aix: add required changes to build with clang

abmusse · V8 LUCI CQ · commit fcf8b990c73c · 2025-12-17T03:15:37.000-08:00
Change-Id: Icc78c58831306aa2f227843b0b4ec2321585fa64 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/7107287 Reviewed-by: Toon Verwaest <verwaest@chromium.org> Commit-Queue: Clemens Backes <clemensb@chromium.org> Reviewed-by: Leszek Swirski <leszeks@chromium.org> Cr-Commit-Position: refs/heads/main@{#104364}
diff --git a/BUILD.gn b/BUILD.gn
@@ -1601,7 +1601,7 @@ config("toolchain") {
   if (v8_current_cpu == "ppc64") {
     defines += [ "V8_TARGET_ARCH_PPC64" ]
     cflags += [ "-ffp-contract=off" ]
-    if (current_os == "aix") {
+    if (current_os == "aix" && !is_clang) {
       cflags += [
         # Work around AIX ceil, trunc and round oddities.
         "-mcpu=power5+",
diff --git a/src/builtins/ppc/builtins-ppc.cc b/src/builtins/ppc/builtins-ppc.cc
@@ -4135,6 +4135,19 @@ void Builtins::Generate_CEntry(MacroAssembler* masm, int result_size,
 
   // If return value is on the stack, pop it to registers.
   if (needs_return_buffer) {
+    Label done;
+    if (switch_to_central_stack) {
+      Label no_stack_change;
+      __ CmpU64(kOldSPRegister, Operand(0), r0);
+      __ beq(&no_stack_change);
+      __ addi(r3, kOldSPRegister,
+              Operand((kStackFrameExtraParamSlot + 1) * kSystemPointerSize));
+      __ b(&done);
+      __ bind(&no_stack_change);
+    }
+    __ addi(r3, sp,
+            Operand((kStackFrameExtraParamSlot + 1) * kSystemPointerSize));
+    __ bind(&done);
     __ LoadU64(r4, MemOperand(r3, kSystemPointerSize));
     __ LoadU64(r3, MemOperand(r3));
   }
diff --git a/src/compiler/turboshaft/operations.h b/src/compiler/turboshaft/operations.h
@@ -528,7 +528,7 @@ class InputsRepFactory {
   };
 };
 
-struct EffectDimensions {
+struct __attribute__((packed)) EffectDimensions {
   // Produced by loads, consumed by operations that should not move before loads
   // because they change memory.
   bool load_heap_memory : 1;
@@ -623,7 +623,7 @@ static_assert(sizeof(EffectDimensions) == sizeof(EffectDimensions::Bits));
 // they become more restricted in their movement. Note that calls are not the
 // most side-effectful operations, as they do not leave the heap in an
 // inconsistent state, so they do not need to be marked as raw heap access.
-struct OpEffects {
+struct __attribute__((packed)) OpEffects {
   EffectDimensions produces;
   EffectDimensions consumes;
 
@@ -2902,7 +2902,7 @@ struct ConstantOp : FixedArityOperationT<0, ConstantOp> {
 // When result_rep is RegisterRepresentation::Compressed(), then the load does
 // not decompress the value.
 struct LoadOp : OperationT<LoadOp> {
-  struct Kind {
+  struct __attribute__((packed)) Kind {
     // The `base` input is a tagged pointer to a HeapObject.
     bool tagged_base : 1;
     // The effective address might be unaligned. This is only set to true if
diff --git a/src/execution/simulator.h b/src/execution/simulator.h
@@ -199,13 +199,17 @@ class GeneratedCode {
     return fn(args...);
 #else
     // AIX ABI requires function descriptors (FD).  Artificially create a pseudo
-    // FD to ensure correct dispatch to generated code.  The 'volatile'
-    // declaration is required to avoid the compiler from not observing the
-    // alias of the pseudo FD to the function pointer, and hence, optimizing the
-    // pseudo FD declaration/initialization away.
-    volatile Address function_desc[] = {reinterpret_cast<Address>(fn_ptr_), 0,
-                                        0};
-    Signature* fn = reinterpret_cast<Signature*>(function_desc);
+    // FD to ensure correct dispatch to generated code.
+    void* function_desc[3];
+    Signature* fn;
+    asm("std %1, 0(%2)\n\t"
+        "li 0, 0\n\t"
+        "std 0, 8(%2)\n\t"
+        "std 0, 16(%2)\n\t"
+        "mr %0, %2\n\t"
+        : "=r"(fn)
+        : "r"(fn_ptr_), "r"(function_desc)
+        : "memory", "0");
     return fn(args...);
 #endif  // V8_OS_ZOS
 #else
diff --git a/src/trap-handler/handler-shared.cc b/src/trap-handler/handler-shared.cc
@@ -24,7 +24,11 @@ namespace v8 {
 namespace internal {
 namespace trap_handler {
 
+#if defined(V8_OS_AIX)
+__thread bool TrapHandlerGuard::is_active_ = 0;
+#else
 thread_local bool TrapHandlerGuard::is_active_ = 0;
+#endif
 
 size_t gNumCodeObjects = 0;
 CodeProtectionInfoListEntry* gCodeObjects = nullptr;
