Rollup merge of #93219 - cr1901:msp430-asm-squashed, r=Amanieu

Add preliminary support for inline assembly for msp430.

The `llvm_asm` macro was removed recently, and the MSP430 backend relies on inline assembly to build useful embedded apps. I conveniently "found" time to implement basic support for the new inline `asm` macro syntax with the help of `@Amanieu` :D.

In addition to tests in the compiler, I have tested this locally against deployed MSP430 code and have not found any noticeable differences in firmware operation or `objdump` disassemblies between the old `llvm_asm` and the new `asm` syntax.

1 files changed, 6 insertions, 0 deletions

diff --git a/compiler/rustc_codegen_llvm/src/asm.rs b/compiler/rustc_codegen_llvm/src/asm.rs
index 8b696dc6fba..e22bec24951 100644
--- a/compiler/rustc_codegen_llvm/src/asm.rs
+++ b/compiler/rustc_codegen_llvm/src/asm.rs
@@ -232,6 +232,9 @@ impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
                 InlineAsmArch::SpirV => {}
                 InlineAsmArch::Wasm32 | InlineAsmArch::Wasm64 => {}
                 InlineAsmArch::Bpf => {}
+                InlineAsmArch::Msp430 => {
+                    constraints.push("~{sr}".to_string());
+                }
             }
         }
         if !options.contains(InlineAsmOptions::NOMEM) {
@@ -580,6 +583,7 @@ fn reg_to_llvm(reg: InlineAsmRegOrRegClass, layout: Option<&TyAndLayout<'_>>) ->
             InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_ptr) => "e",
             InlineAsmRegClass::S390x(S390xInlineAsmRegClass::reg) => "r",
             InlineAsmRegClass::S390x(S390xInlineAsmRegClass::freg) => "f",
+            InlineAsmRegClass::Msp430(Msp430InlineAsmRegClass::reg) => "r",
             InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => {
                 bug!("LLVM backend does not support SPIR-V")
             }
@@ -666,6 +670,7 @@ fn modifier_to_llvm(
         },
         InlineAsmRegClass::Avr(_) => None,
         InlineAsmRegClass::S390x(_) => None,
+        InlineAsmRegClass::Msp430(_) => None,
         InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => {
             bug!("LLVM backend does not support SPIR-V")
         }
@@ -734,6 +739,7 @@ fn dummy_output_type<'ll>(cx: &CodegenCx<'ll, '_>, reg: InlineAsmRegClass) -> &'
         InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_ptr) => cx.type_i16(),
         InlineAsmRegClass::S390x(S390xInlineAsmRegClass::reg) => cx.type_i32(),
         InlineAsmRegClass::S390x(S390xInlineAsmRegClass::freg) => cx.type_f64(),
+        InlineAsmRegClass::Msp430(Msp430InlineAsmRegClass::reg) => cx.type_i16(),
         InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => {
             bug!("LLVM backend does not support SPIR-V")
         }