ppc64: fix c linkage issue on c to wasm entry

Drive-by: also cleanup ppc 32-bit support

R=joransiu@ca.ibm.com

Change-Id: I0596405ae59a0f18db7eb0f480944b8530a31113
Reviewed-on: https://chromium-review.googlesource.com/c/1262936Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#56419}

src/compiler/c-linkage.cc

@@ -99,10 +99,15 @@ namespace {
 #define CALLEE_SAVE_FP_REGISTERS \
   f20.bit() | f22.bit() | f24.bit() | f26.bit() | f28.bit() | f30.bit()
 
-#elif V8_TARGET_ARCH_PPC || V8_TARGET_ARCH_PPC64
+#elif V8_TARGET_ARCH_PPC64
 // ===========================================================================
 // == ppc & ppc64 ============================================================
 // ===========================================================================
+#ifdef V8_TARGET_LITTLE_ENDIAN  // ppc64le linux
+#define STACK_SHADOW_WORDS 12
+#else  // AIX
+#define STACK_SHADOW_WORDS 14
+#endif
 #define PARAM_REGISTERS r3, r4, r5, r6, r7, r8, r9, r10
 #define CALLEE_SAVE_REGISTERS                                                 \
   r14.bit() | r15.bit() | r16.bit() | r17.bit() | r18.bit() | r19.bit() |     \

src/compiler/ppc/instruction-selector-ppc.cc

@@ -1866,6 +1866,7 @@ void InstructionSelector::EmitPrepareArguments(
     // Poke any stack arguments.
     int slot = kStackFrameExtraParamSlot;
     for (PushParameter input : (*arguments)) {
+      if (input.node == nullptr) continue;
       Emit(kPPC_StoreToStackSlot, g.NoOutput(), g.UseRegister(input.node),
            g.TempImmediate(slot));
       ++slot;

src/ppc/assembler-ppc.h

@@ -217,7 +217,7 @@ const int kNumSafepointRegisters = 32;
 // The following constants describe the stack frame linkage area as
 // defined by the ABI.  Note that kNumRequiredStackFrameSlots must
 // satisfy alignment requirements (rounding up if required).
-#if V8_TARGET_ARCH_PPC64 && V8_TARGET_LITTLE_ENDIAN
+#if V8_TARGET_ARCH_PPC64 && V8_TARGET_LITTLE_ENDIAN  // ppc64le linux
 // [0] back chain
 // [1] condition register save area
 // [2] link register save area
@@ -230,7 +230,7 @@ const int kNumSafepointRegisters = 32;
 const int kNumRequiredStackFrameSlots = 12;
 const int kStackFrameLRSlot = 2;
 const int kStackFrameExtraParamSlot = 12;
-#elif V8_OS_AIX || V8_TARGET_ARCH_PPC64
+#else  // AIX
 // [0] back chain
 // [1] condition register save area
 // [2] link register save area
@@ -242,21 +242,9 @@ const int kStackFrameExtraParamSlot = 12;
 // [13] Parameter8 save area
 // [14] Parameter9 slot (if necessary)
 // ...
-#if V8_TARGET_ARCH_PPC64
 const int kNumRequiredStackFrameSlots = 14;
-#else
-const int kNumRequiredStackFrameSlots = 16;
-#endif
 const int kStackFrameLRSlot = 2;
 const int kStackFrameExtraParamSlot = 14;
-#else
-// [0] back chain
-// [1] link register save area
-// [2] Parameter9 slot (if necessary)
-// ...
-const int kNumRequiredStackFrameSlots = 4;
-const int kStackFrameLRSlot = 1;
-const int kStackFrameExtraParamSlot = 2;
 #endif
 
 // Define the list of registers actually saved at safepoints.