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Diffstat (limited to 'src/Native/System.Private.TypeLoader.Native/arm/VTableResolver.asm')
| -rw-r--r-- | src/Native/System.Private.TypeLoader.Native/arm/VTableResolver.asm | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/src/Native/System.Private.TypeLoader.Native/arm/VTableResolver.asm b/src/Native/System.Private.TypeLoader.Native/arm/VTableResolver.asm new file mode 100644 index 000000000..36e244e93 --- /dev/null +++ b/src/Native/System.Private.TypeLoader.Native/arm/VTableResolver.asm @@ -0,0 +1,163 @@ +;; Licensed to the .NET Foundation under one or more agreements. +;; The .NET Foundation licenses this file to you under the MIT license. +;; See the LICENSE file in the project root for more information. + +#include "kxarm.h" + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; DATA SECTIONS ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + DATAAREA + +g_vtableResolveCallback DCD 0 ; The vtableresolve method + EXPORT g_vtableResolveCallback +g_universalTransition DCD 0 ; The address of Redhawk's UniversalTransition thunk + +#define VTableThunkSize 0x20 +;; TODO - do something similar to Redhawk's asmoffsets to compute the value at compile time +#define EETypeVTableOffset 0x14 +#define PointerSize 4 +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ConstrainedCall Support Helpers ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + + TEXTAREA +;; +;; Note: The "__jmpstub__" prefix is used to indicate to debugger +;; that it must step-through this stub when it encounters it while +;; stepping. +;; + +;; Returns the size of the pre-generated thunks +;; int VTableResolver_Init(IntPtr *__jmpstub__VTableResolverSlot0, +;; IntPtr vtableResolveCallback, +;; IntPtr universalTransition, +;; int *slotCount) +;; + LEAF_ENTRY VTableResolver_Init + ldr r12, __jmpstub__VTableSlot000 + add r12, r12, 1 ; Add thumb bit + str r12, [r0] + ldr r12, =g_vtableResolveCallback + str r1, [r12] + ldr r12, =g_universalTransition + str r2, [r12] + mov r12, 100 ; This file defines 100 slot helpers + str r12, [r3] + mov r0, VTableThunkSize ; Each thunk is VTableThunkSize in bytes + bx lr + LEAF_END VTableResolver_Init + +;; void* VTableResolver_GetCommonCallingStub() +;; - Get the address of the common calling stub + LEAF_ENTRY VTableResolver_GetCommonCallingStub + ldr r0, __jmpstub__VTableResolver_CommonCallingStub + bx lr + LEAF_END VTableResolver_GetCommonCallingStub + +;; +;; __jmpstub__VTableResolver_CommonCallingStub(?) +;; Used when we dynamically need a VTableResolver not pre-generated +;; +;; sp-4 contains a pointer to a VTableResolverStruct +;; struct VTableResolverStruct +;; { +;; int offsetFromStartOfEETypePtr; +;; IntPtr VTableThunkAddress; +;; }; +;; + LEAF_ENTRY __jmpstub__VTableResolver_CommonCallingStub + ;; Custom calling convention: + ;; red zone has pointer to the VTableResolverStruct + ;; Copy red zone value into r12 so that the PROLOG_PUSH doesn't destroy it + PROLOG_NOP ldr r12, [sp, #-4] + PROLOG_PUSH {r3} + PROLOG_PUSH {r1-r2} + ldr r2, [r0] + ;; r2 is the EEType pointer add the VTableOffset + slot_number * pointer size to get the vtable entry + ;; compare the that value to the address of the thunk being executed and if the values are equal then + ;; call to the resolver otherwise call the method + ldr r1, [r12] + ;; r1 is the offset from start of EEType to interesting slot + ldr r3, [r2,r1] + ;; r3 is now the function pointer in the vtable + ldr r2,[r12,#4] + ;; is now the address of the function pointer that serves as the entry point for this particular instantiation + ;; of __jmpstub__VTableResolver_CommonCallingStub + cmp r2,r3 + beq __jmpstub__JumpToVTableResolver + mov r12,r3 ; Move the target function pointer to r12 + EPILOG_POP {r1,r2} + EPILOG_POP {r3} + EPILOG_BRANCH_REG r12 + LEAF_END __jmpstub__VTableResolver_CommonCallingStub + +;; stub for dispatch will come in with r1 set to EETypeVTableOffset + ($slot_number * PointerSize), +;; and r1, r2 and r3 of the function we really want to call pushed on the stack + LEAF_ENTRY __jmpstub__JumpToVTableResolver + mov r3, r1 + POP {r1,r2} + str r3, [sp, #-4] ; Store slot number into red zone at appropriate spot + POP {r3} + ldr r12, =g_vtableResolveCallback + ldr r12, [r12] + str r12, [sp, #-4] ; Store vtable resolve callback into red zone + ldr r12, =g_universalTransition + ldr r12, [r12] + bx r12 + LEAF_END __jmpstub__VTableResolver_Init + + + MACRO + VTableThunkDecl $name, $slot_number + ALIGN 16 ; The alignment here forces the thunks to be the same size which gives all of the macros the same size and allows us to index + LEAF_ENTRY __jmpstub__$name + ;; rcx is the this pointer to the call being made + PUSH {r3} + PUSH {r1,r2} ; Push r1,r2 + ldr r2, [r0] + ;; r2 is the EEType pointer add the VTableOffset + slot_number * pointer size to get the vtable entry + ;; compare the that value to the address of the thunk being executed and if the values are equal then + ;; call to the resolver otherwise call the method + mov r1, EETypeVTableOffset + ($slot_number * PointerSize) + ldr r3, [r2,r1] + ; r3 is now the function pointer in the vtable + ldr r2,=__jmpstub__$name + cmp r2,r3 + beq JumpVTableResolver$name + mov r12,r3 ; Move the target function pointer to r12 before popping r2 and r3. We used r3 instead of r12 here so that + ; we could use the 2 byte thumb instructions and the whole thunk could fit in less than 32 bytes + POP {r1,r2,r3} + bx r12 +JumpVTableResolver$name + b __jmpstub__JumpToVTableResolver + LEAF_END __jmpstub__$name + MEND + + MACRO + VTableThunkDeclTen $slotnumberDecimal + VTableThunkDecl VTableSlot$slotnumberDecimal0,$slotnumberDecimal0 + VTableThunkDecl VTableSlot$slotnumberDecimal1,$slotnumberDecimal1 + VTableThunkDecl VTableSlot$slotnumberDecimal2,$slotnumberDecimal2 + VTableThunkDecl VTableSlot$slotnumberDecimal3,$slotnumberDecimal3 + VTableThunkDecl VTableSlot$slotnumberDecimal4,$slotnumberDecimal4 + VTableThunkDecl VTableSlot$slotnumberDecimal5,$slotnumberDecimal5 + VTableThunkDecl VTableSlot$slotnumberDecimal6,$slotnumberDecimal6 + VTableThunkDecl VTableSlot$slotnumberDecimal7,$slotnumberDecimal7 + VTableThunkDecl VTableSlot$slotnumberDecimal8,$slotnumberDecimal8 + VTableThunkDecl VTableSlot$slotnumberDecimal9,$slotnumberDecimal9 + MEND + + MACRO + VTableThunkDeclHundred $slotnumberPerHundred + VTableThunkDeclTen $slotnumberPerHundred0 + VTableThunkDeclTen $slotnumberPerHundred1 + VTableThunkDeclTen $slotnumberPerHundred2 + VTableThunkDeclTen $slotnumberPerHundred3 + VTableThunkDeclTen $slotnumberPerHundred4 + VTableThunkDeclTen $slotnumberPerHundred5 + VTableThunkDeclTen $slotnumberPerHundred6 + VTableThunkDeclTen $slotnumberPerHundred7 + VTableThunkDeclTen $slotnumberPerHundred8 + VTableThunkDeclTen $slotnumberPerHundred9 + MEND + + VTableThunkDeclHundred 0 + + END |