.o"
 // C-RV64-RTLIB-COMPILERRT-LP64: "--start-group" "-lc" "-lgloss" "--end-group" "{{.*}}libclang_rt.builtins-riscv64.a"
 // C-RV64-RTLIB-COMPILERRT-LP64: "{{.*}}clang_rt.crtend-riscv64.o"
 
+// RUN: %clang %s -### -no-canonical-prefixes -target riscv64 \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_riscv64_tree \
+// RUN:   -resource-dir=%s/Inputs/resource_dir 2>&1 \
+// RUN:   | FileCheck -check-prefix=RESOURCE-INC %s
+// RESOURCE-INC: "-internal-isystem" "{{.*}}/Inputs/resource_dir/include"
+// RESOURCE-INC: "-internal-isystem" "{{.*}}/basic_riscv64_tree/{{.*}}/riscv64-unknown-elf/include"
+
+// RUN: %clang %s -### -no-canonical-prefixes -target riscv64 \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_riscv64_tree \
+// RUN:   -resource-dir=%s/Inputs/resource_dir -nobuiltininc 2>&1 \
+// RUN:   | FileCheck -check-prefix=NO-RESOURCE-INC %s
+// NO-RESOURCE-INC-NOT: "-internal-isystem" "{{.*}}Inputs/resource_dir/include"
+// NO-RESOURCE-INC: "-internal-isystem" "{{.*}}/basic_riscv64_tree/{{.*}}/riscv64-unknown-elf/include"
+
 // RUN: %clang -target riscv64 %s -emit-llvm -S -o - | FileCheck %s
 
 typedef __builtin_va_list va_list;
 typedef __SIZE_TYPE__ size_t;
 typedef __PTRDIFF_TYPE__ ptrdiff_t;
 typedef __WCHAR_TYPE__ wchar_t;
 typedef __WINT_TYPE__ wint_t;