squiid/rust
1
0
Fork 0
Code Issues Pull requests Projects Activity

Updated query for num_counters to compute from max index

Browse source 
Also added FIXME comments to note the possible need to accommodate
counter increment calls in source-based functions that differ from the
function context of the caller instance (e.g., inline functions).
This commit is contained in:
Rich Kadel 2020-06-22 23:31:41 -07:00
parent a045140268
commit 977ce57d91
2 changed files with 27 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
src/librustc_codegen_llvm/intrinsic.rs
View file

@ -140,6 +140,9 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
self.call(llfn, &[], None)
}
"count_code_region" => {
// FIXME(richkadel): The current implementation assumes the MIR for the given
// caller_instance represents a single function. Validate and/or correct if inlining
// and/or monomorphization invalidates these assumptions.
let coverage_data = tcx.coverage_data(caller_instance.def_id());
let mangled_fn = tcx.symbol_name(caller_instance);
let (mangled_fn_name, _len_val) = self.const_str(mangled_fn.name);

28
src/librustc_mir/transform/instrument_coverage.rs
View file

@ -5,15 +5,15 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_hir::lang_items;
use rustc_middle::hir;
use rustc_middle::ich::StableHashingContext;
use rustc_middle::mir::interpret::Scalar;
use rustc_middle::mir::interpret::{ConstValue, Scalar};
use rustc_middle::mir::{
self, traversal, BasicBlock, BasicBlockData, CoverageData, Operand, Place, SourceInfo,
StatementKind, Terminator, TerminatorKind, START_BLOCK,
};
use rustc_middle::ty;
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::FnDef;
use rustc_middle::ty::TyCtxt;
use rustc_middle::ty::{ConstKind, FnDef};
use rustc_span::def_id::DefId;
use rustc_span::Span;
@ -26,16 +26,36 @@ pub struct InstrumentCoverage;
pub(crate) fn provide(providers: &mut Providers<'_>) {
providers.coverage_data = |tcx, def_id| {
let mir_body = tcx.optimized_mir(def_id);
// FIXME(richkadel): The current implementation assumes the MIR for the given DefId
// represents a single function. Validate and/or correct if inlining and/or monomorphization
// invalidates these assumptions.
let count_code_region_fn =
tcx.require_lang_item(lang_items::CountCodeRegionFnLangItem, None);
let mut num_counters: u32 = 0;
// The `num_counters` argument to `llvm.instrprof.increment` is the number of injected
// counters, with each counter having an index from `0..num_counters-1`. MIR optimization
// may split and duplicate some BasicBlock sequences. Simply counting the calls may not
// not work; but computing the num_counters by adding `1` to the highest index (for a given
// instrumented function) is valid.
for (_, data) in traversal::preorder(mir_body) {
if let Some(terminator) = &data.terminator {
if let TerminatorKind::Call { func: Operand::Constant(func), .. } = &terminator.kind
if let TerminatorKind::Call { func: Operand::Constant(func), args, .. } =
&terminator.kind
{
if let FnDef(called_fn_def_id, _) = func.literal.ty.kind {
if called_fn_def_id == count_code_region_fn {
num_counters += 1;
if let Operand::Constant(constant) =
args.get(0).expect("count_code_region has at least one arg")
{
if let ConstKind::Value(ConstValue::Scalar(value)) =
constant.literal.val
{
let index = value
.to_u32()
.expect("count_code_region index at arg0 is u32");
num_counters = std::cmp::max(num_counters, index + 1);
}
}
}
}
}