diff options
author | amonakov <amonakov@138bc75d-0d04-0410-961f-82ee72b054a4> | 2015-05-11 13:20:57 +0000 |
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committer | H.J. Lu <hjl.tools@gmail.com> | 2015-08-18 04:49:33 -0700 |
commit | 045ed2eca0004a9e622ce426eb5c487507304441 (patch) | |
tree | 30d8f2af05971300437d309c3ade84e610a42c68 | |
parent | b66dfbac2f909cfbc328adbcf58164643fd4132b (diff) | |
download | gcc-045ed2eca0004a9e622ce426eb5c487507304441.tar.gz |
* calls.c (prepare_call_address): Transform PLT call to GOT lookup and
indirect call by forcing address into a pseudo with -fno-plt.
* common.opt (flag_plt): New option.
* doc/invoke.texi (Code Generation Options): Add -fno-plt.
([-fno-plt]): Document.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@223003 138bc75d-0d04-0410-961f-82ee72b054a4
-rw-r--r-- | gcc/calls.c | 6 | ||||
-rw-r--r-- | gcc/common.opt | 4 | ||||
-rw-r--r-- | gcc/doc/invoke.texi | 12 |
3 files changed, 21 insertions, 1 deletions
diff --git a/gcc/calls.c b/gcc/calls.c index 0987dd0a911..38a564e3907 100644 --- a/gcc/calls.c +++ b/gcc/calls.c @@ -225,6 +225,12 @@ prepare_call_address (tree fndecl_or_type, rtx funexp, rtx static_chain_value, && targetm.small_register_classes_for_mode_p (FUNCTION_MODE)) ? force_not_mem (memory_address (FUNCTION_MODE, funexp)) : memory_address (FUNCTION_MODE, funexp)); + else if (flag_pic && !flag_plt && fndecl_or_type + && TREE_CODE (fndecl_or_type) == FUNCTION_DECL + && !targetm.binds_local_p (fndecl_or_type)) + { + funexp = force_reg (Pmode, funexp); + } else if (! sibcallp) { #ifndef NO_FUNCTION_CSE diff --git a/gcc/common.opt b/gcc/common.opt index 1218a71fe47..593d39bf465 100644 --- a/gcc/common.opt +++ b/gcc/common.opt @@ -1779,6 +1779,10 @@ fpie Common Report Var(flag_pie,1) Negative(fPIC) Generate position-independent code for executables if possible (small mode) +fplt +Common Report Var(flag_plt) Init(1) Optimization +Use PLT for PIC calls (-fno-plt: load the address from GOT at call site) + fplugin= Common Joined RejectNegative Var(common_deferred_options) Defer Specify a plugin to load diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index f84a1994aa1..d5be7b223a6 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -1123,7 +1123,7 @@ See S/390 and zSeries Options. -finstrument-functions-exclude-function-list=@var{sym},@var{sym},@dots{} @gol -finstrument-functions-exclude-file-list=@var{file},@var{file},@dots{} @gol -fno-common -fno-ident @gol --fpcc-struct-return -fpic -fPIC -fpie -fPIE @gol +-fpcc-struct-return -fpic -fPIC -fpie -fPIE -fno-plt @gol -fno-jump-tables @gol -frecord-gcc-switches @gol -freg-struct-return -fshort-enums @gol @@ -23628,6 +23628,16 @@ used during linking. @code{__pie__} and @code{__PIE__}. The macros have the value 1 for @option{-fpie} and 2 for @option{-fPIE}. +@item -fno-plt +@opindex fno-plt +Do not use PLT for external function calls in position-independent code. +Instead, load callee address at call site from GOT and branch to it. +This leads to more efficient code by eliminating PLT stubs and exposing +GOT load to optimizations. On architectures such as 32-bit x86 where +PLT stubs expect GOT pointer in a specific register, this gives more +register allocation freedom to the compiler. Lazy binding requires PLT: +with @option{-fno-plt} all external symbols are resolved at load time. + @item -fno-jump-tables @opindex fno-jump-tables Do not use jump tables for switch statements even where it would be |