first stub for softfloats, intercepts float instructions and skips

        them in the stream.

R=rsc
https://golang.org/cl/174052

6 files changed, 87 insertions, 3 deletions

diff --git a/src/cmd/5l/Makefile b/src/cmd/5l/Makefile
index be866b87a4..aa175d14c6 100644
--- a/src/cmd/5l/Makefile
+++ b/src/cmd/5l/Makefile
@@ -17,6 +17,7 @@ OFILES=\
 	optab.$O\
 	pass.$O\
 	thumb.$O\
+	softfloat.$O\
 	span.$O\
 	go.$O\
 
diff --git a/src/cmd/5l/l.h b/src/cmd/5l/l.h
index 05a20bad36..ba2de0a0f2 100644
--- a/src/cmd/5l/l.h
+++ b/src/cmd/5l/l.h
@@ -451,6 +451,7 @@ void	putsymb(char*, int, int32, int);
 int32	regoff(Adr*);
 int	relinv(int);
 int32	rnd(int32, int32);
+void	softfloat(void);
 void	span(void);
 void	strnput(char*, int);
 void	undef(void);
diff --git a/src/cmd/5l/obj.c b/src/cmd/5l/obj.c
index 805d39544e..8fd39c2919 100644
--- a/src/cmd/5l/obj.c
+++ b/src/cmd/5l/obj.c
@@ -71,6 +71,12 @@ isobjfile(char *f)
 	return v;
 }
 
+static char*
+linkername[] =
+{
+	"runtime·softfloat",
+};
+
 void
 usage(void)
 {
@@ -81,7 +87,7 @@ usage(void)
 void
 main(int argc, char *argv[])
 {
-	int c;
+	int c, i;
 
 	Binit(&bso, 1, OWRITE);
 	cout = -1;
@@ -257,6 +263,10 @@ main(int argc, char *argv[])
 	if(!debug['l'])
 		loadlib();
 
+	// mark some functions that are only referenced after linker code editing
+	// TODO(kaib): this doesn't work, the prog can't be found in runtime
+	for(i=0; i<nelem(linkername); i++)
+		mark(lookup(linkername[i], 0));
 	deadcode();
 
 	firstp = firstp->link;
@@ -294,6 +304,7 @@ main(int argc, char *argv[])
 	follow();
 	if(firstp == P)
 		goto out;
+	softfloat();
 	noops();
 	span();
 	asmb();
diff --git a/src/cmd/5l/softfloat.c b/src/cmd/5l/softfloat.c
new file mode 100644
index 0000000000..f5a146feb0
--- /dev/null
+++ b/src/cmd/5l/softfloat.c
@@ -0,0 +1,70 @@
+// Copyright 2009 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.
+
+#define	EXTERN
+#include	"l.h"
+
+void
+softfloat()
+{
+	Prog *p, *prev, *psfloat;
+	Sym *symsfloat;
+	int wasfloat;
+	
+	symsfloat = lookup("_sfloat", 0);
+	psfloat = P;
+	if(symsfloat->type == STEXT)
+	for(p = firstp; p != P; p = p->link) {
+		if(p->as == ATEXT) {
+			if(p->from.sym == symsfloat) {
+				psfloat = p;
+				break;
+			}
+		}
+	}
+
+	wasfloat = 0;
+	p = firstp;
+	prev = P;
+	for(p = firstp; p != P; p = p->link) {
+		switch(p->as) {
+		case AMOVWD:
+		case AMOVWF:
+		case AMOVDW:
+		case AMOVFW:
+		case AMOVFD:
+		case AMOVDF:
+		case AMOVF:
+		case AMOVD:
+		case ACMPF:
+		case ACMPD:
+		case AADDF:
+		case AADDD:
+		case ASUBF:
+		case ASUBD:
+		case AMULF:
+		case AMULD:
+		case ADIVF:
+		case ADIVD:
+			if (psfloat == P)
+				diag("floats used with _sfloat not defined");
+			if (!wasfloat) {
+				if (prev == P)
+					diag("float instruction without predecessor TEXT");
+				// BL		_sfloat(SB)
+				prev = appendp(prev);
+				prev->as = ABL;
+ 				prev->to.type = D_BRANCH;
+				prev->to.sym = symsfloat;
+				prev->cond = psfloat;
+				
+				wasfloat = 1;
+			}
+			break;
+		default:
+			wasfloat = 0;
+		}
+		prev = p;
+	}
+}
diff --git a/src/cmd/ld/go.c b/src/cmd/ld/go.c
index 8f0e66d330..9a9346c1f2 100644
--- a/src/cmd/ld/go.c
+++ b/src/cmd/ld/go.c
@@ -364,7 +364,6 @@ err:
 	nerrors++;
 }
 
-static void mark(Sym*);
 static int markdepth;
 
 static void
@@ -408,7 +407,7 @@ marktext(Prog *p)
 	markdepth--;
 }
 
-static void
+void
 mark(Sym *s)
 {
 	if(s == S || s->reachable)
diff --git a/src/cmd/ld/lib.h b/src/cmd/ld/lib.h
index 0ae4106b8a..4a300ac4e9 100644
--- a/src/cmd/ld/lib.h
+++ b/src/cmd/ld/lib.h
@@ -77,6 +77,8 @@ void	usage(void);
 void	ldobj1(Biobuf *f, int64 len, char *pn);
 void	ldobj(Biobuf*, int64, char*);
 void	ldpkg(Biobuf*, int64, char*);
+void	mark(Sym *s);
+
 
 int	pathchar(void);
 void*	mal(uint32);