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ppc platforms: fix missing TOC restoration room

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PPC platforms that use a TOC can never use a tail call to call a different
routine that potentially accesses globals, as it may use a different TOC and
then the linker must be able to insert an instruction after the branch to
restore the original TOC register value on "return". Even if FPC code itself
does not use the TOC register, it's still required since
  1) the linker does not know this, and
  2) the FPC code might still be called from other code that does use it
This commit is contained in:
Jonas Maebe 2022-02-05 21:34:00 +01:00
parent 83c18df69a
commit 68b5ca633c
2 changed files with 16 additions and 3 deletions
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9
compiler/ncgvmt.pas
View File

@ -1229,11 +1229,14 @@ implementation
{$if defined(cpuhighleveltarget)}
usehighlevelwrapper:=true;
{$else defined(cpuhighleveltarget)}
{$if defined(powerpc64)}
if cs_create_pic in current_settings.moduleswitches then
{ on PPC systems that use a TOC the linker needs to be able to insert
an instruction to restore the TOC register after every branch
between code fragments that use a different TOC (which has to be
executed when that "branch" returns). So we can't use tail call
branches to routines potentially using a different TOC there }
if target_info.system in systems_ppc_toc then
usehighlevelwrapper:=true
else
{$endif defined(powerpc64)}
usehighlevelwrapper:=false;
{$endif defined(cpuhighleveltarget)}
for i:=0 to _class.ImplementedInterfaces.count-1 do

10
compiler/systems.pas
View File

@ -448,6 +448,16 @@ interface
on the caller side rather than on the callee side }
systems_caller_copy_addr_value_para = [system_aarch64_ios,system_aarch64_darwin,system_aarch64_linux,system_aarch64_win64,system_aarch64_freebsd];
{ all PPC systems that use a TOC register to address globals }
{ TODO: not used by Darwin, but don't know about others (JM) }
systems_ppc_toc = [
system_powerpc_linux,
system_powerpc64_linux,
system_powerpc_aix,
system_powerpc64_aix,
system_powerpc_macosclassic
];
{ pointer checking (requires special code in FPC_CHECKPOINTER,
and can never work for libc-based targets or any other program
linking to an external library)