aix, builtins: Embedded builtins support on Aix

Bug: v8:8043
Change-Id: Iff786eccd2dcb63e46e331b096d91a6ddb13f851
Reviewed-on: https://chromium-review.googlesource.com/c/1351129
Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#57913}

BUILD.gn

@@ -86,8 +86,7 @@ declare_args() {
   v8_enable_fast_mksnapshot = false
 
   # Enable embedded builtins.
-  # TODO(v8:8043): Support aix.
-  v8_enable_embedded_builtins = !is_aix
+  v8_enable_embedded_builtins = true
 
   # Build-time flag for enabling nojit mode.
   # TODO(v8:7777): Remove the build-time flag once the --jitless runtime flag

src/ppc/code-stubs-ppc.cc

@@ -180,6 +180,13 @@ void DirectCEntryStub::Generate(MacroAssembler* masm) {
   // GC safe. The RegExp backend also relies on this.
   __ mflr(r0);
   __ StoreP(r0, MemOperand(sp, kStackFrameExtraParamSlot * kPointerSize));
+
+  if (ABI_USES_FUNCTION_DESCRIPTORS && FLAG_embedded_builtins) {
+    // AIX/PPC64BE Linux use a function descriptor;
+    __ LoadP(ToRegister(ABI_TOC_REGISTER), MemOperand(ip, kPointerSize));
+    __ LoadP(ip, MemOperand(ip, 0));  // Instruction address
+  }
+
   __ Call(ip);  // Call the C++ function.
   __ LoadP(r0, MemOperand(sp, kStackFrameExtraParamSlot * kPointerSize));
   __ mtlr(r0);
@@ -201,7 +208,7 @@ void DirectCEntryStub::GenerateCall(MacroAssembler* masm, Register target) {
       return;
     }
   }
-  if (ABI_USES_FUNCTION_DESCRIPTORS) {
+  if (ABI_USES_FUNCTION_DESCRIPTORS && !FLAG_embedded_builtins) {
     // AIX/PPC64BE Linux use a function descriptor.
     __ LoadP(ToRegister(ABI_TOC_REGISTER), MemOperand(target, kPointerSize));
     __ LoadP(ip, MemOperand(target, 0));  // Instruction address

src/snapshot/embedded-file-writer.cc

@@ -54,6 +54,17 @@ const char* DirectiveAsString(DataDirective directive) {
     default:
       UNREACHABLE();
   }
+#elif defined(V8_OS_AIX)
+  switch (directive) {
+    case kByte:
+      return ".byte";
+    case kLong:
+      return ".long";
+    case kQuad:
+      return ".llong";
+    default:
+      UNREACHABLE();
+  }
 #else
   switch (directive) {
     case kByte:
@@ -152,16 +163,11 @@ int PlatformDependentEmbeddedFileWriter::IndentedDataDirective(
 
 #elif defined(V8_OS_AIX)
 
-// TODO(aix): Update custom logic previously contained in section header macros.
-// See
-// https://cs.chromium.org/chromium/src/v8/src/snapshot/macros.h?l=81&rcl=31b2546b348e864539ade15897eac971b3c0e402
-
 void PlatformDependentEmbeddedFileWriter::SectionText() {
   fprintf(fp_, ".csect .text[PR]\n");
 }
 
 void PlatformDependentEmbeddedFileWriter::SectionData() {
-  // TODO(aix): Confirm and update if needed.
   fprintf(fp_, ".csect .data[RW]\n");
 }
 
@@ -172,15 +178,16 @@ void PlatformDependentEmbeddedFileWriter::SectionRoData() {
 void PlatformDependentEmbeddedFileWriter::DeclareUint32(const char* name,
                                                         uint32_t value) {
   DeclareSymbolGlobal(name);
-  DeclareLabel(name);
+  fprintf(fp_, ".align 2\n");
+  fprintf(fp_, "%s:\n", name);
   IndentedDataDirective(kLong);
-  fprintf(fp_, "%d", value);
+  fprintf(fp_, "%d\n", value);
   Newline();
 }
 
 void PlatformDependentEmbeddedFileWriter::DeclarePointerToSymbol(
     const char* name, const char* target) {
-  DeclareSymbolGlobal(name);
+  AlignToCodeAlignment();
   DeclareLabel(name);
   fprintf(fp_, "  %s %s\n", DirectiveAsString(PointerSizeDirective()), target);
   Newline();
@@ -192,7 +199,7 @@ void PlatformDependentEmbeddedFileWriter::DeclareSymbolGlobal(
 }
 
 void PlatformDependentEmbeddedFileWriter::AlignToCodeAlignment() {
-  fprintf(fp_, ".balign 32\n");
+  fprintf(fp_, ".align 5\n");
 }
 
 void PlatformDependentEmbeddedFileWriter::Comment(const char* string) {
@@ -200,12 +207,19 @@ void PlatformDependentEmbeddedFileWriter::Comment(const char* string) {
 }
 
 void PlatformDependentEmbeddedFileWriter::DeclareLabel(const char* name) {
+  DeclareSymbolGlobal(name);
   fprintf(fp_, "%s:\n", name);
 }
 
 void PlatformDependentEmbeddedFileWriter::DeclareFunctionBegin(
     const char* name) {
-  DeclareLabel(name);
+  Newline();
+  DeclareSymbolGlobal(name);
+  fprintf(fp_, ".csect %s[DS]\n", name); // function descriptor
+  fprintf(fp_, "%s:\n", name);
+  fprintf(fp_, ".llong .%s, 0, 0\n", name);
+  SectionText();
+  fprintf(fp_, ".%s:\n", name);
 }
 
 void PlatformDependentEmbeddedFileWriter::DeclareFunctionEnd(const char* name) {

src/snapshot/embedded-file-writer.h

@@ -205,7 +205,7 @@ class EmbeddedFileWriter {
 #define V8_COMPILER_IS_MSVC
 #endif
 
-#ifdef V8_COMPILER_IS_MSVC
+#if defined(V8_COMPILER_IS_MSVC) || defined(V8_OS_AIX)
   // Windows MASM doesn't have an .octa directive, use QWORDs instead.
   // Note: MASM *really* does not like large data streams. It takes over 5
   // minutes to assemble the ~350K lines of embedded.S produced when using
@@ -213,6 +213,8 @@ class EmbeddedFileWriter {
   // reduces assembly time to ~40 seconds. Still terrible, but much better
   // than before. See also: https://crbug.com/v8/8475.
 
+  // GCC MASM on Aix doesn't have an .octa directive, use .llong instead.
+
   static constexpr DataDirective kByteChunkDirective = kQuad;
   static constexpr int kByteChunkSize = 8;
 
@@ -221,7 +223,7 @@ class EmbeddedFileWriter {
     const uint64_t* quad_ptr = reinterpret_cast<const uint64_t*>(data);
     return current_line_length + w->HexLiteral(*quad_ptr);
   }
-#else  // V8_COMPILER_IS_MSVC
+#else  // defined(V8_COMPILER_IS_MSVC) || defined(V8_OS_AIX)
   static constexpr DataDirective kByteChunkDirective = kOcta;
   static constexpr int kByteChunkSize = 16;
 
@@ -246,7 +248,7 @@ class EmbeddedFileWriter {
     }
     return current_line_length;
   }
-#endif  // V8_COMPILER_IS_MSVC
+#endif  // defined(V8_COMPILER_IS_MSVC) || defined(V8_OS_AIX)
 #undef V8_COMPILER_IS_MSVC
 
   static int WriteDirectiveOrSeparator(PlatformDependentEmbeddedFileWriter* w,