Pass end position of span through inline ASM cookie

Author: beetrees

compiler/rustc_codegen_llvm/src/asm.rs

@@ -487,14 +487,13 @@ pub(crate) fn inline_asm_call<'ll>(
             let key = "srcloc";
             let kind = llvm::LLVMGetMDKindIDInContext(
                 bx.llcx,
-                key.as_ptr() as *const c_char,
+                key.as_ptr().cast::<c_char>(),
                 key.len() as c_uint,
             );
 
-            // srcloc contains one integer for each line of assembly code.
-            // Unfortunately this isn't enough to encode a full span so instead
-            // we just encode the start position of each line.
-            // FIXME: Figure out a way to pass the entire line spans.
+            // `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
@@ -504,13 +503,13 @@ pub(crate) fn inline_asm_call<'ll>(
                 // 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_i32(0)));
+                srcloc.push(llvm::LLVMValueAsMetadata(bx.const_u64(0)));
             }
-            srcloc.extend(
-                line_spans
-                    .iter()
-                    .map(|span| llvm::LLVMValueAsMetadata(bx.const_i32(span.lo().to_u32() as i32))),
-            );
+            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);

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -24,8 +24,8 @@ use rustc_session::Session;
 use rustc_session::config::{
     self, Lto, OutputType, Passes, RemapPathScopeComponents, SplitDwarfKind, SwitchWithOptPath,
 };
-use rustc_span::InnerSpan;
 use rustc_span::symbol::sym;
+use rustc_span::{BytePos, InnerSpan, Pos, SpanData, SyntaxContext};
 use rustc_target::spec::{CodeModel, RelocModel, SanitizerSet, SplitDebuginfo, TlsModel};
 use tracing::debug;
 
@@ -411,21 +411,32 @@ fn report_inline_asm(
     cgcx: &CodegenContext<LlvmCodegenBackend>,
     msg: String,
     level: llvm::DiagnosticLevel,
-    mut cookie: u64,
+    cookie: u64,
     source: Option<(String, Vec<InnerSpan>)>,
 ) {
     // In LTO build we may get srcloc values from other crates which are invalid
     // since they use a different source map. To be safe we just suppress these
     // in LTO builds.
-    if matches!(cgcx.lto, Lto::Fat | Lto::Thin) {
-        cookie = 0;
-    }
+    let span = if cookie == 0 || matches!(cgcx.lto, Lto::Fat | Lto::Thin) {
+        SpanData::default()
+    } else {
+        let lo = BytePos::from_u32(cookie as u32);
+        let hi = BytePos::from_u32((cookie >> 32) as u32);
+        SpanData {
+            lo,
+            // LLVM version < 19 silently truncates the cookie to 32 bits in some situations.
+            hi: if hi.to_u32() != 0 { hi } else { lo },
+            ctxt: SyntaxContext::root(),
+            parent: None,
+        }
+    };
     let level = match level {
         llvm::DiagnosticLevel::Error => Level::Error,
         llvm::DiagnosticLevel::Warning => Level::Warning,
         llvm::DiagnosticLevel::Note | llvm::DiagnosticLevel::Remark => Level::Note,
     };
-    cgcx.diag_emitter.inline_asm_error(cookie.try_into().unwrap(), msg, level, source);
+    let msg = msg.strip_prefix("error: ").unwrap_or(&msg).to_string();
+    cgcx.diag_emitter.inline_asm_error(span, msg, level, source);
 }
 
 unsafe extern "C" fn diagnostic_handler(info: &DiagnosticInfo, user: *mut c_void) {

compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs

@@ -151,7 +151,7 @@ impl InlineAsmDiagnostic {
             unsafe { SrcMgrDiagnostic::unpack(super::LLVMRustGetSMDiagnostic(di, &mut cookie)) };
         InlineAsmDiagnostic {
             level: smdiag.level,
-            cookie: cookie.into(),
+            cookie,
             message: smdiag.message,
             source: smdiag.source,
         }

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -2271,7 +2271,7 @@ unsafe extern "C" {
 
     pub fn LLVMRustGetSMDiagnostic<'a>(
         DI: &'a DiagnosticInfo,
-        cookie_out: &mut c_uint,
+        cookie_out: &mut u64,
     ) -> &'a SMDiagnostic;
 
     #[allow(improper_ctypes)]

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -34,7 +34,7 @@ use rustc_session::config::{
 };
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::sym;
-use rustc_span::{BytePos, FileName, InnerSpan, Pos, Span};
+use rustc_span::{FileName, InnerSpan, Span, SpanData};
 use rustc_target::spec::{MergeFunctions, SanitizerSet};
 use tracing::debug;
 
@@ -1852,7 +1852,7 @@ fn spawn_work<'a, B: ExtraBackendMethods>(
 
 enum SharedEmitterMessage {
     Diagnostic(Diagnostic),
-    InlineAsmError(u32, String, Level, Option<(String, Vec<InnerSpan>)>),
+    InlineAsmError(SpanData, String, Level, Option<(String, Vec<InnerSpan>)>),
     Fatal(String),
 }
 
@@ -1874,12 +1874,12 @@ impl SharedEmitter {
 
     pub fn inline_asm_error(
         &self,
-        cookie: u32,
+        span: SpanData,
         msg: String,
         level: Level,
         source: Option<(String, Vec<InnerSpan>)>,
     ) {
-        drop(self.sender.send(SharedEmitterMessage::InlineAsmError(cookie, msg, level, source)));
+        drop(self.sender.send(SharedEmitterMessage::InlineAsmError(span, msg, level, source)));
     }
 
     fn fatal(&self, msg: &str) {
@@ -1964,17 +1964,12 @@ impl SharedEmitterMain {
                     dcx.emit_diagnostic(d);
                     sess.dcx().abort_if_errors();
                 }
-                Ok(SharedEmitterMessage::InlineAsmError(cookie, msg, level, source)) => {
+                Ok(SharedEmitterMessage::InlineAsmError(span, msg, level, source)) => {
                     assert_matches!(level, Level::Error | Level::Warning | Level::Note);
-                    let msg = msg.strip_prefix("error: ").unwrap_or(&msg).to_string();
                     let mut err = Diag::<()>::new(sess.dcx(), level, msg);
-
-                    // If the cookie is 0 then we don't have span information.
-                    if cookie != 0 {
-                        let pos = BytePos::from_u32(cookie);
-                        let span = Span::with_root_ctxt(pos, pos);
-                        err.span(span);
-                    };
+                    if !span.is_dummy() {
+                        err.span(span.span());
+                    }
 
                     // Point to the generated assembly if it is available.
                     if let Some((buffer, spans)) = source {

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -1445,7 +1445,7 @@ extern "C" LLVMTypeKind LLVMRustGetTypeKind(LLVMTypeRef Ty) {
 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(SMDiagnostic, LLVMSMDiagnosticRef)
 
 extern "C" LLVMSMDiagnosticRef LLVMRustGetSMDiagnostic(LLVMDiagnosticInfoRef DI,
-                                                       unsigned *Cookie) {
+                                                       uint64_t *Cookie) {
   llvm::DiagnosticInfoSrcMgr *SM =
       static_cast<llvm::DiagnosticInfoSrcMgr *>(unwrap(DI));
   *Cookie = SM->getLocCookie();

compiler/rustc_span/src/lib.rs

@@ -521,6 +521,12 @@ impl SpanData {
     }
 }
 
+impl Default for SpanData {
+    fn default() -> Self {
+        Self { lo: BytePos(0), hi: BytePos(0), ctxt: SyntaxContext::root(), parent: None }
+    }
+}
+
 // The interner is pointed to by a thread local value which is only set on the main thread
 // with parallelization is disabled. So we don't allow `Span` to transfer between threads
 // to avoid panics and other errors, even though it would be memory safe to do so.