The Tor Browser / file revision

 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-

  *

  * This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 // Implement shared vtbl methods.

 #include "xptcprivate.h"

 #include "xptiprivate.h"

 // The Linux/x86-64 ABI passes the first 6 integer parameters and the

 // first 8 floating point parameters in registers (rdi, rsi, rdx, rcx,

 // r8, r9 and xmm0-xmm7), no stack space is allocated for these by the

 // caller.  The rest of the parameters are passed in the callers stack

 // area.

 const uint32_t PARAM_BUFFER_COUNT   = 16;

 const uint32_t GPR_COUNT            = 6;

 const uint32_t FPR_COUNT            = 8;

 // PrepareAndDispatch() is called by SharedStub() and calls the actual method.

 //

 // - 'args[]' contains the arguments passed on stack

 // - 'gpregs[]' contains the arguments passed in integer registers

 // - 'fpregs[]' contains the arguments passed in floating point registers

 // 

 // The parameters are mapped into an array of type 'nsXPTCMiniVariant'

 // and then the method gets called.

 extern "C" nsresult ATTRIBUTE_USED

 PrepareAndDispatch(nsXPTCStubBase * self, uint32_t methodIndex,

                    uint64_t * args, uint64_t * gpregs, double *fpregs)

 {

     nsXPTCMiniVariant paramBuffer[PARAM_BUFFER_COUNT];

     nsXPTCMiniVariant* dispatchParams = nullptr;

     const nsXPTMethodInfo* info;

     uint32_t paramCount;

     uint32_t i;

     nsresult result = NS_ERROR_FAILURE;

     NS_ASSERTION(self,"no self");

     self->mEntry->GetMethodInfo(uint16_t(methodIndex), &info);

     NS_ASSERTION(info,"no method info");

     if (!info)

         return NS_ERROR_UNEXPECTED;

     paramCount = info->GetParamCount();

     // setup variant array pointer

     if (paramCount > PARAM_BUFFER_COUNT)

         dispatchParams = new nsXPTCMiniVariant[paramCount];

     else

         dispatchParams = paramBuffer;

     NS_ASSERTION(dispatchParams,"no place for params");

     if (!dispatchParams)

         return NS_ERROR_OUT_OF_MEMORY;

     uint64_t* ap = args;

     uint32_t nr_gpr = 1;    // skip one GPR register for 'that'

     uint32_t nr_fpr = 0;

     uint64_t value;

     for (i = 0; i < paramCount; i++) {

         const nsXPTParamInfo& param = info->GetParam(i);

         const nsXPTType& type = param.GetType();

         nsXPTCMiniVariant* dp = &dispatchParams[i];

         if (!param.IsOut() && type == nsXPTType::T_DOUBLE) {

             if (nr_fpr < FPR_COUNT)

                 dp->val.d = fpregs[nr_fpr++];

             else

                 dp->val.d = *(double*) ap++;

             continue;

         }

         else if (!param.IsOut() && type == nsXPTType::T_FLOAT) {

             if (nr_fpr < FPR_COUNT)

                 // The value in %xmm register is already prepared to

                 // be retrieved as a float. Therefore, we pass the

                 // value verbatim, as a double without conversion.

                 dp->val.d = *(double*) ap++;

             else

                 dp->val.f = *(float*) ap++;

             continue;

         }

         else {

             if (nr_gpr < GPR_COUNT)

                 value = gpregs[nr_gpr++];

             else

                 value = *ap++;

         }

         if (param.IsOut() || !type.IsArithmetic()) {

             dp->val.p = (void*) value;

             continue;

         }

         switch (type) {

         case nsXPTType::T_I8:      dp->val.i8  = (int8_t)   value; break;

         case nsXPTType::T_I16:     dp->val.i16 = (int16_t)  value; break;

         case nsXPTType::T_I32:     dp->val.i32 = (int32_t)  value; break;

         case nsXPTType::T_I64:     dp->val.i64 = (int64_t)  value; break;

         case nsXPTType::T_U8:      dp->val.u8  = (uint8_t)  value; break;

         case nsXPTType::T_U16:     dp->val.u16 = (uint16_t) value; break;

         case nsXPTType::T_U32:     dp->val.u32 = (uint32_t) value; break;

         case nsXPTType::T_U64:     dp->val.u64 = (uint64_t) value; break;

         case nsXPTType::T_BOOL:    dp->val.b   = (bool)   value; break;

         case nsXPTType::T_CHAR:    dp->val.c   = (char)     value; break;

         case nsXPTType::T_WCHAR:   dp->val.wc  = (wchar_t)  value; break;

         default:

             NS_ERROR("bad type");

             break;

         }

     }

     result = self->mOuter->CallMethod((uint16_t) methodIndex, info, dispatchParams);

     if (dispatchParams != paramBuffer)

         delete [] dispatchParams;

     return result;

 }

 // Linux/x86-64 uses gcc >= 3.1

 #define STUB_ENTRY(n) \

 asm(".section	\".text\"\n\t" \

     ".align	2\n\t" \

     ".if	" #n " < 10\n\t" \

     ".globl	_ZN14nsXPTCStubBase5Stub" #n "Ev\n\t" \

     ".hidden	_ZN14nsXPTCStubBase5Stub" #n "Ev\n\t" \

     ".type	_ZN14nsXPTCStubBase5Stub" #n "Ev,@function\n" \

     "_ZN14nsXPTCStubBase5Stub" #n "Ev:\n\t" \

     ".elseif	" #n " < 100\n\t" \

     ".globl	_ZN14nsXPTCStubBase6Stub" #n "Ev\n\t" \

     ".hidden	_ZN14nsXPTCStubBase6Stub" #n "Ev\n\t" \

     ".type	_ZN14nsXPTCStubBase6Stub" #n "Ev,@function\n" \

     "_ZN14nsXPTCStubBase6Stub" #n "Ev:\n\t" \

     ".elseif    " #n " < 1000\n\t" \

     ".globl     _ZN14nsXPTCStubBase7Stub" #n "Ev\n\t" \

     ".hidden    _ZN14nsXPTCStubBase7Stub" #n "Ev\n\t" \

     ".type      _ZN14nsXPTCStubBase7Stub" #n "Ev,@function\n" \

     "_ZN14nsXPTCStubBase7Stub" #n "Ev:\n\t" \

     ".else\n\t" \

     ".err	\"stub number " #n " >= 1000 not yet supported\"\n\t" \

     ".endif\n\t" \

     "movl	$" #n ", %eax\n\t" \

     "jmp	SharedStub\n\t" \

     ".if	" #n " < 10\n\t" \

     ".size	_ZN14nsXPTCStubBase5Stub" #n "Ev,.-_ZN14nsXPTCStubBase5Stub" #n "Ev\n\t" \

     ".elseif	" #n " < 100\n\t" \

     ".size	_ZN14nsXPTCStubBase6Stub" #n "Ev,.-_ZN14nsXPTCStubBase6Stub" #n "Ev\n\t" \

     ".else\n\t" \

     ".size	_ZN14nsXPTCStubBase7Stub" #n "Ev,.-_ZN14nsXPTCStubBase7Stub" #n "Ev\n\t" \

     ".endif");

 // static nsresult SharedStub(uint32_t methodIndex)

 asm(".section   \".text\"\n\t"

     ".align     2\n\t"

     ".type      SharedStub,@function\n\t"

     "SharedStub:\n\t"

     // make room for gpregs (48), fpregs (64)

     "pushq      %rbp\n\t"

     "movq       %rsp,%rbp\n\t"

     "subq       $112,%rsp\n\t"

     // save GP registers

     "movq       %rdi,-112(%rbp)\n\t"

     "movq       %rsi,-104(%rbp)\n\t"

     "movq       %rdx, -96(%rbp)\n\t"

     "movq       %rcx, -88(%rbp)\n\t"

     "movq       %r8 , -80(%rbp)\n\t"

     "movq       %r9 , -72(%rbp)\n\t"

     "leaq       -112(%rbp),%rcx\n\t"

     // save FP registers

     "movsd      %xmm0,-64(%rbp)\n\t"

     "movsd      %xmm1,-56(%rbp)\n\t"

     "movsd      %xmm2,-48(%rbp)\n\t"

     "movsd      %xmm3,-40(%rbp)\n\t"

     "movsd      %xmm4,-32(%rbp)\n\t"

     "movsd      %xmm5,-24(%rbp)\n\t"

     "movsd      %xmm6,-16(%rbp)\n\t"

     "movsd      %xmm7, -8(%rbp)\n\t"

     "leaq       -64(%rbp),%r8\n\t"

     // rdi has the 'self' pointer already

     "movl       %eax,%esi\n\t"

     "leaq       16(%rbp),%rdx\n\t"

     "call       PrepareAndDispatch@plt\n\t"

     "leave\n\t"

     "ret\n\t"

     ".size      SharedStub,.-SharedStub");

 #define SENTINEL_ENTRY(n) \

 nsresult nsXPTCStubBase::Sentinel##n() \

 { \

     NS_ERROR("nsXPTCStubBase::Sentinel called"); \

     return NS_ERROR_NOT_IMPLEMENTED; \

 }

 #include "xptcstubsdef.inc"