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mcdc-coverage: Add possibility for codegen llvm to handle several condition bitmaps

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This commit is contained in:
Dorian Péron 2024-04-08 14:23:50 +00:00
parent c67277301c
commit 3c2f48ede9
2 changed files with 38 additions and 18 deletions
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31
compiler/rustc_codegen_llvm/src/builder.rs
View file

@ -27,6 +27,7 @@ use rustc_target::abi::{self, call::FnAbi, Align, Size, WrappingRange};
use rustc_target::spec::{HasTargetSpec, SanitizerSet, Target};
use smallvec::SmallVec;
use std::borrow::Cow;
use std::ffi::CString;
use std::iter;
use std::ops::Deref;
use std::ptr;
@ -1708,7 +1709,8 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
fn_name: &'ll Value,
hash: &'ll Value,
bitmap_bytes: &'ll Value,
) -> &'ll Value {
max_decision_depth: u32,
) -> Vec<&'ll Value> {
debug!("mcdc_parameters() with args ({:?}, {:?}, {:?})", fn_name, hash, bitmap_bytes);
assert!(llvm_util::get_version() >= (18, 0, 0), "MCDC intrinsics require LLVM 18 or later");
@ -1721,6 +1723,8 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
let args = &[fn_name, hash, bitmap_bytes];
let args = self.check_call("call", llty, llfn, args);
let mut cond_bitmaps = vec![];
unsafe {
let _ = llvm::LLVMRustBuildCall(
self.llbuilder,
@ -1732,17 +1736,22 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
0 as c_uint,
);
// Create condition bitmap named `mcdc.addr`.
let mut bx = Builder::with_cx(self.cx);
bx.position_at_start(llvm::LLVMGetFirstBasicBlock(self.llfn()));
let cond_bitmap = {
let alloca =
llvm::LLVMBuildAlloca(bx.llbuilder, bx.cx.type_i32(), c"mcdc.addr".as_ptr());
llvm::LLVMSetAlignment(alloca, 4);
alloca
};
bx.store(self.const_i32(0), cond_bitmap, self.tcx().data_layout.i32_align.abi);
cond_bitmap
for i in 0..=max_decision_depth {
let mut bx = Builder::with_cx(self.cx);
bx.position_at_start(llvm::LLVMGetFirstBasicBlock(self.llfn()));
let name = CString::new(format!("mcdc.addr.{i}")).unwrap();
let cond_bitmap = {
let alloca =
llvm::LLVMBuildAlloca(bx.llbuilder, bx.cx.type_i32(), name.as_ptr());
llvm::LLVMSetAlignment(alloca, 4);
alloca
};
bx.store(self.const_i32(0), cond_bitmap, self.tcx().data_layout.i32_align.abi);
cond_bitmaps.push(cond_bitmap);
}
}
cond_bitmaps
}
pub(crate) fn mcdc_tvbitmap_update(

25
compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
View file

@ -30,7 +30,7 @@ pub struct CrateCoverageContext<'ll, 'tcx> {
pub(crate) function_coverage_map:
RefCell<FxIndexMap<Instance<'tcx>, FunctionCoverageCollector<'tcx>>>,
pub(crate) pgo_func_name_var_map: RefCell<FxHashMap<Instance<'tcx>, &'ll llvm::Value>>,
pub(crate) mcdc_condition_bitmap_map: RefCell<FxHashMap<Instance<'tcx>, &'ll llvm::Value>>,
pub(crate) mcdc_condition_bitmap_map: RefCell<FxHashMap<Instance<'tcx>, Vec<&'ll llvm::Value>>>,
}
impl<'ll, 'tcx> CrateCoverageContext<'ll, 'tcx> {
@ -49,9 +49,20 @@ impl<'ll, 'tcx> CrateCoverageContext<'ll, 'tcx> {
}
/// LLVM use a temp value to record evaluated mcdc test vector of each decision, which is called condition bitmap.
/// This value is named `mcdc.addr` (same as clang) and is a 32-bit integer.
fn try_get_mcdc_condition_bitmap(&self, instance: &Instance<'tcx>) -> Option<&'ll llvm::Value> {
self.mcdc_condition_bitmap_map.borrow().get(instance).copied()
/// In order to handle nested decisions, several condition bitmaps can be
/// allocated for a function body.
/// These values are named `mcdc.addr.{i}` and are a 32-bit integers.
/// They respectively hold the condition bitmaps for decisions with a depth of `i`.
fn try_get_mcdc_condition_bitmap(
&self,
instance: &Instance<'tcx>,
decision_depth: u16,
) -> Option<&'ll llvm::Value> {
self.mcdc_condition_bitmap_map
.borrow()
.get(instance)
.and_then(|bitmap_map| bitmap_map.get(decision_depth as usize))
.copied() // Dereference Option<&&Value> to Option<&Value>
}
}
@ -151,7 +162,7 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
"ConditionId of evaluated conditions should never be zero"
);
let cond_bitmap = coverage_context
.try_get_mcdc_condition_bitmap(&instance)
.try_get_mcdc_condition_bitmap(&instance, 0)
.expect("mcdc cond bitmap should have been allocated for updating");
let cond_loc = bx.const_i32(id.as_u32() as i32 - 1);
let bool_value = bx.const_bool(value);
@ -162,7 +173,7 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
CoverageKind::TestVectorBitmapUpdate { bitmap_idx } => {
drop(coverage_map);
let cond_bitmap = coverage_context
.try_get_mcdc_condition_bitmap(&instance)
.try_get_mcdc_condition_bitmap(&instance, 0)
.expect("mcdc cond bitmap should have been allocated for merging into the global bitmap");
let bitmap_bytes = bx.tcx().coverage_ids_info(instance.def).mcdc_bitmap_bytes;
assert!(bitmap_idx < bitmap_bytes, "bitmap index of the decision out of range");
@ -195,7 +206,7 @@ fn ensure_mcdc_parameters<'ll, 'tcx>(
let fn_name = bx.get_pgo_func_name_var(instance);
let hash = bx.const_u64(function_coverage_info.function_source_hash);
let bitmap_bytes = bx.const_u32(function_coverage_info.mcdc_bitmap_bytes);
let cond_bitmap = bx.mcdc_parameters(fn_name, hash, bitmap_bytes);
let cond_bitmap = bx.mcdc_parameters(fn_name, hash, bitmap_bytes, 1_u32);
bx.coverage_context()
.expect("already checked above")
.mcdc_condition_bitmap_map