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

[Nemanja Ivanovic via cfe-commits]

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

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

>From ee8d994564e843c889a46f361edb6ca652a0589f Mon Sep 17 00:00:00 2001
From: Nemanja Ivanovic <nemanja at synopsys.com>
Date: Wed, 13 Mar 2024 12:59:42 +0100
Subject: [PATCH] [RISCV] Emit arch string macro to facilitate ASM programming

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
---
 clang/lib/Basic/Targets/RISCV.cpp               | 2 ++
 clang/test/Preprocessor/riscv-target-features.c | 8 ++++++++
 2 files changed, 10 insertions(+)

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