Rollup merge of #137549 - oli-obk:llvm-ffi, r=davidtwco

Clean up various LLVM FFI things in codegen_llvm

cc ```@ZuseZ4``` I touched some autodiff parts

The major change of this PR is [bfd88ce](https://github.com/rust-lang/rust/pull/137549/commits/bfd88cead0dd79717f123ad7e9a26ecad88653cb) which makes `CodegenCx` generic just like `GenericBuilder`

The other commits mostly took advantage of the new feature of making extern functions safe, but also just used some wrappers that were already there and shrunk unsafe blocks.

best reviewed commit-by-commit

1 files changed, 47 insertions, 51 deletions

diff --git a/compiler/rustc_codegen_llvm/src/asm.rs b/compiler/rustc_codegen_llvm/src/asm.rs
index e8a69743157..88daa025740 100644
--- a/compiler/rustc_codegen_llvm/src/asm.rs
+++ b/compiler/rustc_codegen_llvm/src/asm.rs
@@ -1,6 +1,5 @@
 use std::assert_matches::assert_matches;
 
-use libc::{c_char, c_uint};
 use rustc_abi::{BackendRepr, Float, Integer, Primitive, Scalar};
 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
 use rustc_codegen_ssa::mir::operand::OperandValue;
@@ -483,12 +482,13 @@ pub(crate) fn inline_asm_call<'ll>(
 
     debug!("Asm Output Type: {:?}", output);
     let fty = bx.cx.type_func(&argtys, output);
-    unsafe {
-        // Ask LLVM to verify that the constraints are well-formed.
-        let constraints_ok = llvm::LLVMRustInlineAsmVerify(fty, cons.as_c_char_ptr(), cons.len());
-        debug!("constraint verification result: {:?}", constraints_ok);
-        if constraints_ok {
-            let v = llvm::LLVMRustInlineAsm(
+    // Ask LLVM to verify that the constraints are well-formed.
+    let constraints_ok =
+        unsafe { llvm::LLVMRustInlineAsmVerify(fty, cons.as_c_char_ptr(), cons.len()) };
+    debug!("constraint verification result: {:?}", constraints_ok);
+    if constraints_ok {
+        let v = unsafe {
+            llvm::LLVMRustInlineAsm(
                 fty,
                 asm.as_c_char_ptr(),
                 asm.len(),
@@ -498,54 +498,50 @@ pub(crate) fn inline_asm_call<'ll>(
                 alignstack,
                 dia,
                 can_throw,
-            );
-
-            let call = if !labels.is_empty() {
-                assert!(catch_funclet.is_none());
-                bx.callbr(fty, None, None, v, inputs, dest.unwrap(), labels, None, None)
-            } else if let Some((catch, funclet)) = catch_funclet {
-                bx.invoke(fty, None, None, v, inputs, dest.unwrap(), catch, funclet, None)
-            } else {
-                bx.call(fty, None, None, v, inputs, None, None)
-            };
+            )
+        };
 
-            // Store mark in a metadata node so we can map LLVM errors
-            // back to source locations. See #17552.
-            let key = "srcloc";
-            let kind = llvm::LLVMGetMDKindIDInContext(
-                bx.llcx,
-                key.as_ptr().cast::<c_char>(),
-                key.len() as c_uint,
-            );
+        let call = if !labels.is_empty() {
+            assert!(catch_funclet.is_none());
+            bx.callbr(fty, None, None, v, inputs, dest.unwrap(), labels, None, None)
+        } else if let Some((catch, funclet)) = catch_funclet {
+            bx.invoke(fty, None, None, v, inputs, dest.unwrap(), catch, funclet, None)
+        } else {
+            bx.call(fty, None, None, v, inputs, None, None)
+        };
 
-            // `srcloc` contains one 64-bit integer for each line of assembly code,
-            // where the lower 32 bits hold the lo byte position and the upper 32 bits
-            // hold the hi byte position.
-            let mut srcloc = vec![];
-            if dia == llvm::AsmDialect::Intel && line_spans.len() > 1 {
-                // LLVM inserts an extra line to add the ".intel_syntax", so add
-                // a dummy srcloc entry for it.
-                //
-                // Don't do this if we only have 1 line span since that may be
-                // due to the asm template string coming from a macro. LLVM will
-                // default to the first srcloc for lines that don't have an
-                // associated srcloc.
-                srcloc.push(llvm::LLVMValueAsMetadata(bx.const_u64(0)));
-            }
-            srcloc.extend(line_spans.iter().map(|span| {
-                llvm::LLVMValueAsMetadata(bx.const_u64(
-                    u64::from(span.lo().to_u32()) | (u64::from(span.hi().to_u32()) << 32),
-                ))
-            }));
-            let md = llvm::LLVMMDNodeInContext2(bx.llcx, srcloc.as_ptr(), srcloc.len());
-            let md = llvm::LLVMMetadataAsValue(&bx.llcx, md);
-            llvm::LLVMSetMetadata(call, kind, md);
+        // Store mark in a metadata node so we can map LLVM errors
+        // back to source locations. See #17552.
+        let key = "srcloc";
+        let kind = bx.get_md_kind_id(key);
 
-            Some(call)
-        } else {
-            // LLVM has detected an issue with our constraints, bail out
-            None
+        // `srcloc` contains one 64-bit integer for each line of assembly code,
+        // where the lower 32 bits hold the lo byte position and the upper 32 bits
+        // hold the hi byte position.
+        let mut srcloc = vec![];
+        if dia == llvm::AsmDialect::Intel && line_spans.len() > 1 {
+            // LLVM inserts an extra line to add the ".intel_syntax", so add
+            // a dummy srcloc entry for it.
+            //
+            // Don't do this if we only have 1 line span since that may be
+            // due to the asm template string coming from a macro. LLVM will
+            // default to the first srcloc for lines that don't have an
+            // associated srcloc.
+            srcloc.push(llvm::LLVMValueAsMetadata(bx.const_u64(0)));
         }
+        srcloc.extend(line_spans.iter().map(|span| {
+            llvm::LLVMValueAsMetadata(
+                bx.const_u64(u64::from(span.lo().to_u32()) | (u64::from(span.hi().to_u32()) << 32)),
+            )
+        }));
+        let md = unsafe { llvm::LLVMMDNodeInContext2(bx.llcx, srcloc.as_ptr(), srcloc.len()) };
+        let md = bx.get_metadata_value(md);
+        llvm::LLVMSetMetadata(call, kind, md);
+
+        Some(call)
+    } else {
+        // LLVM has detected an issue with our constraints, bail out
+        None
     }
 }