407 lines
14 KiB
Diff
407 lines
14 KiB
Diff
commit 126dab7c9d84294f256b1f7bf91c24a9e7103249
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Author: qinzhao <qinzhao@138bc75d-0d04-0410-961f-82ee72b054a4>
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Date: Thu Nov 29 16:06:03 2018 +0000
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Add a new option -flive-patching={inline-only-static|inline-clone}
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to support live patching in GCC.
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2018-11-29 qing zhao <qing.zhao@oracle.com>
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gcc/ChangeLog:
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* cif-code.def (EXTERN_LIVE_ONLY_STATIC): New CIF code.
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* common.opt: Add -flive-patching flag.
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* doc/invoke.texi: Document -flive-patching.
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* flag-types.h (enum live_patching_level): New enum.
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* ipa-inline.c (can_inline_edge_p): Disable external functions from
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inlining when flag_live_patching is LIVE_PATCHING_INLINE_ONLY_STATIC.
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* opts.c (control_options_for_live_patching): New function.
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(finish_options): Make flag_live_patching incompatible with flag_lto.
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Control IPA optimizations based on different levels of
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flag_live_patching.
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gcc/testsuite/ChangeLog:
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* gcc.dg/live-patching-1.c: New test.
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* gcc.dg/live-patching-2.c: New test.
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* gcc.dg/live-patching-3.c: New test.
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* gcc.dg/tree-ssa/writeonly-3.c: New test.
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* gcc.target/i386/ipa-stack-alignment-2.c: New test.
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git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@266627 138bc75d-0d04-0410-961f-82ee72b054a4
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--- gcc/cif-code.def
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+++ gcc/cif-code.def
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@@ -132,6 +132,12 @@ DEFCIFCODE(USES_COMDAT_LOCAL, CIF_FINAL_ERROR,
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DEFCIFCODE(ATTRIBUTE_MISMATCH, CIF_FINAL_ERROR,
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N_("function attribute mismatch"))
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+/* We can't inline because the user requests only static functions
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+ but the function has external linkage for live patching purpose. */
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+DEFCIFCODE(EXTERN_LIVE_ONLY_STATIC, CIF_FINAL_ERROR,
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+ N_("function has external linkage when the user requests only"
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+ " inlining static for live patching"))
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+
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/* We proved that the call is unreachable. */
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DEFCIFCODE(UNREACHABLE, CIF_FINAL_ERROR,
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N_("unreachable"))
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--- gcc/common.opt
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+++ gcc/common.opt
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@@ -2181,6 +2181,24 @@ starts and when the destructor finishes.
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flifetime-dse=
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Common Joined RejectNegative UInteger Var(flag_lifetime_dse) Optimization IntegerRange(0, 2)
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+flive-patching
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+Common RejectNegative Alias(flive-patching=,inline-clone) Optimization
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+
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+flive-patching=
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+Common Report Joined RejectNegative Enum(live_patching_level) Var(flag_live_patching) Init(LIVE_PATCHING_NONE) Optimization
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+-flive-patching=[inline-only-static|inline-clone] Control IPA
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+optimizations to provide a safe compilation for live-patching. At the same
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+time, provides multiple-level control on the enabled IPA optimizations.
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+
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+Enum
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+Name(live_patching_level) Type(enum live_patching_level) UnknownError(unknown Live-Patching Level %qs)
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+
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+EnumValue
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+Enum(live_patching_level) String(inline-only-static) Value(LIVE_PATCHING_INLINE_ONLY_STATIC)
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+
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+EnumValue
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+Enum(live_patching_level) String(inline-clone) Value(LIVE_PATCHING_INLINE_CLONE)
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+
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flive-range-shrinkage
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Common Report Var(flag_live_range_shrinkage) Init(0) Optimization
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Relief of register pressure through live range shrinkage.
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--- gcc/doc/invoke.texi
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+++ gcc/doc/invoke.texi
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@@ -389,6 +389,7 @@ Objective-C and Objective-C++ Dialects}.
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-fipa-bit-cp -fipa-vrp @gol
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-fipa-pta -fipa-profile -fipa-pure-const -fipa-reference -fipa-icf @gol
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-fira-algorithm=@var{algorithm} @gol
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+-flive-patching=@var{level} @gol
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-fira-region=@var{region} -fira-hoist-pressure @gol
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-fira-loop-pressure -fno-ira-share-save-slots @gol
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-fno-ira-share-spill-slots @gol
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@@ -9291,6 +9292,65 @@ equivalences that are found only by GCC and equivalences found only by Gold.
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This flag is enabled by default at @option{-O2} and @option{-Os}.
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+@item -flive-patching=@var{level}
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+@opindex flive-patching
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+Control GCC's optimizations to provide a safe compilation for live-patching.
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+
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+If the compiler's optimization uses a function's body or information extracted
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+from its body to optimize/change another function, the latter is called an
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+impacted function of the former. If a function is patched, its impacted
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+functions should be patched too.
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+
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+The impacted functions are decided by the compiler's interprocedural
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+optimizations. For example, inlining a function into its caller, cloning
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+a function and changing its caller to call this new clone, or extracting
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+a function's pureness/constness information to optimize its direct or
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+indirect callers, etc.
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+
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+Usually, the more IPA optimizations enabled, the larger the number of
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+impacted functions for each function. In order to control the number of
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+impacted functions and computed the list of impacted function easily,
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+we provide control to partially enable IPA optimizations on two different
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+levels.
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+
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+The @var{level} argument should be one of the following:
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+
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+@table @samp
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+
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+@item inline-clone
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+
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+Only enable inlining and cloning optimizations, which includes inlining,
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+cloning, interprocedural scalar replacement of aggregates and partial inlining.
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+As a result, when patching a function, all its callers and its clones'
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+callers need to be patched as well.
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+
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+@option{-flive-patching=inline-clone} disables the following optimization flags:
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+@gccoptlist{-fwhole-program -fipa-pta -fipa-reference -fipa-ra @gol
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+-fipa-icf -fipa-icf-functions -fipa-icf-variables @gol
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+-fipa-bit-cp -fipa-vrp -fipa-pure-const -fipa-reference-addressable @gol
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+-fipa-stack-alignment}
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+
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+@item inline-only-static
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+
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+Only enable inlining of static functions.
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+As a result, when patching a static function, all its callers need to be
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+patches as well.
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+
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+In addition to all the flags that -flive-patching=inline-clone disables,
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+@option{-flive-patching=inline-only-static} disables the following additional
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+optimization flags:
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+@gccoptlist{-fipa-cp-clone -fipa-sra -fpartial-inlining -fipa-cp}
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+
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+@end table
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+
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+When -flive-patching specified without any value, the default value
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+is "inline-clone".
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+
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+This flag is disabled by default.
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+
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+Note that -flive-patching is not supported with link-time optimizer.
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+(@option{-flto}).
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+
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@item -fisolate-erroneous-paths-dereference
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@opindex fisolate-erroneous-paths-dereference
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Detect paths that trigger erroneous or undefined behavior due to
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--- gcc/flag-types.h
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+++ gcc/flag-types.h
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@@ -123,6 +123,14 @@ enum stack_reuse_level
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SR_ALL
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};
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+/* The live patching level. */
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+enum live_patching_level
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+{
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+ LIVE_PATCHING_NONE = 0,
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+ LIVE_PATCHING_INLINE_ONLY_STATIC,
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+ LIVE_PATCHING_INLINE_CLONE
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+};
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+
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/* The algorithm used for basic block reordering. */
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enum reorder_blocks_algorithm
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{
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--- gcc/ipa-inline.c
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+++ gcc/ipa-inline.c
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@@ -379,6 +379,12 @@ can_inline_edge_p (struct cgraph_edge *e, bool report,
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e->inline_failed = CIF_ATTRIBUTE_MISMATCH;
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inlinable = false;
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}
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+ else if (callee->externally_visible
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+ && flag_live_patching == LIVE_PATCHING_INLINE_ONLY_STATIC)
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+ {
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+ e->inline_failed = CIF_EXTERN_LIVE_ONLY_STATIC;
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+ inlinable = false;
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+ }
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if (!inlinable && report)
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report_inline_failed_reason (e);
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return inlinable;
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--- gcc/opts.c
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+++ gcc/opts.c
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@@ -699,6 +699,152 @@ default_options_optimization (struct gcc
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lang_mask, handlers, loc, dc);
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}
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+/* Control IPA optimizations based on different live patching LEVEL. */
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+static void
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+control_options_for_live_patching (struct gcc_options *opts,
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+ struct gcc_options *opts_set,
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+ enum live_patching_level level,
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+ location_t loc)
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+{
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+ gcc_assert (level > LIVE_PATCHING_NONE);
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+
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+ switch (level)
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+ {
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+ case LIVE_PATCHING_INLINE_ONLY_STATIC:
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+ if (opts_set->x_flag_ipa_cp_clone && opts->x_flag_ipa_cp_clone)
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+ error_at (loc,
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+ "%<-fipa-cp-clone%> is incompatible with "
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+ "%<-flive-patching=inline-only-static%>");
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+ else
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+ opts->x_flag_ipa_cp_clone = 0;
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+
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+ if (opts_set->x_flag_ipa_sra && opts->x_flag_ipa_sra)
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+ error_at (loc,
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+ "%<-fipa-sra%> is incompatible with "
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+ "%<-flive-patching=inline-only-static%>");
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+ else
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+ opts->x_flag_ipa_sra = 0;
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+
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+ if (opts_set->x_flag_partial_inlining && opts->x_flag_partial_inlining)
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+ error_at (loc,
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+ "%<-fpartial-inlining%> is incompatible with "
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+ "%<-flive-patching=inline-only-static%>");
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+ else
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+ opts->x_flag_partial_inlining = 0;
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+
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+ if (opts_set->x_flag_ipa_cp && opts->x_flag_ipa_cp)
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+ error_at (loc,
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+ "%<-fipa-cp%> is incompatible with "
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+ "%<-flive-patching=inline-only-static%>");
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+ else
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+ opts->x_flag_ipa_cp = 0;
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+
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+ /* FALLTHROUGH. */
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+ case LIVE_PATCHING_INLINE_CLONE:
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+ /* live patching should disable whole-program optimization. */
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+ if (opts_set->x_flag_whole_program && opts->x_flag_whole_program)
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+ error_at (loc,
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+ "%<-fwhole-program%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_whole_program = 0;
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+
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+ /* visibility change should be excluded by !flag_whole_program
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+ && !in_lto_p && !flag_ipa_cp_clone && !flag_ipa_sra
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+ && !flag_partial_inlining. */
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+
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+ if (opts_set->x_flag_ipa_pta && opts->x_flag_ipa_pta)
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+ error_at (loc,
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+ "%<-fipa-pta%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_ipa_pta = 0;
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+
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+ if (opts_set->x_flag_ipa_reference && opts->x_flag_ipa_reference)
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+ error_at (loc,
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+ "%<-fipa-reference%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_ipa_reference = 0;
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+
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+ if (opts_set->x_flag_ipa_ra && opts->x_flag_ipa_ra)
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+ error_at (loc,
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+ "%<-fipa-ra%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_ipa_ra = 0;
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+
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+ if (opts_set->x_flag_ipa_icf && opts->x_flag_ipa_icf)
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+ error_at (loc,
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+ "%<-fipa-icf%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_ipa_icf = 0;
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+
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+ if (opts_set->x_flag_ipa_icf_functions && opts->x_flag_ipa_icf_functions)
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+ error_at (loc,
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+ "%<-fipa-icf-functions%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_ipa_icf_functions = 0;
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+
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+ if (opts_set->x_flag_ipa_icf_variables && opts->x_flag_ipa_icf_variables)
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+ error_at (loc,
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+ "%<-fipa-icf-variables%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_ipa_icf_variables = 0;
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+
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+ if (opts_set->x_flag_ipa_bit_cp && opts->x_flag_ipa_bit_cp)
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+ error_at (loc,
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+ "%<-fipa-bit-cp%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_ipa_bit_cp = 0;
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+
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+ if (opts_set->x_flag_ipa_vrp && opts->x_flag_ipa_vrp)
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+ error_at (loc,
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+ "%<-fipa-vrp%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_ipa_vrp = 0;
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+
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+ if (opts_set->x_flag_ipa_pure_const && opts->x_flag_ipa_pure_const)
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+ error_at (loc,
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+ "%<-fipa-pure-const%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_ipa_pure_const = 0;
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+
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+ /* FIXME: disable unreachable code removal. */
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+
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+ /* discovery of functions/variables with no address taken. */
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+// GCC 8 doesn't have these options.
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+#if 0
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+ if (opts_set->x_flag_ipa_reference_addressable
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+ && opts->x_flag_ipa_reference_addressable)
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+ error_at (loc,
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+ "%<-fipa-reference-addressable%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_ipa_reference_addressable = 0;
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+
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+ /* ipa stack alignment propagation. */
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+ if (opts_set->x_flag_ipa_stack_alignment
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+ && opts->x_flag_ipa_stack_alignment)
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+ error_at (loc,
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+ "%<-fipa-stack-alignment%> is incompatible with "
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+ "%<-flive-patching=inline-only-static|inline-clone%>");
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+ else
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+ opts->x_flag_ipa_stack_alignment = 0;
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+#endif
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+
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+ break;
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+ default:
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+ gcc_unreachable ();
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+ }
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+}
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+
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/* After all options at LOC have been read into OPTS and OPTS_SET,
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finalize settings of those options and diagnose incompatible
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combinations. */
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@@ -1057,6 +1203,18 @@ finish_options (struct gcc_options *opts
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sorry ("transactional memory is not supported with "
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"%<-fsanitize=kernel-address%>");
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+ /* Currently live patching is not support for LTO. */
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+ if (opts->x_flag_live_patching && opts->x_flag_lto)
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+ sorry ("live patching is not supported with LTO");
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+
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+ /* Control IPA optimizations based on different -flive-patching level. */
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+ if (opts->x_flag_live_patching)
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+ {
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+ control_options_for_live_patching (opts, opts_set,
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+ opts->x_flag_live_patching,
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+ loc);
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+ }
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+
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/* Comes from final.c -- no real reason to change it. */
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#define MAX_CODE_ALIGN 16
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#define MAX_CODE_ALIGN_VALUE (1 << MAX_CODE_ALIGN)
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--- /dev/null
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+++ gcc/testsuite/gcc.dg/live-patching-1.c
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@@ -0,0 +1,22 @@
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+/* { dg-do compile } */
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+/* { dg-options "-O2 -flive-patching=inline-only-static -fdump-ipa-inline" } */
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+
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+extern int sum, n, m;
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+
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+int foo (int a)
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+{
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+ return a + n;
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+}
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+
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+static int bar (int b)
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+{
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+ return b * m;
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+}
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+
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+int main()
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+{
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+ sum = foo (m) + bar (n);
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+ return 0;
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+}
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+
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+/* { dg-final { scan-ipa-dump "foo/0 function has external linkage when the user requests only inlining static for live patching" "inline" } } */
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--- /dev/null
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+++ gcc/testsuite/gcc.dg/live-patching-2.c
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@@ -0,0 +1,9 @@
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+/* { dg-do compile } */
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+/* { dg-options "-O2 -flive-patching -flto" } */
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+
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+int main()
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+{
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+ return 0;
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+}
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+
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+/* { dg-message "sorry, unimplemented: live patching is not supported with LTO" "-flive-patching and -flto together" { target *-*-* } 0 } */
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--- /dev/null
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+++ gcc/testsuite/gcc.dg/live-patching-3.c
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@@ -0,0 +1,9 @@
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+/* { dg-do compile } */
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+/* { dg-options "-O1 -flive-patching -fwhole-program" } */
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+
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+int main()
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+{
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+ return 0;
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+}
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+
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+/* { dg-message "'-fwhole-program' is incompatible with '-flive-patching=inline-only-static|inline-clone’" "" {target "*-*-*"} 0 } */
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