RFR: 8302369: Reduce the stack size of the C1 compiler [v2]

[Dean Long]

On Thu, 16 Feb 2023 11:17:05 GMT, SUN Guoyun <duke at openjdk.org> wrote:

>> The current fact is that C1 uses more stack space than the C2 compiler, taking method `java.lang.Object::<init>`as an example on the x86_64 platform , the stack size used is 48 bytes for C1 compiler, while only 16 bytes is used for C2 compiler.
>> 
>> ========== C1-compiled nmethod =====
>> 0x00007f93311cc747: push %rbp
>> 0x00007f93311cc748: sub $0x30,%rsp // stack sizes is 48 bytes
>> 
>> 
>> ========== C2-compiled nmethod =======
>>     pushq rbp # Save rbp
>>     subq rsp, #16 # Create frame //stack sizes is 16 bytes
>> 
>> After this patch, the C1 compiler will use less stack space. also taking method `java.lang.Object::<init>`as an example on the x86_64 platform , the stack size used is 16 bytes on L1 and 32 bytes on L3.
>> 
>> ========== C1-compiled nmethod =====
>> Compiled method (c1)     264   24       1       java.lang.Object::<init> (1 bytes)
>> 0x00007f80491ce647:   push   %rbp
>> 0x00007f80491ce648:   sub    $0x10,%rsp   //stack sizes is 16 bytes
>> 
>> ========== C1-compiled nmethod =====
>> Compiled method (c1)     283   24       3       java.lang.Object::<init> (1 bytes)
>> 0x00007f93711d01c7:   push   %rbp
>> 0x00007f93711d01c8:   sub    $0x20,%rsp  // stack sizes is 32 bytes
>
> SUN Guoyun has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8302369: Reduce the stack size of the C1 compiler

src/hotspot/share/c1/c1_CodeStubs.hpp line 568:

> 566:     f->update_reserved_argument_area_size(2 * BytesPerWord);
> 567: #endif
> 568:   }

How about moving the CPU-specific value to CPU-specific code?  Maybe `c1_Defs_<cpu>.hpp`?

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PR: https://git.openjdk.org/jdk/pull/12548