Rollup merge of #133422 - taiki-e:riscv-e-clobber-abi, r=Amanieu

Fix clobber_abi in RV32E and RV64E inline assembly

Currently clobber_abi in RV32E and RV64E inline assembly is implemented using InlineAsmClobberAbi::RiscV, but broken since x16-x31 cannot be used in RV32E and RV64E.

```
error: cannot use register `x16`: register can't be used with the `e` target feature
  --> <source>:42:14
   |
42 |     asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
   |              ^^^^^^^^^^^^^^^^

error: cannot use register `x17`: register can't be used with the `e` target feature
  --> <source>:42:14
   |
42 |     asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
   |              ^^^^^^^^^^^^^^^^

error: cannot use register `x28`: register can't be used with the `e` target feature
  --> <source>:42:14
   |
42 |     asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
   |              ^^^^^^^^^^^^^^^^

error: cannot use register `x29`: register can't be used with the `e` target feature
  --> <source>:42:14
   |
42 |     asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
   |              ^^^^^^^^^^^^^^^^

error: cannot use register `x30`: register can't be used with the `e` target feature
  --> <source>:42:14
   |
42 |     asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
   |              ^^^^^^^^^^^^^^^^

error: cannot use register `x31`: register can't be used with the `e` target feature
  --> <source>:42:14
   |
42 |     asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
   |              ^^^^^^^^^^^^^^^^
```

r? `@Amanieu`

`@rustbot` label O-riscv +A-inline-assembly

compiler/rustc_target/src/asm/mod.rs

@@ -929,6 +929,7 @@ pub enum InlineAsmClobberAbi {
     AArch64NoX18,
     Arm64EC,
     RiscV,
+    RiscVE,
     LoongArch,
     PowerPC,
     S390x,
@@ -941,6 +942,7 @@ impl InlineAsmClobberAbi {
     pub fn parse(
         arch: InlineAsmArch,
         target: &Target,
+        target_features: &FxIndexSet<Symbol>,
         name: Symbol,
     ) -> Result<Self, &'static [&'static str]> {
         let name = name.as_str();
@@ -975,7 +977,11 @@ impl InlineAsmClobberAbi {
                 _ => Err(&["C", "system"]),
             },
             InlineAsmArch::RiscV32 | InlineAsmArch::RiscV64 => match name {
-                "C" | "system" | "efiapi" => Ok(InlineAsmClobberAbi::RiscV),
+                "C" | "system" | "efiapi" => Ok(if riscv::is_e(target_features) {
+                    InlineAsmClobberAbi::RiscVE
+                } else {
+                    InlineAsmClobberAbi::RiscV
+                }),
                 _ => Err(&["C", "system", "efiapi"]),
             },
             InlineAsmArch::LoongArch64 => match name {
@@ -1148,6 +1154,31 @@ impl InlineAsmClobberAbi {
                     v24, v25, v26, v27, v28, v29, v30, v31,
                 }
             },
+            InlineAsmClobberAbi::RiscVE => clobbered_regs! {
+                RiscV RiscVInlineAsmReg {
+                    // Refs:
+                    // - ILP32E https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/draft-20240829-13bfa9f54634cb60d86b9b333e109f077805b4b3/riscv-cc.adoc#ilp32e-calling-convention
+                    // - LP64E https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/299
+
+                    // ra
+                    x1,
+                    // t0-t2
+                    x5, x6, x7,
+                    // a0-a5
+                    x10, x11, x12, x13, x14, x15,
+                    // ft0-ft7
+                    f0, f1, f2, f3, f4, f5, f6, f7,
+                    // fa0-fa7
+                    f10, f11, f12, f13, f14, f15, f16, f17,
+                    // ft8-ft11
+                    f28, f29, f30, f31,
+
+                    v0, v1, v2, v3, v4, v5, v6, v7,
+                    v8, v9, v10, v11, v12, v13, v14, v15,
+                    v16, v17, v18, v19, v20, v21, v22, v23,
+                    v24, v25, v26, v27, v28, v29, v30, v31,
+                }
+            },
             InlineAsmClobberAbi::LoongArch => clobbered_regs! {
                 LoongArch LoongArchInlineAsmReg {
                     // ra

compiler/rustc_target/src/asm/riscv.rs

@@ -54,6 +54,10 @@ impl RiscVInlineAsmRegClass {
     }
 }
 
+pub(crate) fn is_e(target_features: &FxIndexSet<Symbol>) -> bool {
+    target_features.contains(&sym::e)
+}
+
 fn not_e(
     _arch: InlineAsmArch,
     _reloc_model: RelocModel,
@@ -61,7 +65,7 @@ fn not_e(
     _target: &Target,
     _is_clobber: bool,
 ) -> Result<(), &'static str> {
-    if target_features.contains(&sym::e) {
+    if is_e(target_features) {
         Err("register can't be used with the `e` target feature")
     } else {
         Ok(())