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Add -cov-increment option to specify the type of increment instruction. Add atomic, non-atomic, and boolean increment types. (#3724)

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Johan Engelen 2021-06-09 12:49:07 +02:00 • committed by GitHub
parent 217e0b9c44
commit f9147a6f62
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4 changed files with 104 additions and 7 deletions
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46
gen/coverage.cpp
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@ -10,6 +10,7 @@
#include "gen/coverage.h"
#include "dmd/module.h"
#include "driver/cl_options.h"
#include "gen/irstate.h"
#include "gen/logger.h"
@ -30,21 +31,52 @@ void emitCoverageLinecountInc(const Loc &loc) {
IF_LOG Logger::println("Coverage: increment _d_cover_data[%d]", line);
LOG_SCOPE;
// Get GEP into _d_cover_data array
// Increment the line counter:
// Get GEP into _d_cover_data array...
LLConstant *idxs[] = {DtoConstUint(0), DtoConstUint(line)};
LLValue *ptr = llvm::ConstantExpr::getGetElementPtr(
LLArrayType::get(LLType::getInt32Ty(gIR->context()), m->numlines),
m->d_cover_data, idxs, true);
// ...and generate the "increment" instruction(s)
switch (opts::coverageIncrement) {
case opts::CoverageIncrement::_default: // fallthrough
case opts::CoverageIncrement::atomic:
// Do an atomic increment, so this works when multiple threads are executed.
gIR->ir->CreateAtomicRMW(llvm::AtomicRMWInst::Add, ptr, DtoConstUint(1),
llvm::AtomicOrdering::Monotonic);
break;
case opts::CoverageIncrement::nonatomic: {
// Do a non-atomic increment, user is responsible for correct results with
// multithreaded execution
llvm::LoadInst *load = gIR->ir->CreateAlignedLoad(ptr, LLAlign(4));
llvm::StoreInst *store = gIR->ir->CreateAlignedStore(
gIR->ir->CreateAdd(load, DtoConstUint(1)), ptr, LLAlign(4));
// add !nontemporal attribute, to inform the optimizer that caching is not
// needed
llvm::MDNode *node = llvm::MDNode::get(
gIR->context(), llvm::ConstantAsMetadata::get(DtoConstInt(1)));
load->setMetadata("nontemporal", node);
store->setMetadata("nontemporal", node);
break;
}
case opts::CoverageIncrement::boolean: {
// Do a boolean set, avoiding a memory read (blocking) and threading issues
// at the cost of not "counting"
llvm::StoreInst *store =
gIR->ir->CreateAlignedStore(DtoConstUint(1), ptr, LLAlign(4));
// add !nontemporal attribute, to inform the optimizer that caching is not
// needed
llvm::MDNode *node = llvm::MDNode::get(
gIR->context(), llvm::ConstantAsMetadata::get(DtoConstInt(1)));
store->setMetadata("nontemporal", node);
break;
}
}
// Do an atomic increment, so this works when multiple threads are executed.
gIR->ir->CreateAtomicRMW(llvm::AtomicRMWInst::Add, ptr, DtoConstUint(1),
llvm::AtomicOrdering::Monotonic);
// Set the 'counter valid' bit to 1 for this line of code
unsigned num_sizet_bits = gDataLayout->getTypeSizeInBits(DtoSize_t());
unsigned idx = line / num_sizet_bits;
unsigned bitidx = line % num_sizet_bits;
IF_LOG Logger::println("_d_cover_valid[%d] |= (1 << %d)", idx, bitidx);
m->d_cover_valid_init[idx] |= (size_t(1) << bitidx);
}