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[AMDGPU] Debug dump for AMDGPU resource usage #122952

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merged 3 commits into from
Mar 4, 2025
Merged

[AMDGPU] Debug dump for AMDGPU resource usage #122952

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55d4094
[AMDGPU] Debug dump for resource usage
JanekvO Jan 14, 2025
7e74618
Char-ify some lone newlines
JanekvO Mar 4, 2025
da953be
Remove clang-format (commented) markers
JanekvO Mar 4, 2025
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38 changes: 37 additions & 1 deletion llvm/lib/Target/AMDGPU/AMDGPUMCResourceInfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,8 @@
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/TargetMachine.h"

#define DEBUG_TYPE "amdgpu-mc-resource-usage"

using namespace llvm;

MCSymbol *MCResourceInfo::getSymbol(StringRef FuncName, ResourceInfoKind RIK,
Expand Down Expand Up @@ -106,6 +108,8 @@ void MCResourceInfo::assignResourceInfoExpr(
MCConstantExpr::create(LocalValue, OutContext);
const MCExpr *SymVal = LocalConstExpr;
MCSymbol *Sym = getSymbol(FnSym->getName(), RIK, OutContext, IsLocal);
LLVM_DEBUG(dbgs() << "MCResUse: " << Sym->getName() << ": Adding "
<< LocalValue << " as function local usage\n");
if (!Callees.empty()) {
SmallVector<const MCExpr *, 8> ArgExprs;
SmallPtrSet<const Function *, 8> Seen;
Expand All @@ -125,8 +129,13 @@ void MCResourceInfo::assignResourceInfoExpr(
if (!CalleeValSym->isVariable() ||
!CalleeValSym->getVariableValue(/*isUsed=*/false)
->isSymbolUsedInExpression(Sym)) {
LLVM_DEBUG(dbgs() << "MCResUse: " << Sym->getName() << ": Adding "
<< CalleeValSym->getName() << " as callee\n");
ArgExprs.push_back(MCSymbolRefExpr::create(CalleeValSym, OutContext));
} else {
LLVM_DEBUG(
dbgs() << "MCResUse: " << Sym->getName()
<< ": Recursion found, falling back to module maximum\n");
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Maybe this one could be promoted to an opt remark

// In case of recursion: make sure to use conservative register counts
// (i.e., specifically for VGPR/SGPR/AGPR).
switch (RIK) {
Expand Down Expand Up @@ -172,6 +181,18 @@ void MCResourceInfo::gatherResourceInfo(
const TargetMachine &TM = MF.getTarget();
MCSymbol *FnSym = TM.getSymbol(&MF.getFunction());

LLVM_DEBUG(dbgs() << "MCResUse: Gathering resource information for "
<< FnSym->getName() << '\n');
LLVM_DEBUG({
if (!FRI.Callees.empty()) {
dbgs() << "MCResUse: Callees:\n";
for (const Function *Callee : FRI.Callees) {
MCSymbol *CalleeFnSym = TM.getSymbol(&Callee->getFunction());
dbgs() << "MCResUse: " << CalleeFnSym->getName() << '\n';
}
}
});

auto SetMaxReg = [&](MCSymbol *MaxSym, int32_t numRegs,
ResourceInfoKind RIK) {
if (!FRI.HasIndirectCall) {
Expand All @@ -184,9 +205,12 @@ void MCResourceInfo::gatherResourceInfo(
const MCExpr *MaxWithLocal = AMDGPUMCExpr::createMax(
{MCConstantExpr::create(numRegs, OutContext), SymRef}, OutContext);
LocalNumSym->setVariableValue(MaxWithLocal);
LLVM_DEBUG(dbgs() << "MCResUse: " << LocalNumSym->getName()
<< ": Indirect callee within, using module maximum\n");
}
};

LLVM_DEBUG(dbgs() << "MCResUse: " << FnSym->getName() << '\n');
SetMaxReg(MaxVGPRSym, FRI.NumVGPR, RIK_NumVGPR);
SetMaxReg(MaxAGPRSym, FRI.NumAGPR, RIK_NumAGPR);
SetMaxReg(MaxSGPRSym, FRI.NumExplicitSGPR, RIK_NumSGPR);
Expand All @@ -197,9 +221,13 @@ void MCResourceInfo::gatherResourceInfo(
SmallVector<const MCExpr *, 8> ArgExprs;
MCSymbol *Sym =
getSymbol(FnSym->getName(), RIK_PrivateSegSize, OutContext, IsLocal);
if (FRI.CalleeSegmentSize)
if (FRI.CalleeSegmentSize) {
LLVM_DEBUG(dbgs() << "MCResUse: " << Sym->getName() << ": Adding "
<< FRI.CalleeSegmentSize
<< " for indirect/recursive callees within\n");
ArgExprs.push_back(
MCConstantExpr::create(FRI.CalleeSegmentSize, OutContext));
}

SmallPtrSet<const Function *, 8> Seen;
Seen.insert(&MF.getFunction());
Expand All @@ -218,12 +246,17 @@ void MCResourceInfo::gatherResourceInfo(
if (!CalleeValSym->isVariable() ||
!CalleeValSym->getVariableValue(/*isUsed=*/false)
->isSymbolUsedInExpression(Sym)) {
LLVM_DEBUG(dbgs() << "MCResUse: " << Sym->getName() << ": Adding "
<< CalleeValSym->getName() << " as callee\n");
ArgExprs.push_back(MCSymbolRefExpr::create(CalleeValSym, OutContext));
}
}
}
const MCExpr *localConstExpr =
MCConstantExpr::create(FRI.PrivateSegmentSize, OutContext);
LLVM_DEBUG(dbgs() << "MCResUse: " << Sym->getName() << ": Adding "
<< FRI.PrivateSegmentSize
<< " as function local usage\n");
if (!ArgExprs.empty()) {
const AMDGPUMCExpr *transitiveExpr =
AMDGPUMCExpr::createMax(ArgExprs, OutContext);
Expand All @@ -235,6 +268,9 @@ void MCResourceInfo::gatherResourceInfo(

auto SetToLocal = [&](int64_t LocalValue, ResourceInfoKind RIK) {
MCSymbol *Sym = getSymbol(FnSym->getName(), RIK, OutContext, IsLocal);
LLVM_DEBUG(
dbgs() << "MCResUse: " << Sym->getName() << ": Adding " << LocalValue
<< ", no further propagation as indirect callee found within\n");
Sym->setVariableValue(MCConstantExpr::create(LocalValue, OutContext));
};

Expand Down