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[vm, simarm64] Extract CalleeRegisterVerifier class

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Closes https://github.com/dart-lang/sdk/pull/63012

GitOrigin-RevId: 56b29e0480f66e41ddd15e24249a5be75aed13ca
Change-Id: I55ed703a366aefd3b273acd74a6c99c91ed38759
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/491682
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
This commit is contained in:
Eric Seidel
2026-05-13 11:42:35 -07:00
committed by dart-scoped@luci-project-accounts.iam.gserviceaccount.com
parent d65783ef59
commit a6a403c0b9
1 changed files with 52 additions and 37 deletions
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runtime/vm/simulator_arm64.cc
+52 -37
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@@ -4019,6 +4019,54 @@ void Simulator::ExecuteTrace() {
}
}
// Verifies that callee-saved registers are preserved across Dart execution.
// On construction, saves and overwrites callee-saved registers with a known
// value. On destruction, asserts that the known value is still present and
// restores the original values.
class CalleeRegisterVerifier {
public:
explicit CalleeRegisterVerifier(Simulator* sim)
: sim_(sim),
callee_saved_value_(
bit_cast<int64_t, double>(static_cast<double>(sim->get_icount()))) {
for (int i = kAbiFirstPreservedCpuReg; i <= kAbiLastPreservedCpuReg; i++) {
const Register r = static_cast<Register>(i);
preserved_cpu_[i - kAbiFirstPreservedCpuReg] = sim->get_register(r);
sim->set_register(nullptr, r, callee_saved_value_);
}
// Only the bottom half of the V registers must be preserved.
for (int i = kAbiFirstPreservedFpuReg; i <= kAbiLastPreservedFpuReg; i++) {
const VRegister r = static_cast<VRegister>(i);
preserved_fpu_[i - kAbiFirstPreservedFpuReg] = sim->get_vregisterd(r, 0);
sim->set_vregisterd(r, 0, callee_saved_value_);
sim->set_vregisterd(r, 1, 0);
}
}
~CalleeRegisterVerifier() {
for (int i = kAbiFirstPreservedCpuReg; i <= kAbiLastPreservedCpuReg; i++) {
const Register r = static_cast<Register>(i);
ASSERT(callee_saved_value_ == sim_->get_register(r));
sim_->set_register(nullptr, r,
preserved_cpu_[i - kAbiFirstPreservedCpuReg]);
}
for (int i = kAbiFirstPreservedFpuReg; i <= kAbiLastPreservedFpuReg; i++) {
const VRegister r = static_cast<VRegister>(i);
ASSERT(callee_saved_value_ == sim_->get_vregisterd(r, 0));
sim_->set_vregisterd(r, 0, preserved_fpu_[i - kAbiFirstPreservedFpuReg]);
sim_->set_vregisterd(r, 1, 0);
}
}
private:
Simulator* const sim_;
const int64_t callee_saved_value_;
int64_t preserved_cpu_[kAbiPreservedCpuRegCount];
int64_t preserved_fpu_[kAbiPreservedFpuRegCount];
DISALLOW_COPY_AND_ASSIGN(CalleeRegisterVerifier);
};
int64_t Simulator::Call(int64_t entry,
int64_t parameter0,
int64_t parameter1,
@@ -4061,43 +4109,10 @@ int64_t Simulator::Call(int64_t entry,
// the LR the simulation stops when returning to this call point.
set_register(nullptr, LR, kEndSimulatingPC);
// Remember the values of callee-saved registers, and set them up with a
// known value so that we are able to check that they are preserved
// properly across Dart execution.
int64_t preserved_vals[kAbiPreservedCpuRegCount];
const double dicount = static_cast<double>(icount_);
const int64_t callee_saved_value = bit_cast<int64_t, double>(dicount);
for (int i = kAbiFirstPreservedCpuReg; i <= kAbiLastPreservedCpuReg; i++) {
const Register r = static_cast<Register>(i);
preserved_vals[i - kAbiFirstPreservedCpuReg] = get_register(r);
set_register(nullptr, r, callee_saved_value);
}
// Only the bottom half of the V registers must be preserved.
int64_t preserved_dvals[kAbiPreservedFpuRegCount];
for (int i = kAbiFirstPreservedFpuReg; i <= kAbiLastPreservedFpuReg; i++) {
const VRegister r = static_cast<VRegister>(i);
preserved_dvals[i - kAbiFirstPreservedFpuReg] = get_vregisterd(r, 0);
set_vregisterd(r, 0, callee_saved_value);
set_vregisterd(r, 1, 0);
}
// Start the simulation.
Execute();
// Check that the callee-saved registers have been preserved,
// and restore them with the original value.
for (int i = kAbiFirstPreservedCpuReg; i <= kAbiLastPreservedCpuReg; i++) {
const Register r = static_cast<Register>(i);
ASSERT(callee_saved_value == get_register(r));
set_register(nullptr, r, preserved_vals[i - kAbiFirstPreservedCpuReg]);
}
for (int i = kAbiFirstPreservedFpuReg; i <= kAbiLastPreservedFpuReg; i++) {
const VRegister r = static_cast<VRegister>(i);
ASSERT(callee_saved_value == get_vregisterd(r, 0));
set_vregisterd(r, 0, preserved_dvals[i - kAbiFirstPreservedFpuReg]);
set_vregisterd(r, 1, 0);
{
// Verify callee-saved registers are preserved across Dart execution.
CalleeRegisterVerifier callee_saved(this);
Execute();
}
// Restore the SP register and return R0.