[riscv64] Save kCallerSaveFpu Register in LeaveExitFrame and EnterExitFrame.

Change-Id: I0ecd8450fce35925dc00f5db65a1132deb813b59
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3483696Reviewed-by: ji qiu <qiuji@iscas.ac.cn>
Commit-Queue: ji qiu <qiuji@iscas.ac.cn>
Cr-Commit-Position: refs/heads/main@{#79299}

src/codegen/riscv64/macro-assembler-riscv64.cc

@@ -4444,12 +4444,15 @@ void MacroAssembler::EnterExitFrame(bool save_doubles, int stack_space,
   const int frame_alignment = MacroAssembler::ActivationFrameAlignment();
   if (save_doubles) {
     // The stack is already aligned to 0 modulo 8 for stores with sdc1.
-    int kNumOfSavedRegisters = FPURegister::kNumRegisters;
-    int space = kNumOfSavedRegisters * kDoubleSize;
+    int space = kNumCallerSavedFPU * kDoubleSize;
     Sub64(sp, sp, Operand(space));
-    for (int i = 0; i < kNumOfSavedRegisters; i++) {
-      FPURegister reg = FPURegister::from_code(i);
-      StoreDouble(reg, MemOperand(sp, i * kDoubleSize));
+    int count = 0;
+    for (int i = 0; i < kNumFPURegisters; i++) {
+      if (kCallerSavedFPU & (1 << i)) {
+        FPURegister reg = FPURegister::from_code(i);
+        StoreDouble(reg, MemOperand(sp, count * kDoubleSize));
+        count++;
+      }
     }
   }
 
@@ -4480,14 +4483,17 @@ void MacroAssembler::LeaveExitFrame(bool save_doubles, Register argument_count,
   BlockTrampolinePoolScope block_trampoline_pool(this);
   // Optionally restore all double registers.
   if (save_doubles) {
-    // Remember: we only need to restore every 2nd double FPU value.
-    int kNumOfSavedRegisters = FPURegister::kNumRegisters / 2;
+    // Remember: we only need to restore kCallerSavedFPU.
     Sub64(scratch, fp,
           Operand(ExitFrameConstants::kFixedFrameSizeFromFp +
-                  kNumOfSavedRegisters * kDoubleSize));
-    for (int i = 0; i < kNumOfSavedRegisters; i++) {
-      FPURegister reg = FPURegister::from_code(2 * i);
-      LoadDouble(reg, MemOperand(scratch, i * kDoubleSize));
+                  kNumCallerSavedFPU * kDoubleSize));
+    int cout = 0;
+    for (int i = 0; i < kNumFPURegisters; i++) {
+      if (kCalleeSavedFPU & (1 << i)) {
+        FPURegister reg = FPURegister::from_code(i);
+        LoadDouble(reg, MemOperand(scratch, cout * kDoubleSize));
+        cout++;
+      }
     }
   }
 

src/codegen/riscv64/macro-assembler-riscv64.h

@@ -1107,7 +1107,7 @@ class V8_EXPORT_PRIVATE MacroAssembler : public TurboAssembler {
 
   // Enter exit frame.
   // argc - argument count to be dropped by LeaveExitFrame.
-  // save_doubles - saves FPU registers on stack, currently disabled.
+  // save_doubles - saves FPU registers on stack.
   // stack_space - extra stack space.
   void EnterExitFrame(bool save_doubles, int stack_space = 0,
                       StackFrame::Type frame_type = StackFrame::EXIT);

src/codegen/riscv64/register-riscv64.h

@@ -121,7 +121,7 @@ const RegList kCalleeSavedFPU = 1 << 8 |   // fs0
                                 1 << 26 |  // fs10
                                 1 << 27;   // fs11
 
-const int kNumCalleeSavedFPU = 12;
+const int kNumCalleeSavedFPU = NumRegs(kCalleeSavedFPU);
 
 const RegList kCallerSavedFPU = 1 << 0 |   // ft0
                                 1 << 1 |   // ft1
@@ -144,6 +144,8 @@ const RegList kCallerSavedFPU = 1 << 0 |   // ft0
                                 1 << 30 |  // ft10
                                 1 << 31;   // ft11
 
+const int kNumCallerSavedFPU = NumRegs(kCallerSavedFPU);
+
 // Number of registers for which space is reserved in safepoints. Must be a
 // multiple of 8.
 const int kNumSafepointRegisters = 32;