Do not save/restore regs in ClinitCheck slow path.
The entrypoint is kSaveEverything, so the only register that
needs to be saved is the argument/return value register.
The size of the aosp_taimen-userdebug prebuilts:
- before:
arm/boot*.oat: 16811692
arm64/boot*.oat: 19801032
oat/arm64/services.odex: 20232208
- after:
arm/boot*.oat: 16798804 (-12.6KiB, -0.08%)
arm64/boot*.oat: 19804392 (+3.3KiB, +0.02%)
oat/arm64/services.odex: 20227784 (-4.3KiB, -0.02%)
Note that though there is less code, the metadata for the
arm64/boot*.oat outweighs the code size reduction because of
the register map encoding as value+shift introduced in
https://android-review.googlesource.com/695682
which it's ill-suited for kSaveEverything entrypoints. We
should reconsider that encoding.
Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Test: Pixel 2 XL boots.
Test: testrunner.py --target --optimizing
Change-Id: I5cd1deb90332a3b88a0a59d87925c557d9bff1ab
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index aabf2e0..7e3fded 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -56,6 +56,13 @@
static constexpr int kC2ConditionMask = 0x400;
+static RegisterSet OneRegInReferenceOutSaveEverythingCallerSaves() {
+ // Custom calling convention: RAX serves as both input and output.
+ RegisterSet caller_saves = RegisterSet::Empty();
+ caller_saves.Add(Location::RegisterLocation(RAX));
+ return caller_saves;
+}
+
// NOLINT on __ macro to suppress wrong warning/fix (misc-macro-parentheses) from clang-tidy.
#define __ down_cast<X86_64Assembler*>(codegen->GetAssembler())-> // NOLINT
#define QUICK_ENTRY_POINT(x) QUICK_ENTRYPOINT_OFFSET(kX86_64PointerSize, x).Int32Value()
@@ -5832,10 +5839,7 @@
if (load_kind == HLoadClass::LoadKind::kBssEntry) {
if (!kUseReadBarrier || kUseBakerReadBarrier) {
// Rely on the type resolution and/or initialization to save everything.
- // Custom calling convention: RAX serves as both input and output.
- RegisterSet caller_saves = RegisterSet::Empty();
- caller_saves.Add(Location::RegisterLocation(RAX));
- locations->SetCustomSlowPathCallerSaves(caller_saves);
+ locations->SetCustomSlowPathCallerSaves(OneRegInReferenceOutSaveEverythingCallerSaves());
} else {
// For non-Baker read barrier we have a temp-clobbering call.
}
@@ -5950,6 +5954,8 @@
if (check->HasUses()) {
locations->SetOut(Location::SameAsFirstInput());
}
+ // Rely on the type initialization to save everything we need.
+ locations->SetCustomSlowPathCallerSaves(OneRegInReferenceOutSaveEverythingCallerSaves());
}
void LocationsBuilderX86_64::VisitLoadMethodHandle(HLoadMethodHandle* load) {
@@ -6009,10 +6015,7 @@
if (load->GetLoadKind() == HLoadString::LoadKind::kBssEntry) {
if (!kUseReadBarrier || kUseBakerReadBarrier) {
// Rely on the pResolveString to save everything.
- // Custom calling convention: RAX serves as both input and output.
- RegisterSet caller_saves = RegisterSet::Empty();
- caller_saves.Add(Location::RegisterLocation(RAX));
- locations->SetCustomSlowPathCallerSaves(caller_saves);
+ locations->SetCustomSlowPathCallerSaves(OneRegInReferenceOutSaveEverythingCallerSaves());
} else {
// For non-Baker read barrier we have a temp-clobbering call.
}