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8358655: AArch64: Simplify Interpreter::profile_taken_branch #25906

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8358655: AArch64: Simplify Interpreter::profile_taken_branch #25906

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ae31d0f
8358655: AArch64: Simplify Interpreter::profile_taken_branch
chadrako Jun 19, 2025
c2d5ef3
Remove r1 save
chadrako Jun 20, 2025
29cd004
Merge remote-tracking branch 'origin/master' into JDK-8358655-profile…
chadrako Jun 23, 2025
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23 changes: 4 additions & 19 deletions src/hotspot/cpu/aarch64/interp_masm_aarch64.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1016,31 +1016,16 @@ void InterpreterMacroAssembler::update_mdp_for_ret(Register return_bci) {
}


void InterpreterMacroAssembler::profile_taken_branch(Register mdp,
Register bumped_count) {
void InterpreterMacroAssembler::profile_taken_branch(Register mdp) {
if (ProfileInterpreter) {
Label profile_continue;

// If no method data exists, go to profile_continue.
// Otherwise, assign to mdp
test_method_data_pointer(mdp, profile_continue);

// We are taking a branch. Increment the taken count.
// We inline increment_mdp_data_at to return bumped_count in a register
//increment_mdp_data_at(mdp, in_bytes(JumpData::taken_offset()));
Address data(mdp, in_bytes(JumpData::taken_offset()));
ldr(bumped_count, data);
assert(DataLayout::counter_increment == 1,
"flow-free idiom only works with 1");
// Intel does this to catch overflow
// addptr(bumped_count, DataLayout::counter_increment);
// sbbptr(bumped_count, 0);
// so we do this
adds(bumped_count, bumped_count, DataLayout::counter_increment);
Label L;
br(Assembler::CS, L); // skip store if counter overflow
str(bumped_count, data);
bind(L);
increment_mdp_data_at(mdp, in_bytes(JumpData::taken_offset()));

// The method data pointer needs to be updated to reflect the new target.
update_mdp_by_offset(mdp, in_bytes(JumpData::displacement_offset()));
bind(profile_continue);
Expand All @@ -1055,7 +1040,7 @@ void InterpreterMacroAssembler::profile_not_taken_branch(Register mdp) {
// If no method data exists, go to profile_continue.
test_method_data_pointer(mdp, profile_continue);

// We are taking a branch. Increment the not taken count.
// We are not taking a branch. Increment the not taken count.
increment_mdp_data_at(mdp, in_bytes(BranchData::not_taken_offset()));

// The method data pointer needs to be updated to correspond to
Expand Down
2 changes: 1 addition & 1 deletion src/hotspot/cpu/aarch64/interp_masm_aarch64.hpp
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Expand Up @@ -276,7 +276,7 @@ class InterpreterMacroAssembler: public MacroAssembler {
// narrow int return value
void narrow(Register result);

void profile_taken_branch(Register mdp, Register bumped_count);
void profile_taken_branch(Register mdp);
void profile_not_taken_branch(Register mdp);
void profile_call(Register mdp);
void profile_final_call(Register mdp);
Expand Down
5 changes: 1 addition & 4 deletions src/hotspot/cpu/aarch64/templateTable_aarch64.cpp
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Expand Up @@ -1759,7 +1759,7 @@ void TemplateTable::float_cmp(bool is_float, int unordered_result)

void TemplateTable::branch(bool is_jsr, bool is_wide)
{
__ profile_taken_branch(r0, r1);
__ profile_taken_branch(r0);
const ByteSize be_offset = MethodCounters::backedge_counter_offset() +
InvocationCounter::counter_offset();
const ByteSize inv_offset = MethodCounters::invocation_counter_offset() +
Expand Down Expand Up @@ -1809,7 +1809,6 @@ void TemplateTable::branch(bool is_jsr, bool is_wide)
if (UseLoopCounter) {
// increment backedge counter for backward branches
// r0: MDO
// w1: MDO bumped taken-count
// r2: target offset
__ cmp(r2, zr);
__ br(Assembler::GT, dispatch); // count only if backward branch
Expand All @@ -1820,12 +1819,10 @@ void TemplateTable::branch(bool is_jsr, bool is_wide)
__ ldr(rscratch1, Address(rmethod, Method::method_counters_offset()));
__ cbnz(rscratch1, has_counters);
__ push(r0);
__ push(r1);
__ push(r2);
__ call_VM(noreg, CAST_FROM_FN_PTR(address,
InterpreterRuntime::build_method_counters), rmethod);
__ pop(r2);
__ pop(r1);
__ pop(r0);
__ ldr(rscratch1, Address(rmethod, Method::method_counters_offset()));
__ cbz(rscratch1, dispatch); // No MethodCounters allocated, OutOfMemory
Expand Down