gcc/gcc8-rh1668903-3.patch

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commit 77e6311332590004c5aec82ceeb45e4d4d93f690
Author: redi <redi@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Thu Apr 11 08:52:22 2019 +0000
Clarify documentation for -flive-patching
* doc/invoke.texi (Optimize Options): Clarify -flive-patching docs.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@270276 138bc75d-0d04-0410-961f-82ee72b054a4
--- gcc/doc/invoke.texi
+++ gcc/doc/invoke.texi
@@ -9367,24 +9367,24 @@ This flag is enabled by default at @option{-O2} and @option{-Os}.
@item -flive-patching=@var{level}
@opindex flive-patching
-Control GCC's optimizations to provide a safe compilation for live-patching.
+Control GCC's optimizations to produce output suitable for live-patching.
If the compiler's optimization uses a function's body or information extracted
from its body to optimize/change another function, the latter is called an
impacted function of the former. If a function is patched, its impacted
functions should be patched too.
-The impacted functions are decided by the compiler's interprocedural
-optimizations. For example, inlining a function into its caller, cloning
-a function and changing its caller to call this new clone, or extracting
-a function's pureness/constness information to optimize its direct or
-indirect callers, etc.
+The impacted functions are determined by the compiler's interprocedural
+optimizations. For example, a caller is impacted when inlining a function
+into its caller,
+cloning a function and changing its caller to call this new clone,
+or extracting a function's pureness/constness information to optimize
+its direct or indirect callers, etc.
Usually, the more IPA optimizations enabled, the larger the number of
impacted functions for each function. In order to control the number of
-impacted functions and computed the list of impacted function easily,
-we provide control to partially enable IPA optimizations on two different
-levels.
+impacted functions and more easily compute the list of impacted function,
+IPA optimizations can be partially enabled at two different levels.
The @var{level} argument should be one of the following:
@@ -9395,7 +9395,7 @@ The @var{level} argument should be one of the following:
Only enable inlining and cloning optimizations, which includes inlining,
cloning, interprocedural scalar replacement of aggregates and partial inlining.
As a result, when patching a function, all its callers and its clones'
-callers need to be patched as well.
+callers are impacted, therefore need to be patched as well.
@option{-flive-patching=inline-clone} disables the following optimization flags:
@gccoptlist{-fwhole-program -fipa-pta -fipa-reference -fipa-ra @gol
@@ -9406,22 +9406,23 @@ callers need to be patched as well.
@item inline-only-static
Only enable inlining of static functions.
-As a result, when patching a static function, all its callers need to be
-patches as well.
+As a result, when patching a static function, all its callers are impacted
+and so need to be patched as well.
-In addition to all the flags that -flive-patching=inline-clone disables,
+In addition to all the flags that @option{-flive-patching=inline-clone}
+disables,
@option{-flive-patching=inline-only-static} disables the following additional
optimization flags:
@gccoptlist{-fipa-cp-clone -fipa-sra -fpartial-inlining -fipa-cp}
@end table
-When -flive-patching specified without any value, the default value
-is "inline-clone".
+When @option{-flive-patching} is specified without any value, the default value
+is @var{inline-clone}.
This flag is disabled by default.
-Note that -flive-patching is not supported with link-time optimizer.
+Note that @option{-flive-patching} is not supported with link-time optimization
(@option{-flto}).
@item -fisolate-erroneous-paths-dereference