Add function to print strings from generated code

common.mk

@@ -151,6 +151,7 @@ COMMONOBJS    = array.$(OBJEXT) \
 		vm_sync.$(OBJEXT) \
 		vm_trace.$(OBJEXT) \
 		ujit_asm.$(OBJEXT) \
+		ujit_utils.$(OBJEXT) \
 		ujit_compile.$(OBJEXT) \
 		$(COROUTINE_OBJ) \
 		$(DTRACE_OBJ) \

ujit_asm.c

@@ -1084,15 +1084,13 @@ void jmp8(CodeBlock cb, int8_t offset)
 }
 */
 
-/*
-/// jmp - Jump with relative 32-bit offset
-void jmp32(CodeBlock cb, int32_t offset)
+// jmp - Jump with relative 32-bit offset
+void jmp32(codeblock_t* cb, int32_t offset)
 {
-    cb.writeASM("jmp", ((offset > 0)? "+":"-") ~ to!string(offset));
-    cb.writeByte(JMP_REL32_OPCODE);
-    cb.writeInt(offset, 32);
+    //cb.writeASM("jmp", ((offset > 0)? "+":"-") ~ to!string(offset));
+    cb_write_byte(cb, 0xE9);
+    cb_write_int(cb, offset, 32);
 }
-*/
 
 /// lea - Load Effective Address
 void lea(codeblock_t* cb, x86opnd_t dst, x86opnd_t src)

ujit_asm.h

@@ -265,6 +265,7 @@ void js(codeblock_t* cb, size_t label_idx);
 void jz(codeblock_t* cb, size_t label_idx);
 void jmp(codeblock_t* cb, size_t label_idx);
 void jmp_rm(codeblock_t* cb, x86opnd_t opnd);
+void jmp32(codeblock_t* cb, int32_t offset);
 void lea(codeblock_t* cb, x86opnd_t dst, x86opnd_t src);
 void mov(codeblock_t* cb, x86opnd_t dst, x86opnd_t src);
 void neg(codeblock_t* cb, x86opnd_t opnd);

ujit_compile.c

@@ -7,8 +7,10 @@
 #include "insns_info.inc"
 #include "ujit_compile.h"
 #include "ujit_asm.h"
+#include "ujit_utils.h"
 
 // TODO: give ujit_examples.h some more meaningful file name
+// eg ujit_hook.h
 #include "ujit_examples.h"
 
 // Code generation context

ujit_utils.c

@@ -0,0 +1,96 @@
+#include <stdio.h>
+#include <string.h>
+#include "ujit_utils.h"
+#include "ujit_asm.h"
+
+// Save caller-save registers on the stack before a C call
+void push_regs(codeblock_t* cb)
+{
+    push(cb, RAX);
+    push(cb, RCX);
+    push(cb, RDX);
+    push(cb, RSI);
+    push(cb, RDI);
+    push(cb, R8);
+    push(cb, R9);
+    push(cb, R10);
+    push(cb, R11);
+    pushfq(cb);
+}
+
+// Restore caller-save registers from the after a C call
+void pop_regs(codeblock_t* cb)
+{
+    popfq(cb);
+    pop(cb, R11);
+    pop(cb, R10);
+    pop(cb, R9);
+    pop(cb, R8);
+    pop(cb, RDI);
+    pop(cb, RSI);
+    pop(cb, RDX);
+    pop(cb, RCX);
+    pop(cb, RAX);
+}
+
+static void print_str_fn(const char* str)
+{
+    printf("%s", str);
+}
+
+/*
+void printInt(CodeBlock as, X86Opnd opnd)
+{
+    extern (C) void printIntFn(int64_t v)
+    {
+        writefln("%s", v);
+    }
+
+    size_t opndSz;
+    if (opnd.isImm)
+        opndSz = 64;
+    else if (opnd.isGPR)
+        opndSz = opnd.reg.size;
+    else if (opnd.isMem)
+        opndSz = opnd.mem.size;
+    else
+        assert (false);
+
+    as.pushRegs();
+
+    if (opndSz < 64)
+        as.movsx(cargRegs[0].opnd(64), opnd);
+    else
+        as.mov(cargRegs[0].opnd(64), opnd);
+
+    // Call the print function
+    as.ptr(scrRegs[0], &printIntFn);
+    as.call(scrRegs[0]);
+
+    as.popRegs();
+}
+*/
+
+// Print a constant string to stdout
+void print_str(codeblock_t* cb, const char* str)
+{
+    //as.comment("printStr(\"" ~ str ~ "\")");
+    size_t len = strlen(str);
+
+    push_regs(cb);
+
+    // Load the string address and jump over the string data
+    lea(cb, RDI, mem_opnd(8, RIP, 5));
+    jmp32(cb, (int32_t)len + 1);
+
+    // Write the string chars and a null terminator
+    for (size_t i = 0; i < len; ++i)
+        cb_write_byte(cb, (uint8_t)str[i]);
+    cb_write_byte(cb, 0);
+
+    // Call the print function
+    mov(cb, RAX, const_ptr_opnd(&print_str_fn));
+    call(cb, RAX);
+
+    pop_regs(cb);
+}

ujit_utils.h

@@ -0,0 +1,13 @@
+#ifndef UJIT_UTILS_H
+#define UJIT_UTILS_H 1
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include "ujit_asm.h"
+
+void push_regs(codeblock_t* cb);
+void pop_regs(codeblock_t* cb);
+void print_str(codeblock_t* cb, const char* str);
+
+#endif // #ifndef UJIT_UTILS_H