code review 3733046: new cgo windows port.

src/cmd/ld/ldpe.c

Index: src/cmd/ld/ldpe.c
===================================================================
new file mode 100644
--- /dev/null
+++ b/src/cmd/ld/ldpe.c
@@ -0,0 +1,404 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include	"l.h"
+#include	"lib.h"
+#include	"../ld/pe.h"
+
+#define IMAGE_SCN_MEM_DISCARDABLE 0x2000000
+
+#define IMAGE_SYM_UNDEFINED	0
+#define IMAGE_SYM_ABSOLUTE (-1)
+#define IMAGE_SYM_DEBUG	(-2)
+#define IMAGE_SYM_TYPE_NULL 0
+#define IMAGE_SYM_TYPE_VOID 1
+#define IMAGE_SYM_TYPE_CHAR 2
+#define IMAGE_SYM_TYPE_SHORT 3
+#define IMAGE_SYM_TYPE_INT 4
+#define IMAGE_SYM_TYPE_LONG 5
+#define IMAGE_SYM_TYPE_FLOAT 6
+#define IMAGE_SYM_TYPE_DOUBLE 7
+#define IMAGE_SYM_TYPE_STRUCT 8
+#define IMAGE_SYM_TYPE_UNION 9
+#define IMAGE_SYM_TYPE_ENUM 10
+#define IMAGE_SYM_TYPE_MOE 11
+#define IMAGE_SYM_TYPE_BYTE 12
+#define IMAGE_SYM_TYPE_WORD 13
+#define IMAGE_SYM_TYPE_UINT 14
+#define IMAGE_SYM_TYPE_DWORD 15
+#define IMAGE_SYM_TYPE_PCODE 32768
+#define IMAGE_SYM_DTYPE_NULL 0
+#define IMAGE_SYM_DTYPE_POINTER 0x10
+#define IMAGE_SYM_DTYPE_FUNCTION 0x20
+#define IMAGE_SYM_DTYPE_ARRAY 0x30
+#define IMAGE_SYM_CLASS_END_OF_FUNCTION	(-1)
+#define IMAGE_SYM_CLASS_NULL 0
+#define IMAGE_SYM_CLASS_AUTOMATIC 1
+#define IMAGE_SYM_CLASS_EXTERNAL 2
+#define IMAGE_SYM_CLASS_STATIC 3
+#define IMAGE_SYM_CLASS_REGISTER 4
+#define IMAGE_SYM_CLASS_EXTERNAL_DEF 5
+#define IMAGE_SYM_CLASS_LABEL 6
+#define IMAGE_SYM_CLASS_UNDEFINED_LABEL 7
+#define IMAGE_SYM_CLASS_MEMBER_OF_STRUCT 8
+#define IMAGE_SYM_CLASS_ARGUMENT 9
+#define IMAGE_SYM_CLASS_STRUCT_TAG 10
+#define IMAGE_SYM_CLASS_MEMBER_OF_UNION 11
+#define IMAGE_SYM_CLASS_UNION_TAG 12
+#define IMAGE_SYM_CLASS_TYPE_DEFINITION 13
+#define IMAGE_SYM_CLASS_UNDEFINED_STATIC 14
+#define IMAGE_SYM_CLASS_ENUM_TAG 15
+#define IMAGE_SYM_CLASS_MEMBER_OF_ENUM 16
+#define IMAGE_SYM_CLASS_REGISTER_PARAM 17
+#define IMAGE_SYM_CLASS_BIT_FIELD 18
+#define IMAGE_SYM_CLASS_FAR_EXTERNAL 68 /* Not in PECOFF v8 spec */
+#define IMAGE_SYM_CLASS_BLOCK 100
+#define IMAGE_SYM_CLASS_FUNCTION 101
+#define IMAGE_SYM_CLASS_END_OF_STRUCT 102
+#define IMAGE_SYM_CLASS_FILE 103
+#define IMAGE_SYM_CLASS_SECTION 104
+#define IMAGE_SYM_CLASS_WEAK_EXTERNAL 105
+#define IMAGE_SYM_CLASS_CLR_TOKEN 107
+
+#define IMAGE_REL_I386_ABSOLUTE	0x0000
+#define IMAGE_REL_I386_DIR16	0x0001
+#define IMAGE_REL_I386_REL16	0x0002
+#define IMAGE_REL_I386_DIR32	0x0006
+#define IMAGE_REL_I386_DIR32NB	0x0007
+#define IMAGE_REL_I386_SEG12	0x0009
+#define IMAGE_REL_I386_SECTION	0x000A
+#define IMAGE_REL_I386_SECREL	0x000B
+#define IMAGE_REL_I386_TOKEN	0x000C
+#define IMAGE_REL_I386_SECREL7	0x000D
+#define IMAGE_REL_I386_REL32	0x0014
+
+typedef struct PeSym PeSym;
+typedef struct PeSect PeSect;
+typedef struct PeObj PeObj;
+
+struct PeSym {
+	char* name;
+	uint32 value;
+	uint16 sectnum;
+	uint16 type;
+	uint8 sclass;
+	uint8 aux;
+	Sym* sym;
+};
+
+struct PeSect {
+	char* name;
+	uchar* base;
+	uint64 size;
+	Sym* sym;
+	IMAGE_SECTION_HEADER sh;
+};
+
+struct PeObj {
+	Biobuf	*f;
+	char	*name;
+	uint32 base;
+	
+	PeSect	*sect;
+	uint	nsect;
+	PeSym	*pesym;
+	uint npesym;
+	
+	IMAGE_FILE_HEADER fh;
+	char* snames;
+};
+
+static int map(PeObj *obj, PeSect *sect);
+static int readsym(PeObj *obj, int i, PeSym **sym);
+
+void
+ldpe(Biobuf *f, char *pkg, int64 len, char *pn)
+{
+	char *name;
+	int32 base;
+	int i, j, l, numaux;
+	PeObj *obj;
+	PeSect *sect, *rsect;
+	IMAGE_SECTION_HEADER sh;
+	uchar symbuf[18];
+	Sym *s;
+	Reloc *r, *rp;
+	PeSym *sym;
+	
+	if(debug['v'])
+		Bprint(&bso, "%5.2f ldpe %s\n", cputime(), pn);
+	
+	version++;
+	base = Boffset(f);
+	
+	obj = mal(sizeof *obj);
+	obj->f = f;
+	obj->base = base;
+	obj->name = pn;
+	// read header
+	if(Bread(f, &obj->fh, sizeof obj->fh) != sizeof obj->fh)
+		goto bad;
+	// load section list
+	obj->sect = mal(obj->fh.NumberOfSections*sizeof obj->sect[0]);
+	obj->nsect = obj->fh.NumberOfSections;
+	for(i=0; i < obj->fh.NumberOfSections; i++) {
+		if(Bread(f, &obj->sect[i].sh, sizeof sh) != sizeof sh)
+			goto bad;
+		obj->sect[i].size = obj->sect[i].sh.SizeOfRawData;
+		obj->sect[i].name = (char*)obj->sect[i].sh.Name;
+		// TODO return error if found .cormeta .rsrc
+	}
+	// load string table
+	Bseek(f, base+obj->fh.PointerToSymbolTable+18*obj->fh.NumberOfSymbols, 0);
+	if(Bread(f, &l, sizeof l) != sizeof l) 
+		goto bad;
+	obj->snames = mal(l);
+	Bseek(f, base+obj->fh.PointerToSymbolTable+18*obj->fh.NumberOfSymbols, 0);
+	if(Bread(f, obj->snames, l) != l)
+		goto bad;
+	// read symbols
+	obj->pesym = mal(obj->fh.NumberOfSymbols*sizeof obj->pesym[0]);
+	obj->npesym = obj->fh.NumberOfSymbols;
+	Bseek(f, base+obj->fh.PointerToSymbolTable, 0);
+	for(i=0; i<obj->fh.NumberOfSymbols; i+=numaux+1) {
+		Bseek(f, base+obj->fh.PointerToSymbolTable+sizeof(symbuf)*i, 0);
+		if(Bread(f, symbuf, sizeof symbuf) != sizeof symbuf)
+			goto bad;
+		
+		if((symbuf[0] == 0) && (symbuf[1] == 0) &&
+			 (symbuf[2] == 0) && (symbuf[3] == 0)) {
+			l = le32(&symbuf[4]);
+			obj->pesym[i].name = (char*)&obj->snames[l];
+		} else {
+			obj->pesym[i].name = strdup((char*)symbuf);
+		}
+		obj->pesym[i].value = le32(&symbuf[8]);
+		obj->pesym[i].sectnum = le16(&symbuf[12]);
+		obj->pesym[i].sclass = symbuf[16];
+		obj->pesym[i].aux = symbuf[17];
+		obj->pesym[i].type = le16(&symbuf[14]);
+		numaux = obj->pesym[i].aux; 
+		if (numaux < 0) 
+			numaux = 0;
+	}
+	// create symbols for mapped sections
+	for(i=0; i<obj->nsect; i++) {
+		sect = &obj->sect[i];
+		if(sect->sh.Characteristics&IMAGE_SCN_MEM_DISCARDABLE)
+			continue;
+		if(map(obj, sect) < 0)
+			goto bad;
+		
+		name = smprint("%s(%s)", pn, sect->name);
+		s = lookup(name, version);
+		free(name);
+		switch(sect->sh.Characteristics&(IMAGE_SCN_CNT_UNINITIALIZED_DATA|IMAGE_SCN_CNT_INITIALIZED_DATA|
+			IMAGE_SCN_MEM_READ|IMAGE_SCN_MEM_WRITE|IMAGE_SCN_CNT_CODE|IMAGE_SCN_MEM_EXECUTE)) {
+			case IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_MEM_READ: //.rdata
+				s->type = SRODATA;
+				break;
+			case IMAGE_SCN_CNT_UNINITIALIZED_DATA|IMAGE_SCN_MEM_READ|IMAGE_SCN_MEM_WRITE: //.bss
+			case IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_MEM_READ|IMAGE_SCN_MEM_WRITE: //.data
+				s->type = SDATA;
+				break;
+			case IMAGE_SCN_CNT_CODE|IMAGE_SCN_MEM_EXECUTE|IMAGE_SCN_MEM_READ: //.text
+				s->type = STEXT;
+				break;
+			default:
+				werrstr("unexpected flags for PE section %s", sect->name);
+				goto bad;
+		}
+		s->p = sect->base;
+		s->np = sect->size;
+		s->size = sect->size;
+		if(s->type == STEXT) {
+			if(etextp)
+				etextp->next = s;
+			else
+				textp = s;
+			etextp = s;
+		}
+		sect->sym = s;
+	}
+	
+	// load relocations
+	for(i=0; i<obj->nsect; i++) {
+		rsect = &obj->sect[i];
+		if(rsect->sym == 0 || rsect->sh.NumberOfRelocations == 0)
+			continue;
+		if(rsect->sh.Characteristics&IMAGE_SCN_MEM_DISCARDABLE)
+			continue;
+		r = mal(rsect->sh.NumberOfRelocations*sizeof r[0]);
+		Bseek(f, obj->base+rsect->sh.PointerToRelocations, 0);
+		for(j=0; j<rsect->sh.NumberOfRelocations; j++) {
+			rp = &r[j];
+			if(Bread(f, symbuf, 10) != 10)
+				goto bad;
+			
+			uint32 rva, symindex;
+			uint16 type;
+			rva = le32(&symbuf[0]);
+			symindex = le32(&symbuf[4]);
+			type = le16(&symbuf[8]);
+			if(readsym(obj, symindex, &sym) < 0)
+				goto bad;
+			if(sym->sym == nil) {
+				werrstr("reloc of invalid sym %s idx=%d type=%d", sym->name, symindex, sym->type);
+				goto bad;
+			}
+			rp->sym = sym->sym;
+			rp->siz = 4;
+			rp->off = rva;
+			switch(type) {
+				default:
+					diag("%s: unknown relocation type %d;", pn, type);
+				case IMAGE_REL_I386_REL32:
+					rp->type = D_PCREL;
+					rp->add = 0;
+					break;
+				case IMAGE_REL_I386_DIR32:
+					rp->type = D_ADDR;
+					// load addend from image
+					rp->add = le32(rsect->base+rp->off);
+					break;
+			}
+		}
+		qsort(r, rsect->sh.NumberOfRelocations, sizeof r[0], rbyoff);
+		
+		s = rsect->sym;
+		s->r = r;
+		s->nr = rsect->sh.NumberOfRelocations;
+	}
+	
+	// enter sub-symbols into symbol table.
+	// frist 2 entry is file name.
+	for(i=2; i<obj->npesym; i++) {
+		if(obj->pesym[i].name == 0)
+			continue;
+		if(obj->pesym[i].name[0] == '.') //skip section
+			continue;
+		if(obj->pesym[i].sectnum > 0) {
+			sect = &obj->sect[obj->pesym[i].sectnum-1];
+			if(sect->sym == 0)
+				continue;
+		}
+		if(readsym(obj, i, &sym) < 0)
+			goto bad;
+	
+		s = sym->sym;
+		if(sym->sectnum == 0) {// extern
+			if(s->type == SDYNIMPORT)
+				s->plt = -2; // flag for dynimport in PE object files.
+			continue;
+		} else if (sym->sectnum > 0) {
+			sect = &obj->sect[sym->sectnum-1];
+			if(sect->sym == 0)
+				diag("%s: %s sym == 0!", pn, s->name);
+		} else {
+			diag("%s: %s sectnum <0!", pn, s->name, sym->sectnum);
+		}
+
+		s->sub = sect->sym->sub;
+		sect->sym->sub = s;
+		s->type = sect->sym->type | SSUB;
+		s->value = sym->value;
+		s->size = 4;
+		s->outer = sect->sym;
+		if(sect->sym->type == STEXT) {
+			Prog *p;
+	
+			if(s->text != P)
+				diag("%s: duplicate definition of %s", pn, s->name);
+			// build a TEXT instruction with a unique pc
+			// just to make the rest of the linker happy.
+			p = prg();
+			p->as = ATEXT;
+			p->from.type = D_EXTERN;
+			p->from.sym = s;
+			p->textflag = 7;
+			p->to.type = D_CONST;
+			p->link = nil;
+			p->pc = pc++;
+			s->text = p;
+	
+			etextp->next = s;
+			etextp = s;
+		}
+	}
+
+	return;
+bad:
+	diag("%s: malformed pe file: %r", pn);
+}
+
+static int
+map(PeObj *obj, PeSect *sect)
+{
+	if(sect->base != nil)
+		return 0;
+
+	sect->base = mal(sect->sh.SizeOfRawData);
+	werrstr("short read");
+	if(Bseek(obj->f, obj->base+sect->sh.PointerToRawData, 0) < 0 || 
+			Bread(obj->f, sect->base, sect->sh.SizeOfRawData) != sect->sh.SizeOfRawData)
+		return -1;
+	
+	return 0;
+}
+
+static int
+readsym(PeObj *obj, int i, PeSym **y)
+{
+	Sym *s;
+	PeSym *sym;
+	char *name, *p;
+
+	if(i >= obj->npesym || i < 0) {
+		werrstr("invalid pe symbol index");
+		return -1;
+	}
+
+	sym = &obj->pesym[i];
+	*y = sym;
+	s = nil;
+	
+	name = sym->name;
+	if(sym->sclass == IMAGE_SYM_CLASS_STATIC && sym->value == 0) // section
+		name = obj->sect[sym->sectnum-1].sym->name;
+	if(strncmp(sym->name, "__imp__", 6) == 0)
+		name = &sym->name[7]; // __imp__Name => Name
+	else if(sym->name[0] == '_') 
+		name = &sym->name[1]; // _Name => Name
+	// remove last @XXX
+	p = strchr(name, '@');
+	if(p)
+		*p = 0;
+	
+	switch(sym->type) {
+	default:
+		werrstr("%s: invalid symbol type %d", sym->name, sym->type);
+		return -1;
+	case IMAGE_SYM_DTYPE_FUNCTION:
+	case IMAGE_SYM_DTYPE_NULL:
+		switch(sym->sclass) {
+		case IMAGE_SYM_CLASS_EXTERNAL: //global
+			s = lookup(name, 0);
+			break;
+		case IMAGE_SYM_CLASS_NULL:
+		case IMAGE_SYM_CLASS_STATIC:
+			s = lookup(name, version);
+			break;
+		default:
+			werrstr("%s: invalid symbol binding %d", sym->name, sym->sclass);
+			return -1;
+		}
+		break;
+	}
+
+	if(s != nil && s->type == 0 && !(sym->sclass == IMAGE_SYM_CLASS_STATIC && sym->value == 0))
+		s->type = SXREF;
+	sym->sym = s;
+
+	return 0;
+}