Fine. Here is a adjusted version which keeps old abi behavior for chain-registers.
2012-11-28 Kai Tietz PR target/55171 * i386.c (get_scratch_register_on_entry): Handle thiscall-convention. (split_stack_prologue_scratch_regno): Likewise. (ix86_static_chain): Likewise. (x86_output_mi_thunk): Likewise. Test on i686-w64-mingw32. Ok for apply? Regards, Kai Index: i386.c =================================================================== --- i386.c (Revision 193781) +++ i386.c (Arbeitskopie) @@ -9655,6 +9655,8 @@ tree decl = current_function_decl, fntype = TREE_TYPE (decl); bool fastcall_p = lookup_attribute ("fastcall", TYPE_ATTRIBUTES (fntype)) != NULL_TREE; + bool thiscall_p + = lookup_attribute ("thiscall", TYPE_ATTRIBUTES (fntype)) != NULL_TREE; bool static_chain_p = DECL_STATIC_CHAIN (decl); int regparm = ix86_function_regparm (fntype, decl); int drap_regno @@ -9665,10 +9667,15 @@ if ((regparm < 1 || (fastcall_p && !static_chain_p)) && drap_regno != AX_REG) regno = AX_REG; - else if (regparm < 2 && drap_regno != DX_REG) + /* 'thiscall' sets regparm to 1, uses ecx for arguments and edx + for the static chain register. */ + else if (thiscall_p && !static_chain_p && drap_regno != AX_REG) + regno = AX_REG; + else if (regparm < 2 && !thiscall_p && drap_regno != DX_REG) regno = DX_REG; /* ecx is the static chain register. */ - else if (regparm < 3 && !fastcall_p && !static_chain_p + else if (regparm < 3 && !fastcall_p && !thiscall_p + && !static_chain_p && drap_regno != CX_REG) regno = CX_REG; else if (ix86_save_reg (BX_REG, true)) @@ -11180,12 +11187,15 @@ return R11_REG; else { - bool is_fastcall; + bool is_fastcall, is_thiscall; int regparm; is_fastcall = (lookup_attribute ("fastcall", TYPE_ATTRIBUTES (TREE_TYPE (cfun->decl))) != NULL); + is_thiscall = (lookup_attribute ("thiscall", + TYPE_ATTRIBUTES (TREE_TYPE (cfun->decl))) + != NULL); regparm = ix86_function_regparm (TREE_TYPE (cfun->decl), cfun->decl); if (is_fastcall) @@ -11198,6 +11208,12 @@ } return AX_REG; } + else if (is_thiscall) + { + if (!DECL_STATIC_CHAIN (cfun->decl)) + return DX_REG; + return AX_REG; + } else if (regparm < 3) { if (!DECL_STATIC_CHAIN (cfun->decl)) @@ -25134,7 +25150,7 @@ fntype = TREE_TYPE (fndecl); ccvt = ix86_get_callcvt (fntype); - if ((ccvt & (IX86_CALLCVT_FASTCALL | IX86_CALLCVT_THISCALL)) != 0) + if ((ccvt & IX86_CALLCVT_FASTCALL) != 0) { /* Fastcall functions use ecx/edx for arguments, which leaves us with EAX for the static chain. @@ -25142,6 +25158,13 @@ leaves us with EAX for the static chain. */ regno = AX_REG; } + else if ((ccvt & IX86_CALLCVT_THISCALL) != 0) + { + /* Thiscall functions use ecx for arguments, which leaves + us with EAX and EDX for the static chain. + We are using for abi-compatibility EAX. */ + regno = AX_REG; + } else if (ix86_function_regparm (fntype, fndecl) == 3) { /* For regparm 3, we have no free call-clobbered registers in @@ -34799,8 +34822,10 @@ else { unsigned int ccvt = ix86_get_callcvt (TREE_TYPE (function)); - if ((ccvt & (IX86_CALLCVT_FASTCALL | IX86_CALLCVT_THISCALL)) != 0) + if ((ccvt & IX86_CALLCVT_FASTCALL) != 0) tmp_regno = AX_REG; + else if ((ccvt & IX86_CALLCVT_THISCALL) != 0) + tmp_regno = DX_REG; else tmp_regno = CX_REG; }