8293999: [JVMCI] need support for aligned constants in generated code larger than 8 bytes

Reviewed-by: dlong, dnsimon

src/hotspot/cpu/arm/arm.ad

@@ -236,8 +236,9 @@ void MachConstantBaseNode::emit(CodeBuffer& cbuf, PhaseRegAlloc* ra_) const {
 
   Register r = as_Register(ra_->get_encode(this));
   CodeSection* consts_section = __ code()->consts();
+  CodeSection* insts_section = __ code()->insts();
   // constants section size is aligned according to the align_at_start settings of the next section
-  int consts_size = CodeSection::align_at_start(consts_section->size(), CodeBuffer::SECT_INSTS);
+  int consts_size = insts_section->align_at_start(consts_section->size());
   assert(constant_table.size() == consts_size, "must be: %d == %d", constant_table.size(), consts_size);
 
   // Materialize the constant table base.

src/hotspot/share/asm/codeBuffer.cpp

@@ -422,6 +422,21 @@ void CodeSection::expand_locs(int new_capacity) {
   }
 }
 
+int CodeSection::alignment() const {
+  if (_index == CodeBuffer::SECT_CONSTS) {
+    // CodeBuffer controls the alignment of the constants section
+    return _outer->_const_section_alignment;
+  }
+  if (_index == CodeBuffer::SECT_INSTS) {
+    return (int) CodeEntryAlignment;
+  }
+  if (_index == CodeBuffer::SECT_STUBS) {
+    // CodeBuffer installer expects sections to be HeapWordSize aligned
+    return HeapWordSize;
+  }
+  ShouldNotReachHere();
+  return 0;
+}
 
 /// Support for emitting the code to its final location.
 /// The pattern is the same for all functions.

src/hotspot/share/asm/codeBuffer.hpp

@@ -27,6 +27,7 @@
 
 #include "code/oopRecorder.hpp"
 #include "code/relocInfo.hpp"
+#include "compiler/compiler_globals.hpp"
 #include "utilities/align.hpp"
 #include "utilities/debug.hpp"
 #include "utilities/growableArray.hpp"
@@ -256,18 +257,13 @@ class CodeSection {
   void relocate(address at, RelocationHolder const& rspec, int format = 0);
   void relocate(address at,    relocInfo::relocType rtype, int format = 0, jint method_index = 0);
 
-  static int alignment(int section);
-  int alignment() { return alignment(_index); }
+  int alignment() const;
 
   // Slop between sections, used only when allocating temporary BufferBlob buffers.
   static csize_t end_slop()         { return MAX2((int)sizeof(jdouble), (int)CodeEntryAlignment); }
 
-  static csize_t align_at_start(csize_t off, int section) {
-    return (csize_t) align_up(off, alignment(section));
-  }
-
   csize_t align_at_start(csize_t off) const {
-    return align_at_start(off, _index);
+    return (csize_t) align_up(off, alignment());
   }
 
   // Ensure there's enough space left in the current section.
@@ -431,6 +427,8 @@ class CodeBuffer: public StackObj DEBUG_ONLY(COMMA private Scrubber) {
   SharedTrampolineRequests*   _shared_trampoline_requests;     // used to collect requests for shared trampolines
   bool         _finalize_stubs; // Indicate if we need to finalize stubs to make CodeBuffer final.
 
+  int          _const_section_alignment;
+
 #ifndef PRODUCT
   AsmRemarks   _asm_remarks;
   DbgStrings   _dbg_strings;
@@ -456,6 +454,10 @@ class CodeBuffer: public StackObj DEBUG_ONLY(COMMA private Scrubber) {
     _insts.initialize_outer(this,  SECT_INSTS);
     _stubs.initialize_outer(this,  SECT_STUBS);
 
+    // Default is to align on 8 bytes. A compiler can change this
+    // if larger alignment (e.g., 32-byte vector masks) is required.
+    _const_section_alignment = (int) sizeof(jdouble);
+
 #ifndef PRODUCT
     _decode_begin    = NULL;
     // Collect block comments, but restrict collection to cases where a disassembly is output.
@@ -709,6 +711,10 @@ class CodeBuffer: public StackObj DEBUG_ONLY(COMMA private Scrubber) {
   // Request for a shared stub to the interpreter
   void shared_stub_to_interp_for(ciMethod* callee, csize_t call_offset);
 
+  void set_const_section_alignment(int align) {
+    _const_section_alignment = align_up(align, HeapWordSize);
+  }
+
 #ifndef PRODUCT
  public:
   // Printing / Decoding
@@ -746,19 +752,4 @@ inline bool CodeSection::maybe_expand_to_ensure_remaining(csize_t amount) {
   return false;
 }
 
-inline int CodeSection::alignment(int section) {
-  if (section == CodeBuffer::SECT_CONSTS) {
-    return (int) sizeof(jdouble);
-  }
-  if (section == CodeBuffer::SECT_INSTS) {
-    return (int) CodeEntryAlignment;
-  }
-  if (section == CodeBuffer::SECT_STUBS) {
-    // CodeBuffer installer expects sections to be HeapWordSize aligned
-    return HeapWordSize;
-  }
-  ShouldNotReachHere();
-  return 0;
-}
-
 #endif // SHARE_ASM_CODEBUFFER_HPP

src/hotspot/share/jvmci/jvmciCodeInstaller.cpp

@@ -687,7 +687,7 @@ JVMCI::CodeInstallResult CodeInstaller::install(JVMCICompiler* compiler,
   _instructions = buffer.insts();
   _constants = buffer.consts();
 
-  initialize_fields(stream, code_flags, method, JVMCI_CHECK_OK);
+  initialize_fields(stream, code_flags, method, buffer, JVMCI_CHECK_OK);
   JVMCI::CodeInstallResult result = initialize_buffer(compiled_code, buffer, stream, code_flags, JVMCI_CHECK_OK);
 
   u4 available = stream->available();
@@ -770,7 +770,7 @@ JVMCI::CodeInstallResult CodeInstaller::install(JVMCICompiler* compiler,
   return result;
 }
 
-void CodeInstaller::initialize_fields(HotSpotCompiledCodeStream* stream, u1 code_flags, methodHandle& method, JVMCI_TRAPS) {
+void CodeInstaller::initialize_fields(HotSpotCompiledCodeStream* stream, u1 code_flags, methodHandle& method, CodeBuffer& buffer, JVMCI_TRAPS) {
   if (!method.is_null()) {
     _parameter_count = method->size_of_parameters();
     JVMCI_event_2("installing code for %s", method->name_and_sig_as_C_string());
@@ -797,6 +797,7 @@ void CodeInstaller::initialize_fields(HotSpotCompiledCodeStream* stream, u1 code
   // Pre-calculate the constants section size.  This is required for PC-relative addressing.
   u4 data_section_size = stream->read_u4("dataSectionSize");
   u1 data_section_alignment = stream->read_u1("dataSectionAlignment");
+  buffer.set_const_section_alignment(data_section_alignment);
   if ((_constants->alignment() % data_section_alignment) != 0) {
     JVMCI_ERROR("invalid data section alignment: %d [constants alignment: %d]%s",
         data_section_alignment, _constants->alignment(), stream->context());
@@ -851,8 +852,8 @@ JVMCI::CodeInstallResult CodeInstaller::initialize_buffer(JVMCIObject compiled_c
   assert((CodeBuffer::SECT_INSTS == CodeBuffer::SECT_STUBS - 1) &&
          (CodeBuffer::SECT_CONSTS == CodeBuffer::SECT_INSTS - 1), "sections order: consts, insts, stubs");
   // buffer content: [constants + code_align] + [code + stubs_align] + [stubs]
-  int total_size = align_up(_constants_size, CodeSection::alignment(CodeBuffer::SECT_INSTS)) +
-                   align_up(_code_size, CodeSection::alignment(CodeBuffer::SECT_STUBS)) +
+  int total_size = align_up(_constants_size, buffer.insts()->alignment()) +
+                   align_up(_code_size, buffer.stubs()->alignment()) +
                    stubs_size;
 
   if (total_size > JVMCINMethodSizeLimit) {

src/hotspot/share/jvmci/jvmciCodeInstaller.hpp

@@ -361,7 +361,7 @@ protected:
   GrowableArray<MonitorValue*>* read_monitor_values(HotSpotCompiledCodeStream* stream, u1 frame_flags, JVMCI_TRAPS);
 
   // extract the fields of the HotSpotCompiledCode
-  void initialize_fields(HotSpotCompiledCodeStream* stream, u1 code_flags, methodHandle& method, JVMCI_TRAPS);
+  void initialize_fields(HotSpotCompiledCodeStream* stream, u1 code_flags, methodHandle& method, CodeBuffer& buffer, JVMCI_TRAPS);
   void initialize_dependencies(HotSpotCompiledCodeStream* stream, u1 code_flags, OopRecorder* oop_recorder, JVMCI_TRAPS);
 
   int estimate_stubs_size(HotSpotCompiledCodeStream* stream, JVMCI_TRAPS);