AArch64: Consider snippets size when aborting compilation of huge met…

…hods

A workaround for huge methods was introduced in #5819 because the range of
AArch64 conditional branch is +/- 1MB.
This commit enhances the workaround by taking into account the size of
snippets which was disregarded in #5819.

Signed-off-by: Akira Saitoh <saiaki@jp.ibm.com>

compiler/aarch64/codegen/OMRCodeGenerator.cpp

@@ -256,6 +256,13 @@ OMR::ARM64::CodeGenerator::doBinaryEncoding()
 
    self()->setEstimatedCodeLength(data.estimate);
 
+   if (!constantIsSignedImm21(data.estimate))
+      {
+      // Workaround for huge code
+      // Range of conditional branch instruction is +/- 1MB
+      self()->comp()->failCompilation<TR::AssertionFailure>("Generated code is too large");
+      }
+
    data.cursorInstruction = self()->getFirstInstruction();
    uint8_t *coldCode = NULL;
    uint8_t *temp = self()->allocateCodeMemory(self()->getEstimatedCodeLength(), 0, &coldCode);
@@ -297,13 +304,6 @@ OMR::ARM64::CodeGenerator::doBinaryEncoding()
       ++oiIterator;
       }
 
-   if (!constantIsSignedImm21((intptr_t)self()->getBinaryBufferCursor() - (intptr_t)self()->getBinaryBufferStart()))
-      {
-      // Workaround for huge code
-      // Range of conditional branch instruction is +/- 1MB
-      self()->comp()->failCompilation<TR::AssertionFailure>("Generated code is too large");
-      }
-
    self()->getLinkage()->performPostBinaryEncoding();
    }