compile_c.rb in metasm-1.0.4

- old
+ new

@@ -30,10 +30,12 @@
 		attr_accessor :bound
 		# list of reg values that are used as func args in current ABI
 		attr_accessor :regargs
 		# stack space reserved for subfunction in ABI
 		attr_accessor :args_space
+		# ensure stack is 16byte aligned before calls
+		attr_accessor :stack_align16
 		# list of reg values that are not kept across function call
 		attr_accessor :abi_flushregs_call
 		# list of regs we can trash without restoring them
 		attr_accessor :abi_trashregs
 
@@ -50,10 +52,11 @@
 			@used = [4]	# rsp is always in use
 			@inuse = []
 			@bound = {}
 			@regargs = []
 			@args_space = 0
+			@stack_align16 = true
 			@abi_flushregs_call = [0, 1, 2, 6, 7, 8, 9, 10, 11]
 			@abi_trashregs = @abi_flushregs_call.dup
 		end
 	end
 
@@ -489,11 +492,13 @@
 					case r
 					when Reg
 						unuse l
 						l = Address.new(l.modrm.dup)
 						inuse l
-						if l.modrm.b
+						if (l.modrm.b and l.modrm.b.val == 16) or (l.modrm.i and l.modrm.i.val == 16)
+							# cannot encode [rip+reg+imm]
+						elsif l.modrm.b
 							if not l.modrm.i or (l.modrm.i.val == r.val and l.modrm.s == 1)
 								l.modrm.i = r
 								l.modrm.s = (l.modrm.s || 0) + 1
 								unuse r
 								return l
@@ -644,19 +649,19 @@
 			@state.used.delete reg
 		}
 
 		stackargs = expr.rexpr.zip(regargsmask).map { |a, r| a if not r }.compact
 
-		# preserve 16byte stack align under windows
-		stackalign = true if @state.args_space > 0 and (stackargs + backup).length & 1 == 1
+		stackalign = true if @state.stack_align16 and (stackargs + backup).length & 1 == 1
 		instr 'sub', Reg.new(4, @cpusz), Expression[8] if stackalign
 
 		stackargs.reverse_each { |arg|
 			raise 'arg unhandled' if not arg.type.integral? or arg.type.pointer?
 			a = c_cexpr_inner(arg)
-			a = resolve_address a if a.kind_of? Address
-			a = make_volatile(a, arg.type) if a.kind_of? ModRM and arg.type.name != :__int64
+			a = resolve_address a if a.kind_of?(Address)
+			a = make_volatile(a, arg.type) if (a.kind_of?(ModRM) and arg.type.name != :__int64) or
+							  (a.kind_of?(Expression) and (va = a.reduce) and (not va.kind_of?(::Integer) or va < -0x8000_0000 or va > 0x7fff_ffff))
 			unuse a
 			instr 'push', a
 		}
 
 		regargs_unuse = []
@@ -980,12 +985,11 @@
 		localspc = @state.offset.values.grep(::Integer).max
 		return if @state.func.attributes.to_a.include? 'naked'
 		@state.dirty -= @state.abi_trashregs
 		if localspc
 			localspc = (localspc + 7) / 8 * 8
-			if @state.args_space > 0 and (localspc/8 + @state.dirty.length) & 1 == 1
-				# ensure 16-o stack align on windows
+			if @state.stack_align16 and (localspc/8 + @state.dirty.length) & 1 == 1
 				localspc += 8
 			end
 			ebp = @state.saved_rbp
 			esp = Reg.new(4, ebp.sz)
 			instr 'push', ebp
@@ -1000,11 +1004,11 @@
 				else next
 				end
 				v = findvar(a)
 				instr 'mov', v, Reg.new(r, v.sz)
 			}
-		elsif @state.args_space > 0 and @state.dirty.length & 1 == 0
+		elsif @state.stack_align16 and @state.dirty.length & 1 == 0
 			instr 'sub', Reg.new(4, @cpusz), Expression[8]
 		end
 		@state.dirty.each { |reg|
 			instr 'push', Reg.new(reg, @cpusz)
 		}
@@ -1016,10 +1020,10 @@
 			instr 'pop', Reg.new(reg, @cpusz)
 		}
 		if ebp = @state.saved_rbp
 			instr 'mov', Reg.new(4, ebp.sz), ebp
 			instr 'pop', ebp
-		elsif @state.args_space > 0 and @state.dirty.length & 1 == 0
+		elsif @state.stack_align16 and @state.dirty.length & 1 == 0
 			instr 'add', Reg.new(4, @cpusz), Expression[8]
 		end
 		instr 'ret'
 	end
 