Rollup merge of #37636 - karpinski:issue-34915, r=nikomatsakis

Marking the 'no-stack-check' codegen option as deprecated (Issue #34915)

Attempts to finish resolving issue #34915. Based on pull request #35156, which was closed due to inactivity.

Author: eddyb

src/librustc/session/config.rs

@@ -793,7 +793,7 @@ options! {CodegenOptions, CodegenSetter, basic_codegen_options,
     remark: Passes = (SomePasses(Vec::new()), parse_passes, [UNTRACKED],
         "print remarks for these optimization passes (space separated, or \"all\")"),
     no_stack_check: bool = (false, parse_bool, [UNTRACKED],
-        "disable checks for stack exhaustion (a memory-safety hazard!)"),
+        "the --no-stack-check flag is deprecated and does nothing"),
     debuginfo: Option<usize> = (None, parse_opt_uint, [TRACKED],
         "debug info emission level, 0 = no debug info, 1 = line tables only, \
          2 = full debug info with variable and type information"),

src/librustc_driver/lib.rs

@@ -75,7 +75,7 @@ use rustc::dep_graph::DepGraph;
 use rustc::session::{self, config, Session, build_session, CompileResult};
 use rustc::session::config::{Input, PrintRequest, OutputType, ErrorOutputType};
 use rustc::session::config::nightly_options;
-use rustc::session::early_error;
+use rustc::session::{early_error, early_warn};
 use rustc::lint::Lint;
 use rustc::lint;
 use rustc_metadata::locator;
@@ -1011,6 +1011,11 @@ pub fn handle_options(args: &[String]) -> Option<getopts::Matches> {
         return None;
     }
 
+    if cg_flags.iter().any(|x| *x == "no-stack-check") {
+        early_warn(ErrorOutputType::default(),
+                   "the --no-stack-check flag is deprecated and does nothing");
+    }
+
     if cg_flags.contains(&"passes=list".to_string()) {
         unsafe {
             ::llvm::LLVMRustPrintPasses();