Rollup of 6 pull requests

src/bootstrap/bin/rustc.rs

@@ -187,33 +187,6 @@ fn main() {
             cmd.arg("-C").arg(format!("debug-assertions={}", debug_assertions));
         }
 
-        // Build all crates in the `std` facade with `-Z emit-stack-sizes` to add stack usage
-        // information.
-        //
-        // When you use this `-Z` flag with Cargo you get stack usage information on all crates
-        // compiled from source, and when you are using LTO you also get information on pre-compiled
-        // crates like `core` and `std`, even if they were not compiled with `-Z emit-stack-sizes`.
-        // However, there's an exception: `compiler_builtins`. This crate is special and doesn't
-        // participate in LTO because it's always linked as a separate object file. For this reason
-        // it's impossible to get stack usage information about `compiler-builtins` using
-        // `RUSTFLAGS` + Cargo, or `cargo rustc`.
-        //
-        // To make the stack usage information of all crates under the `std` facade available to
-        // Cargo based stack usage analysis tools, in both LTO and non-LTO mode, we compile them
-        // with the `-Z emit-stack-sizes` flag. The `RUSTC_EMIT_STACK_SIZES` var helps us apply this
-        // flag only to the crates in the `std` facade. The `-Z` flag is known to currently work
-        // with targets that produce ELF files so we limit its use flag to those targets.
-        //
-        // NOTE(japaric) if this ever causes problem with an LLVM upgrade or any PR feel free to
-        // remove it or comment it out
-        if env::var_os("RUSTC_EMIT_STACK_SIZES").is_some()
-            && (target.contains("-linux-")
-                || target.contains("-none-eabi")
-                || target.ends_with("-none-elf"))
-        {
-            cmd.arg("-Zemit-stack-sizes");
-        }
-
         if let Ok(s) = env::var("RUSTC_CODEGEN_UNITS") {
             cmd.arg("-C").arg(format!("codegen-units={}", s));
         }

src/bootstrap/compile.rs

@@ -97,8 +97,6 @@ impl Step for Std {
         let _folder = builder.fold_output(|| format!("stage{}-std", compiler.stage));
         builder.info(&format!("Building stage{} std artifacts ({} -> {})", compiler.stage,
                 &compiler.host, target));
-        // compile with `-Z emit-stack-sizes`; see bootstrap/src/rustc.rs for more details
-        cargo.env("RUSTC_EMIT_STACK_SIZES", "1");
         run_cargo(builder,
                   &mut cargo,
                   &libstd_stamp(builder, compiler, target),
@@ -397,8 +395,6 @@ impl Step for Test {
         let _folder = builder.fold_output(|| format!("stage{}-test", compiler.stage));
         builder.info(&format!("Building stage{} test artifacts ({} -> {})", compiler.stage,
                 &compiler.host, target));
-        // compile with `-Z emit-stack-sizes`; see bootstrap/src/rustc.rs for more details
-        cargo.env("RUSTC_EMIT_STACK_SIZES", "1");
         run_cargo(builder,
                   &mut cargo,
                   &libtest_stamp(builder, compiler, target),

src/librustc/session/config.rs

@@ -113,6 +113,21 @@ impl LinkerPluginLto {
     }
 }
 
+#[derive(Clone, PartialEq, Hash)]
+pub enum PgoGenerate {
+    Enabled(Option<PathBuf>),
+    Disabled,
+}
+
+impl PgoGenerate {
+    pub fn enabled(&self) -> bool {
+        match *self {
+            PgoGenerate::Enabled(_) => true,
+            PgoGenerate::Disabled => false,
+        }
+    }
+}
+
 #[derive(Clone, Copy, PartialEq, Hash)]
 pub enum DebugInfo {
     None,
@@ -826,13 +841,15 @@ macro_rules! options {
         pub const parse_linker_plugin_lto: Option<&str> =
             Some("either a boolean (`yes`, `no`, `on`, `off`, etc), \
                   or the path to the linker plugin");
+        pub const parse_pgo_generate: Option<&str> =
+            Some("an optional path to the profiling data output directory");
         pub const parse_merge_functions: Option<&str> =
             Some("one of: `disabled`, `trampolines`, or `aliases`");
     }
 
     #[allow(dead_code)]
     mod $mod_set {
-        use super::{$struct_name, Passes, Sanitizer, LtoCli, LinkerPluginLto};
+        use super::{$struct_name, Passes, Sanitizer, LtoCli, LinkerPluginLto, PgoGenerate};
         use rustc_target::spec::{LinkerFlavor, MergeFunctions, PanicStrategy, RelroLevel};
         use std::path::PathBuf;
         use std::str::FromStr;
@@ -1087,6 +1104,14 @@ macro_rules! options {
             true
         }
 
+        fn parse_pgo_generate(slot: &mut PgoGenerate, v: Option<&str>) -> bool {
+            *slot = match v {
+                None => PgoGenerate::Enabled(None),
+                Some(path) => PgoGenerate::Enabled(Some(PathBuf::from(path))),
+            };
+            true
+        }
+
         fn parse_merge_functions(slot: &mut Option<MergeFunctions>, v: Option<&str>) -> bool {
             match v.and_then(|s| MergeFunctions::from_str(s).ok()) {
                 Some(mergefunc) => *slot = Some(mergefunc),
@@ -1363,7 +1388,7 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "extra arguments to prepend to the linker invocation (space separated)"),
     profile: bool = (false, parse_bool, [TRACKED],
                      "insert profiling code"),
-    pgo_gen: Option<String> = (None, parse_opt_string, [TRACKED],
+    pgo_gen: PgoGenerate = (PgoGenerate::Disabled, parse_pgo_generate, [TRACKED],
         "Generate PGO profile data, to a given file, or to the default location if it's empty."),
     pgo_use: String = (String::new(), parse_string, [TRACKED],
         "Use PGO profile data from the given profile file."),
@@ -1980,7 +2005,7 @@ pub fn build_session_options_and_crate_config(
         );
     }
 
-    if debugging_opts.pgo_gen.is_some() && !debugging_opts.pgo_use.is_empty() {
+    if debugging_opts.pgo_gen.enabled() && !debugging_opts.pgo_use.is_empty() {
         early_error(
             error_format,
             "options `-Z pgo-gen` and `-Z pgo-use` are exclusive",
@@ -2490,7 +2515,7 @@ mod dep_tracking {
     use std::path::PathBuf;
     use std::collections::hash_map::DefaultHasher;
     use super::{CrateType, DebugInfo, ErrorOutputType, OptLevel, OutputTypes,
-                Passes, Sanitizer, LtoCli, LinkerPluginLto};
+                Passes, Sanitizer, LtoCli, LinkerPluginLto, PgoGenerate};
     use syntax::feature_gate::UnstableFeatures;
     use rustc_target::spec::{MergeFunctions, PanicStrategy, RelroLevel, TargetTriple};
     use syntax::edition::Edition;
@@ -2558,6 +2583,7 @@ mod dep_tracking {
     impl_dep_tracking_hash_via_hash!(TargetTriple);
     impl_dep_tracking_hash_via_hash!(Edition);
     impl_dep_tracking_hash_via_hash!(LinkerPluginLto);
+    impl_dep_tracking_hash_via_hash!(PgoGenerate);
 
     impl_dep_tracking_hash_for_sortable_vec_of!(String);
     impl_dep_tracking_hash_for_sortable_vec_of!(PathBuf);
@@ -2625,7 +2651,7 @@ mod tests {
         build_session_options_and_crate_config,
         to_crate_config
     };
-    use crate::session::config::{LtoCli, LinkerPluginLto};
+    use crate::session::config::{LtoCli, LinkerPluginLto, PgoGenerate};
     use crate::session::build_session;
     use crate::session::search_paths::SearchPath;
     use std::collections::{BTreeMap, BTreeSet};
@@ -3124,7 +3150,7 @@ mod tests {
         assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
 
         opts = reference.clone();
-        opts.debugging_opts.pgo_gen = Some(String::from("abc"));
+        opts.debugging_opts.pgo_gen = PgoGenerate::Enabled(None);
         assert_ne!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
 
         opts = reference.clone();

src/librustc_codegen_llvm/attributes.rs

@@ -104,7 +104,7 @@ pub fn set_probestack(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
     }
 
     // probestack doesn't play nice either with pgo-gen.
-    if cx.sess().opts.debugging_opts.pgo_gen.is_some() {
+    if cx.sess().opts.debugging_opts.pgo_gen.enabled() {
         return;
     }
 

src/librustc_codegen_llvm/back/link.rs

@@ -1014,7 +1014,7 @@ fn link_args(cmd: &mut dyn Linker,
         cmd.build_static_executable();
     }
 
-    if sess.opts.debugging_opts.pgo_gen.is_some() {
+    if sess.opts.debugging_opts.pgo_gen.enabled() {
         cmd.pgo_gen();
     }
 

src/librustc_codegen_llvm/back/write.rs

@@ -13,7 +13,7 @@ use crate::LlvmCodegenBackend;
 use rustc::hir::def_id::LOCAL_CRATE;
 use rustc_codegen_ssa::back::write::{CodegenContext, ModuleConfig, run_assembler};
 use rustc_codegen_ssa::traits::*;
-use rustc::session::config::{self, OutputType, Passes, Lto};
+use rustc::session::config::{self, OutputType, Passes, Lto, PgoGenerate};
 use rustc::session::Session;
 use rustc::ty::TyCtxt;
 use rustc_codegen_ssa::{ModuleCodegen, CompiledModule};
@@ -25,7 +25,7 @@ use errors::{Handler, FatalError};
 use std::ffi::{CString, CStr};
 use std::fs;
 use std::io::{self, Write};
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::str;
 use std::sync::Arc;
 use std::slice;
@@ -706,10 +706,20 @@ pub unsafe fn with_llvm_pmb(llmod: &llvm::Module,
         .unwrap_or(llvm::CodeGenOptSizeNone);
     let inline_threshold = config.inline_threshold;
 
-    let pgo_gen_path = config.pgo_gen.as_ref().map(|s| {
-        let s = if s.is_empty() { "default_%m.profraw" } else { s };
-        CString::new(s.as_bytes()).unwrap()
-    });
+    let pgo_gen_path = match config.pgo_gen {
+        PgoGenerate::Enabled(ref opt_dir_path) => {
+            let path = if let Some(dir_path) = opt_dir_path {
+                dir_path.join("default_%m.profraw")
+            } else {
+                PathBuf::from("default_%m.profraw")
+            };
+
+            Some(CString::new(format!("{}", path.display())).unwrap())
+        }
+        PgoGenerate::Disabled => {
+            None
+        }
+    };
 
     let pgo_use_path = if config.pgo_use.is_empty() {
         None
@@ -793,21 +803,31 @@ fn create_msvc_imps(
     } else {
         "\x01__imp_"
     };
+
     unsafe {
         let i8p_ty = Type::i8p_llcx(llcx);
         let globals = base::iter_globals(llmod)
             .filter(|&val| {
                 llvm::LLVMRustGetLinkage(val) == llvm::Linkage::ExternalLinkage &&
                     llvm::LLVMIsDeclaration(val) == 0
             })
-            .map(move |val| {
+            .filter_map(|val| {
+                // Exclude some symbols that we know are not Rust symbols.
                 let name = CStr::from_ptr(llvm::LLVMGetValueName(val));
+                if ignored(name.to_bytes()) {
+                    None
+                } else {
+                    Some((val, name))
+                }
+            })
+            .map(move |(val, name)| {
                 let mut imp_name = prefix.as_bytes().to_vec();
                 imp_name.extend(name.to_bytes());
                 let imp_name = CString::new(imp_name).unwrap();
                 (imp_name, val)
             })
             .collect::<Vec<_>>();
+
         for (imp_name, val) in globals {
             let imp = llvm::LLVMAddGlobal(llmod,
                                           i8p_ty,
@@ -816,4 +836,10 @@ fn create_msvc_imps(
             llvm::LLVMRustSetLinkage(imp, llvm::Linkage::ExternalLinkage);
         }
     }
+
+    // Use this function to exclude certain symbols from `__imp` generation.
+    fn ignored(symbol_name: &[u8]) -> bool {
+        // These are symbols generated by LLVM's profiling instrumentation
+        symbol_name.starts_with(b"__llvm_profile_")
+    }
 }

src/librustc_codegen_ssa/back/symbol_export.rs

@@ -209,7 +209,7 @@ fn exported_symbols_provider_local<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         }
     }
 
-    if tcx.sess.opts.debugging_opts.pgo_gen.is_some() {
+    if tcx.sess.opts.debugging_opts.pgo_gen.enabled() {
         // These are weak symbols that point to the profile version and the
         // profile name, which need to be treated as exported so LTO doesn't nix
         // them.

src/librustc_codegen_ssa/back/write.rs

@@ -12,7 +12,8 @@ use rustc_incremental::{copy_cgu_workproducts_to_incr_comp_cache_dir,
 use rustc::dep_graph::{WorkProduct, WorkProductId, WorkProductFileKind};
 use rustc::dep_graph::cgu_reuse_tracker::CguReuseTracker;
 use rustc::middle::cstore::EncodedMetadata;
-use rustc::session::config::{self, OutputFilenames, OutputType, Passes, Sanitizer, Lto};
+use rustc::session::config::{self, OutputFilenames, OutputType, Passes, Lto,
+                             Sanitizer, PgoGenerate};
 use rustc::session::Session;
 use rustc::util::nodemap::FxHashMap;
 use rustc::hir::def_id::{CrateNum, LOCAL_CRATE};
@@ -55,7 +56,7 @@ pub struct ModuleConfig {
     /// Some(level) to optimize binary size, or None to not affect program size.
     pub opt_size: Option<config::OptLevel>,
 
-    pub pgo_gen: Option<String>,
+    pub pgo_gen: PgoGenerate,
     pub pgo_use: String,
 
     // Flags indicating which outputs to produce.
@@ -93,7 +94,7 @@ impl ModuleConfig {
             opt_level: None,
             opt_size: None,
 
-            pgo_gen: None,
+            pgo_gen: PgoGenerate::Disabled,
             pgo_use: String::new(),
 
             emit_no_opt_bc: false,

src/librustc_metadata/creader.rs

@@ -862,7 +862,7 @@ impl<'a> CrateLoader<'a> {
 
     fn inject_profiler_runtime(&mut self) {
         if self.sess.opts.debugging_opts.profile ||
-            self.sess.opts.debugging_opts.pgo_gen.is_some()
+            self.sess.opts.debugging_opts.pgo_gen.enabled()
         {
             info!("loading profiler");