svn commit: r364809 - head/share/mk

[Alex Richardson]

Author: arichardson
Date: Wed Aug 26 10:21:38 2020
New Revision: 364809
URL: https://svnweb.freebsd.org/changeset/base/364809

Log:
  Avoid recomputing COMPILER_/LINKER_ variables when set explicitly
  
  I noticed that when we build libraries for a different ABI (in CheriBSD) we
  were calling ${XCC}/${LD} --version for every directory. It turns out that
  this was caused by bsd.compat.mk explicitly setting (X_)COMPILER variables
  for that build stage and this stops the _can_export logic from working.
  To fix this, we change the check to only set _can_export=no if the variable
  is set and it is set to a different value than the cached value.
  This noticeably speeds up the tree walk while building compat libraries.
  During an upstream amd64 buildworld this also removes 8 --version calls.
  
  Obtained from:	CheriBSD
  Reviewed By:	brooks, emaste
  Differential Revision: https://reviews.freebsd.org/D25986

Modified:
  head/share/mk/bsd.compiler.mk
  head/share/mk/bsd.linker.mk

Modified: head/share/mk/bsd.compiler.mk
==============================================================================
--- head/share/mk/bsd.compiler.mk	Wed Aug 26 09:19:49 2020	(r364808)
+++ head/share/mk/bsd.compiler.mk	Wed Aug 26 10:21:38 2020	(r364809)
@@ -146,10 +146,13 @@ _exported_vars=	${X_}COMPILER_TYPE ${X_}COMPILER_VERSI
 		${X_}COMPILER_FREEBSD_VERSION ${X_}COMPILER_RESOURCE_DIR
 ${X_}_cc_hash=	${${cc}}${MACHINE}${PATH}
 ${X_}_cc_hash:=	${${X_}_cc_hash:hash}
-# Only import if none of the vars are set somehow else.
+# Only import if none of the vars are set differently somehow else.
 _can_export=	yes
 .for var in ${_exported_vars}
-.if defined(${var})
+.if defined(${var}) && (!defined(${var}__${${X_}_cc_hash}) || ${${var}__${${X_}_cc_hash}} != ${${var}})
+.if defined(${var}__${${X_}_ld_hash})
+.info "Cannot import ${X_}COMPILER variables since cached ${var} is different: ${${var}__${${X_}_cc_hash}} != ${${var}}"
+.endif
 _can_export=	no
 .endif
 .endfor

Modified: head/share/mk/bsd.linker.mk
==============================================================================
--- head/share/mk/bsd.linker.mk	Wed Aug 26 09:19:49 2020	(r364808)
+++ head/share/mk/bsd.linker.mk	Wed Aug 26 10:21:38 2020	(r364809)
@@ -41,10 +41,13 @@ _exported_vars=	${X_}LINKER_TYPE ${X_}LINKER_VERSION $
 		${X_}LINKER_FREEBSD_VERSION
 ${X_}_ld_hash=	${${ld}}${MACHINE}${PATH}
 ${X_}_ld_hash:=	${${X_}_ld_hash:hash}
-# Only import if none of the vars are set somehow else.
+# Only import if none of the vars are set differently somehow else.
 _can_export=	yes
 .for var in ${_exported_vars}
-.if defined(${var})
+.if defined(${var}) && (!defined(${var}__${${X_}_ld_hash}) || ${${var}__${${X_}_ld_hash}} != ${${var}})
+.if defined(${var}__${${X_}_ld_hash})
+.info "Cannot import ${X_}LINKER variables since cached ${var} is different: ${${var}__${${X_}_ld_hash}} != ${${var}}"
+.endif
 _can_export=	no
 .endif
 .endfor