diff --git a/compiler/rustc_codegen_gcc/src/debuginfo.rs b/compiler/rustc_codegen_gcc/src/debuginfo.rs index d3aeb7f3bdeb3..4b84b1dbfd396 100644 --- a/compiler/rustc_codegen_gcc/src/debuginfo.rs +++ b/compiler/rustc_codegen_gcc/src/debuginfo.rs @@ -113,15 +113,15 @@ fn make_mir_scope<'gcc, 'tcx>( let scope_data = &mir.source_scopes[scope]; let parent_scope = if let Some(parent) = scope_data.parent_scope { make_mir_scope(cx, _instance, mir, variables, debug_context, instantiated, parent); - debug_context.scopes[parent].unwrap() + debug_context.scopes[parent] } else { // The root is the function itself. let file = cx.sess().source_map().lookup_source_file(mir.span.lo()); - debug_context.scopes[scope] = Some(DebugScope { + debug_context.scopes[scope] = DebugScope { file_start_pos: file.start_pos, file_end_pos: file.end_position(), - ..debug_context.scopes[scope].unwrap() - }); + ..debug_context.scopes[scope] + }; instantiated.insert(scope); return; }; @@ -130,7 +130,7 @@ fn make_mir_scope<'gcc, 'tcx>( if !vars.contains(scope) && scope_data.inlined.is_none() { // Do not create a DIScope if there are no variables defined in this // MIR `SourceScope`, and it's not `inlined`, to avoid debuginfo bloat. - debug_context.scopes[scope] = Some(parent_scope); + debug_context.scopes[scope] = parent_scope; instantiated.insert(scope); return; } @@ -157,12 +157,12 @@ fn make_mir_scope<'gcc, 'tcx>( // TODO(tempdragon): dbg_scope: Add support for scope extension here. inlined_at.or(p_inlined_at); - debug_context.scopes[scope] = Some(DebugScope { + debug_context.scopes[scope] = DebugScope { dbg_scope, inlined_at, file_start_pos: loc.file.start_pos, file_end_pos: loc.file.end_position(), - }); + }; instantiated.insert(scope); } @@ -232,12 +232,12 @@ impl<'gcc, 'tcx> DebugInfoCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> { } // Initialize fn debug context (including scopes). - let empty_scope = Some(DebugScope { + let empty_scope = DebugScope { dbg_scope: self.dbg_scope_fn(instance, fn_abi, Some(llfn)), inlined_at: None, file_start_pos: BytePos(0), file_end_pos: BytePos(0), - }); + }; let mut fn_debug_context = FunctionDebugContext { scopes: IndexVec::from_elem(empty_scope, mir.source_scopes.as_slice()), inlined_function_scopes: Default::default(), diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs b/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs index e545ce386ede2..11eb9651af6c5 100644 --- a/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs +++ b/compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs @@ -9,7 +9,7 @@ use rustc_middle::mir::{Body, SourceScope}; use rustc_middle::ty::layout::{FnAbiOf, HasTypingEnv}; use rustc_middle::ty::{self, Instance}; use rustc_session::config::DebugInfo; -use rustc_span::{BytePos, hygiene}; +use rustc_span::{BytePos, DUMMY_SP, hygiene}; use super::metadata::file_metadata; use super::utils::DIB; @@ -85,23 +85,15 @@ fn make_mir_scope<'ll, 'tcx>( discriminators, parent, ); - if let Some(parent_scope) = debug_context.scopes[parent] { - parent_scope - } else { - // If the parent scope could not be represented then no children - // can be either. - debug_context.scopes[scope] = None; - instantiated.insert(scope); - return; - } + debug_context.scopes[parent] } else { // The root is the function itself. let file = cx.sess().source_map().lookup_source_file(mir.span.lo()); - debug_context.scopes[scope] = Some(DebugScope { + debug_context.scopes[scope] = DebugScope { file_start_pos: file.start_pos, file_end_pos: file.end_position(), - ..debug_context.scopes[scope].unwrap() - }); + ..debug_context.scopes[scope] + }; instantiated.insert(scope); return; }; @@ -112,7 +104,7 @@ fn make_mir_scope<'ll, 'tcx>( { // Do not create a DIScope if there are no variables defined in this // MIR `SourceScope`, and it's not `inlined`, to avoid debuginfo bloat. - debug_context.scopes[scope] = Some(parent_scope); + debug_context.scopes[scope] = parent_scope; instantiated.insert(scope); return; } @@ -145,14 +137,7 @@ fn make_mir_scope<'ll, 'tcx>( }, }; - let mut debug_scope = Some(DebugScope { - dbg_scope, - inlined_at: parent_scope.inlined_at, - file_start_pos: loc.file.start_pos, - file_end_pos: loc.file.end_position(), - }); - - if let Some((_, callsite_span)) = scope_data.inlined { + let inlined_at = scope_data.inlined.map(|(_, callsite_span)| { let callsite_span = hygiene::walk_chain_collapsed(callsite_span, mir.span); let callsite_scope = parent_scope.adjust_dbg_scope_for_span(cx, callsite_span); let loc = cx.dbg_loc(callsite_scope, parent_scope.inlined_at, callsite_span); @@ -175,29 +160,29 @@ fn make_mir_scope<'ll, 'tcx>( // Note further that we can't key this hashtable on the span itself, // because these spans could have distinct SyntaxContexts. We have // to key on exactly what we're giving to LLVM. - let inlined_at = match discriminators.entry(callsite_span.lo()) { + match discriminators.entry(callsite_span.lo()) { Entry::Occupied(mut o) => { *o.get_mut() += 1; + // NB: We have to emit *something* here or we'll fail LLVM IR verification + // in at least some circumstances (see issue #135322) so if the required + // discriminant cannot be encoded fall back to the dummy location. unsafe { llvm::LLVMRustDILocationCloneWithBaseDiscriminator(loc, *o.get()) } + .unwrap_or_else(|| { + cx.dbg_loc(callsite_scope, parent_scope.inlined_at, DUMMY_SP) + }) } Entry::Vacant(v) => { v.insert(0); - Some(loc) - } - }; - match inlined_at { - Some(inlined_at) => { - debug_scope.as_mut().unwrap().inlined_at = Some(inlined_at); - } - None => { - // LLVM has a maximum discriminator that it can encode (currently - // it uses 12 bits for 4096 possible values). If we exceed that - // there is little we can do but drop the debug info. - debug_scope = None; + loc } } - } + }); - debug_context.scopes[scope] = debug_scope; + debug_context.scopes[scope] = DebugScope { + dbg_scope, + inlined_at: inlined_at.or(parent_scope.inlined_at), + file_start_pos: loc.file.start_pos, + file_end_pos: loc.file.end_position(), + }; instantiated.insert(scope); } diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs index 755f4816acf98..e6778411365fb 100644 --- a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs +++ b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs @@ -295,12 +295,12 @@ impl<'ll, 'tcx> DebugInfoCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> { } // Initialize fn debug context (including scopes). - let empty_scope = Some(DebugScope { + let empty_scope = DebugScope { dbg_scope: self.dbg_scope_fn(instance, fn_abi, Some(llfn)), inlined_at: None, file_start_pos: BytePos(0), file_end_pos: BytePos(0), - }); + }; let mut fn_debug_context = FunctionDebugContext { scopes: IndexVec::from_elem(empty_scope, &mir.source_scopes), inlined_function_scopes: Default::default(), diff --git a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs index 843a996d2bfe5..5924c8991ad64 100644 --- a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs +++ b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs @@ -19,9 +19,7 @@ use crate::traits::*; pub struct FunctionDebugContext<'tcx, S, L> { /// Maps from source code to the corresponding debug info scope. - /// May be None if the backend is not capable of representing the scope for - /// some reason. - pub scopes: IndexVec>>, + pub scopes: IndexVec>, /// Maps from an inlined function to its debug info declaration. pub inlined_function_scopes: FxHashMap, S>, @@ -232,7 +230,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { &self, source_info: mir::SourceInfo, ) -> Option<(Bx::DIScope, Option, Span)> { - let scope = &self.debug_context.as_ref()?.scopes[source_info.scope]?; + let scope = &self.debug_context.as_ref()?.scopes[source_info.scope]; let span = hygiene::walk_chain_collapsed(source_info.span, self.mir.span); Some((scope.adjust_dbg_scope_for_span(self.cx, span), scope.inlined_at, span)) } diff --git a/tests/run-make/llvm-location-discriminator-limit-dummy-span/main.rs b/tests/run-make/llvm-location-discriminator-limit-dummy-span/main.rs new file mode 100644 index 0000000000000..421eb4331b3ff --- /dev/null +++ b/tests/run-make/llvm-location-discriminator-limit-dummy-span/main.rs @@ -0,0 +1,3 @@ +fn main() { + other::big_function(); +} diff --git a/tests/run-make/llvm-location-discriminator-limit-dummy-span/other.rs b/tests/run-make/llvm-location-discriminator-limit-dummy-span/other.rs new file mode 100644 index 0000000000000..a3ff578ebe411 --- /dev/null +++ b/tests/run-make/llvm-location-discriminator-limit-dummy-span/other.rs @@ -0,0 +1 @@ +proc::declare_big_function!(); diff --git a/tests/run-make/llvm-location-discriminator-limit-dummy-span/proc.rs b/tests/run-make/llvm-location-discriminator-limit-dummy-span/proc.rs new file mode 100644 index 0000000000000..59d17a9be5933 --- /dev/null +++ b/tests/run-make/llvm-location-discriminator-limit-dummy-span/proc.rs @@ -0,0 +1,7 @@ +extern crate proc_macro; +use proc_macro::TokenStream; + +#[proc_macro] +pub fn declare_big_function(_input: TokenStream) -> TokenStream { + include_str!("./generated.rs").parse().unwrap() +} diff --git a/tests/run-make/llvm-location-discriminator-limit-dummy-span/rmake.rs b/tests/run-make/llvm-location-discriminator-limit-dummy-span/rmake.rs new file mode 100644 index 0000000000000..2727effe81883 --- /dev/null +++ b/tests/run-make/llvm-location-discriminator-limit-dummy-span/rmake.rs @@ -0,0 +1,65 @@ +//! Regression test for . +//! +//! We can't simply drop debuginfo location spans when LLVM's location discriminator value limit is +//! reached. Otherwise, with `-Z verify-llvm-ir` and fat LTO, LLVM will report a broken module for +//! +//! ```text +//! inlinable function call in a function with debug info must have a !dbg location +//! ``` + +//@ ignore-cross-compile +//@ needs-dynamic-linking +//@ only-nightly (requires unstable rustc flag) + +#![deny(warnings)] + +use run_make_support::{dynamic_lib_name, rfs, rust_lib_name, rustc}; + +// Synthesize a function that will have a large (`n`) number of functions +// MIR-inlined into it. When combined with a proc-macro, all of these inline +// callsites will have the same span, forcing rustc to use the DWARF +// discriminator to distinguish between them. LLVM's capacity to store that +// discriminator is not infinite (currently it allocates 12 bits for a +// maximum value of 4096) so if this function gets big enough rustc's error +// handling path will be exercised. +fn generate_program(n: u32) -> String { + let mut program = String::from("pub type BigType = Vec>;\n\n"); + program.push_str("pub fn big_function() -> BigType {\n"); + program.push_str(" vec![\n"); + for i in 1..=n { + program.push_str(&format!("vec![\"string{}\".to_owned()],\n", i)); + } + program.push_str(" ]\n"); + program.push_str("}\n"); + program +} + +fn main() { + // The reported threshold is around 1366 (4096/3), but let's bump it to + // around 1500 to be less sensitive. + rfs::write("generated.rs", generate_program(1500)); + + rustc() + .input("proc.rs") + .crate_type("proc-macro") + .edition("2021") + .arg("-Cdebuginfo=line-tables-only") + .run(); + rustc() + .extern_("proc", dynamic_lib_name("proc")) + .input("other.rs") + .crate_type("rlib") + .edition("2021") + .opt_level("3") + .arg("-Cdebuginfo=line-tables-only") + .run(); + rustc() + .extern_("other", rust_lib_name("other")) + .input("main.rs") + .edition("2021") + .opt_level("3") + .arg("-Cdebuginfo=line-tables-only") + .arg("-Clto=fat") + .arg("-Zverify-llvm-ir") + .run(); +}