Auto merge of #132791 - tyilo:big-file-fail-fast, r=compiler-errors

rustc: Fail fast when compiling a source file larger than 4 GiB

Currently if you try to compile a file that is larger than 4 GiB, `rustc` will first read the whole into memory before failing.

If we can read the metadata of the file, we can fail before reading the file.

1 files changed, 5 insertions, 0 deletions

diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 8966cfc9171..1481e1cbd91 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -1829,6 +1829,8 @@ impl StableSourceFileId {
 }
 
 impl SourceFile {
+    const MAX_FILE_SIZE: u32 = u32::MAX - 1;
+
     pub fn new(
         name: FileName,
         mut src: String,
@@ -1849,6 +1851,9 @@ impl SourceFile {
         let stable_id = StableSourceFileId::from_filename_in_current_crate(&name);
         let source_len = src.len();
         let source_len = u32::try_from(source_len).map_err(|_| OffsetOverflowError)?;
+        if source_len > Self::MAX_FILE_SIZE {
+            return Err(OffsetOverflowError);
+        }
 
         let (lines, multibyte_chars) = analyze_source_file::analyze_source_file(&src);