RFR: 8291003: ARM32: constant_table.size assertion

[Aleksey Shipilev]

On Thu, 28 Jul 2022 08:24:22 GMT, Boris Ulasevich <bulasevich at openjdk.org> wrote:

> This change fixes assertion condition as per the recent [JDK-8287373](https://bugs.openjdk.org/browse/JDK-8287373) change: the size of constants section is aligned up according to the settings of the next section (instructions section).

This is equivalent to the following, right?


  int consts_size = consts_section->align_at_start(consts_section->size(), CodeBuffer::SECT_INSTS);


In fact, we can make it better by doing e.g.:


diff --git a/src/hotspot/cpu/arm/arm.ad b/src/hotspot/cpu/arm/arm.ad
index a99d8599cd3..c8e4b482778 100644
--- a/src/hotspot/cpu/arm/arm.ad
+++ b/src/hotspot/cpu/arm/arm.ad
@@ -236,7 +236,8 @@ void MachConstantBaseNode::emit(CodeBuffer& cbuf, PhaseRegAlloc* ra_) const {
 
   Register r = as_Register(ra_->get_encode(this));
   CodeSection* consts_section = __ code()->consts();
-  int consts_size = consts_section->align_at_start(consts_section->size());
+  // 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);
   assert(constant_table.size() == consts_size, "must be: %d == %d", constant_table.size(), consts_size);
 
   // Materialize the constant table base.
diff --git a/src/hotspot/share/asm/codeBuffer.hpp b/src/hotspot/share/asm/codeBuffer.hpp
index e96f9c07e76..4cad3b4d30e 100644
--- a/src/hotspot/share/asm/codeBuffer.hpp
+++ b/src/hotspot/share/asm/codeBuffer.hpp
@@ -261,12 +261,12 @@ class CodeSection {
   // Slop between sections, used only when allocating temporary BufferBlob buffers.
   static csize_t end_slop()         { return MAX2((int)sizeof(jdouble), (int)CodeEntryAlignment); }
 
-  csize_t align_at_start(csize_t off, int section) const {
+  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 (csize_t) align_up(off, alignment(_index));
+    return align_at_start(off, _index);
   }
 
   // Ensure there's enough space left in the current section.

-------------

PR: https://git.openjdk.org/jdk/pull/9672