[binutils-gdb/binutils-2_31-branch] gas: Pass max_bytes to TC_FRAG_INIT

[H.J.Lu]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=292144de4f26e2c6a1fa9d84da2c7758872d4725

commit 292144de4f26e2c6a1fa9d84da2c7758872d4725
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Sun Feb 10 04:34:10 2019 -0800

    gas: Pass max_bytes to TC_FRAG_INIT
    
    ommit 3ae729d5a4f63740ed9a778960b17c2912b0bbdd
    Author: H.J. Lu <hjl.tools@gmail.com>
    Date:   Wed Mar 7 04:18:45 2018 -0800
    
        x86: Rewrite NOP generation for fill and alignment
    
    increased MAX_MEM_FOR_RS_ALIGN_CODE to 4095 which resulted in increase
    of assembler time and memory usage by 5 times for inputs with many
    .p2align directives, which is typical for LTO output.  This patch passes
    max_bytes to TC_FRAG_INIT so that MAX_MEM_FOR_RS_ALIGN_CODE can be set
    as needed and tracked by backend it so that HANDLE_ALIGN can check the
    maximum alignment for each rs_align_code frag.  Wall time to assemble
    the same cc1plus.s:
    
    before:
    
    423.78user 0.89system 7:05.71elapsed 99%CPU
    
    after:
    
    102.35user 0.27system 1:42.89elapsed 99%CPU
    
    	PR gas/24165
    	* config/tc-i386.h (MAX_MEM_FOR_RS_ALIGN_CODE): Set to
    	(alignment ? ((1 << alignment) - 1) : 1)
    	(i386_tc_frag_data): Add max_bytes.
    	(TC_FRAG_INIT): Track max_chars in max_bytes.
    	(HANDLE_ALIGN): Replace MAX_MEM_FOR_RS_ALIGN_CODE with
    	fragP->tc_frag_data.max_bytes.
    
    (cherry picked from commit db22231044df03bbcb987496f3f29f0462b2e9ee)

Diff:
---
 gas/ChangeLog        | 10 ++++++++++
 gas/config/tc-i386.h |  8 ++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 0e00437..97d370d 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,13 @@
+2019-02-10  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR gas/24165
+	* config/tc-i386.h (MAX_MEM_FOR_RS_ALIGN_CODE): Set to
+	(alignment ? ((1 << alignment) - 1) : 1)
+	(i386_tc_frag_data): Add max_bytes.
+	(TC_FRAG_INIT): Track max_chars in max_bytes.
+	(HANDLE_ALIGN): Replace MAX_MEM_FOR_RS_ALIGN_CODE with
+	fragP->tc_frag_data.max_bytes.
+
 2019-02-07  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* config/tc-visium.c (md_assemble) <mode_cad>: Align instruction on
diff --git a/gas/config/tc-i386.h b/gas/config/tc-i386.h
index 830ac57..46a0381 100644
--- a/gas/config/tc-i386.h
+++ b/gas/config/tc-i386.h
@@ -206,7 +206,7 @@ if ((n)									\
     goto around;							\
   }
 
-#define MAX_MEM_FOR_RS_ALIGN_CODE 4095
+#define MAX_MEM_FOR_RS_ALIGN_CODE  (alignment ? ((1 << alignment) - 1) : 1)
 
 void i386_print_statistics (FILE *);
 #define tc_print_statistics i386_print_statistics
@@ -251,6 +251,7 @@ struct i386_tc_frag_data
   enum processor_type isa;
   i386_cpu_flags isa_flags;
   enum processor_type tune;
+  unsigned int max_bytes;
 };
 
 /* We need to emit the right NOP pattern in .align frags.  This is
@@ -258,12 +259,14 @@ struct i386_tc_frag_data
    the isa/tune settings at the time the .align was assembled.  */
 #define TC_FRAG_TYPE struct i386_tc_frag_data
 
+/* NB: max_chars is a local variable in frag_var_init.  */
 #define TC_FRAG_INIT(FRAGP)					\
  do								\
    {								\
      (FRAGP)->tc_frag_data.isa = cpu_arch_isa;			\
      (FRAGP)->tc_frag_data.isa_flags = cpu_arch_isa_flags;	\
      (FRAGP)->tc_frag_data.tune = cpu_arch_tune;		\
+     (FRAGP)->tc_frag_data.max_bytes = max_chars;		\
    }								\
  while (0)
 
@@ -280,7 +283,8 @@ if (fragP->fr_type == rs_align_code) 					\
     offsetT __count = (fragP->fr_next->fr_address			\
 		       - fragP->fr_address				\
 		       - fragP->fr_fix);				\
-    if (__count > 0 && __count <= MAX_MEM_FOR_RS_ALIGN_CODE)		\
+    if (__count > 0							\
+	&& (unsigned int) __count <= fragP->tc_frag_data.max_bytes)	\
       md_generate_nops (fragP, fragP->fr_literal + fragP->fr_fix,	\
 			__count, 0);					\
   }