[clang] [RISCV] Emit arch string macro to facilitate ASM programming (PR #85063)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang

@llvm/pr-subscribers-backend-risc-v

Author: Nemanja Ivanovic (nemanjai)

<details>
<summary>Changes</summary>

In order to make assembly programming more convenient, emit macro __riscv_cmdline_arch_string that will be defined to the arch string based on the command line arguments. This string may differ from the actual string that is added to the object or assembly file. This provides a convenient mechanism for the programmer to add the .attribute directive into pre-processed asm files.

Example file.S:
.attribute 5, __riscv_cmdline_arch_string

---
Full diff: https://github.com/llvm/llvm-project/pull/85063.diff


2 Files Affected:

- (modified) clang/lib/Basic/Targets/RISCV.cpp (+2) 
- (modified) clang/test/Preprocessor/riscv-target-features.c (+8) 


``````````diff
diff --git a/clang/lib/Basic/Targets/RISCV.cpp b/clang/lib/Basic/Targets/RISCV.cpp
index a6d4af2b88111a..718d94f2d2621e 100644
--- a/clang/lib/Basic/Targets/RISCV.cpp
+++ b/clang/lib/Basic/Targets/RISCV.cpp
@@ -139,6 +139,7 @@ void RISCVTargetInfo::getTargetDefines(const LangOptions &Opts,
   unsigned MinVLen = ISAInfo->getMinVLen();
   unsigned MaxELen = ISAInfo->getMaxELen();
   unsigned MaxELenFp = ISAInfo->getMaxELenFp();
+  std::string ArchString = "\"" + ISAInfo->toString() + "\"";
   if (CodeModel == "default")
     CodeModel = "small";
 
@@ -222,6 +223,7 @@ void RISCVTargetInfo::getTargetDefines(const LangOptions &Opts,
     else
       Builder.defineMacro("__riscv_32e");
   }
+  Builder.defineMacro("__riscv_cmdline_arch_string", ArchString);
 }
 
 static constexpr Builtin::Info BuiltinInfo[] = {
diff --git a/clang/test/Preprocessor/riscv-target-features.c b/clang/test/Preprocessor/riscv-target-features.c
index 1a15be1c6e4dc1..6023abe2665c2a 100644
--- a/clang/test/Preprocessor/riscv-target-features.c
+++ b/clang/test/Preprocessor/riscv-target-features.c
@@ -185,8 +185,10 @@
 // RUN: %clang --target=riscv64-unknown-linux-gnu \
 // RUN:   -march=rv64ia -E -dM %s \
 // RUN:   -o - | FileCheck --check-prefix=CHECK-A-EXT %s
+// CHECK-A-EXT: __INTPTR_WIDTH__ [[WIDTH:[1-9]+]]
 // CHECK-A-EXT: __riscv_a 2001000{{$}}
 // CHECK-A-EXT: __riscv_atomic 1
+// CHECK-A-EXT: __riscv_cmdline_arch_string "rv[[WIDTH]]i2p1_a2p1"
 
 // RUN: %clang --target=riscv32-unknown-linux-gnu \
 // RUN:   -march=rv32ic -E -dM %s \
@@ -203,6 +205,8 @@
 // RUN: %clang --target=riscv64-unknown-linux-gnu \
 // RUN:   -march=rv64ifd -E -dM %s \
 // RUN:   -o - | FileCheck --check-prefix=CHECK-D-EXT %s
+// CHECK-D-EXT: __INTPTR_WIDTH__ [[WIDTH:[1-9]+]]
+// CHECK-D-EXT: __riscv_cmdline_arch_string "rv[[WIDTH]]i2p1_f2p2_d2p2_zicsr2p0"
 // CHECK-D-EXT: __riscv_d 2002000{{$}}
 // CHECK-D-EXT: __riscv_fdiv 1
 // CHECK-D-EXT: __riscv_flen 64
@@ -217,6 +221,8 @@
 // CHECK-RV32E: __riscv_32e 1
 // CHECK-RV64E: __riscv_64e 1
 // CHECK-E-EXT: __riscv_abi_rve 1
+// CHECK-RV32E: __riscv_cmdline_arch_string "rv32e2p0"
+// CHECK-RV64E: __riscv_cmdline_arch_string "rv64e2p0"
 // CHECK-E-EXT: __riscv_e 2000000{{$}}
 
 // RUN: %clang --target=riscv32-unknown-linux-gnu \
@@ -225,6 +231,8 @@
 // RUN: %clang --target=riscv64-unknown-linux-gnu \
 // RUN:   -march=rv64if -E -dM %s \
 // RUN:   -o - | FileCheck --check-prefix=CHECK-F-EXT %s
+// CHECK-F-EXT: __INTPTR_WIDTH__ [[WIDTH:[1-9]+]]
+// CHECK-F-EXT: __riscv_cmdline_arch_string "rv[[WIDTH]]i2p1_f2p2_zicsr2p0"
 // CHECK-F-EXT: __riscv_f 2002000{{$}}
 // CHECK-F-EXT: __riscv_fdiv 1
 // CHECK-F-EXT: __riscv_flen 32

``````````

</details>


https://github.com/llvm/llvm-project/pull/85063