From 337547d1c997a11266c967e27ac7bc6c611b6372 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Sat, 11 Feb 2012 00:50:56 -0500
Subject: [PATCH] gc: make constant arith errors a little more friendly

Fixes #2804.

R=ken2
CC=golang-dev
https://golang.org/cl/5652067
---
 src/cmd/gc/const.c    |  2 +-
 src/cmd/gc/go.h       |  2 +-
 src/cmd/gc/go.y       |  2 +-
 src/cmd/gc/mparith1.c | 10 ++++-----
 src/cmd/gc/mparith2.c | 49 ++++++++++++++++++++++++++-----------------
 src/cmd/gc/mparith3.c | 10 ++++-----
 src/cmd/gc/y.tab.c    |  2 +-
 src/cmd/go/build.go   |  7 +++++++
 test/const2.go        |  4 ++++
 9 files changed, 55 insertions(+), 33 deletions(-)

diff --git a/src/cmd/gc/const.c b/src/cmd/gc/const.c
index 01c4f15b3f..550e7e4943 100644
--- a/src/cmd/gc/const.c
+++ b/src/cmd/gc/const.c
@@ -589,7 +589,7 @@ evconst(Node *n)
 
 	case TUP(OADD, CTINT):
 	case TUP(OADD, CTRUNE):
-		mpaddfixfix(v.u.xval, rv.u.xval);
+		mpaddfixfix(v.u.xval, rv.u.xval, 0);
 		break;
 	case TUP(OSUB, CTINT):
 	case TUP(OSUB, CTRUNE):
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 0fde506577..cd23b2f086 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -1049,7 +1049,7 @@ void	mpsubfltflt(Mpflt *a, Mpflt *b);
 /*
  *	mparith2.c
  */
-void	mpaddfixfix(Mpint *a, Mpint *b);
+void	mpaddfixfix(Mpint *a, Mpint *b, int);
 void	mpandfixfix(Mpint *a, Mpint *b);
 void	mpandnotfixfix(Mpint *a, Mpint *b);
 void	mpdivfract(Mpint *a, Mpint *b);
diff --git a/src/cmd/gc/go.y b/src/cmd/gc/go.y
index ccbb90f47b..ffd9b73737 100644
--- a/src/cmd/gc/go.y
+++ b/src/cmd/gc/go.y
@@ -2027,7 +2027,7 @@ hidden_constant:
 	{
 		if($2->val.ctype == CTRUNE && $4->val.ctype == CTINT) {
 			$$ = $2;
-			mpaddfixfix($2->val.u.xval, $4->val.u.xval);
+			mpaddfixfix($2->val.u.xval, $4->val.u.xval, 0);
 			break;
 		}
 		$$ = nodcplxlit($2->val, $4->val);
diff --git a/src/cmd/gc/mparith1.c b/src/cmd/gc/mparith1.c
index 2b7307e1a4..33fa90e2e0 100644
--- a/src/cmd/gc/mparith1.c
+++ b/src/cmd/gc/mparith1.c
@@ -72,7 +72,7 @@ void
 mpsubfixfix(Mpint *a, Mpint *b)
 {
 	mpnegfix(a);
-	mpaddfixfix(a, b);
+	mpaddfixfix(a, b, 0);
 	mpnegfix(a);
 }
 
@@ -90,7 +90,7 @@ mpaddcfix(Mpint *a, vlong c)
 	Mpint b;
 
 	mpmovecfix(&b, c);
-	mpaddfixfix(a, &b);
+	mpaddfixfix(a, &b, 0);
 }
 
 void
@@ -302,7 +302,7 @@ mpatoflt(Mpflt *a, char *as)
 				if(c >= '0' && c <= '9') {
 					ex = ex*10 + (c-'0');
 					if(ex > 1e8) {
-						yyerror("exponent out of range");
+						yyerror("constant exponent out of range: %s", as);
 						errorexit();
 					}
 					continue;
@@ -343,7 +343,7 @@ out:
 	return;
 
 bad:
-	yyerror("set ovf in mpatof");
+	yyerror("constant too large: %s", as);
 	mpmovecflt(a, 0.0);
 }
 
@@ -431,7 +431,7 @@ out:
 	return;
 
 bad:
-	yyerror("set ovf in mpatov: %s", as);
+	yyerror("constant too large: %s", as);
 	mpmovecfix(a, 0);
 }
 
diff --git a/src/cmd/gc/mparith2.c b/src/cmd/gc/mparith2.c
index 71cc29c99a..c802e4468a 100644
--- a/src/cmd/gc/mparith2.c
+++ b/src/cmd/gc/mparith2.c
@@ -121,7 +121,8 @@ mpcmp(Mpint *a, Mpint *b)
 	int i;
 
 	if(a->ovf || b->ovf) {
-		yyerror("ovf in cmp");
+		if(nsavederrors+nerrors == 0)
+			yyerror("ovf in cmp");
 		return 0;
 	}
 
@@ -190,13 +191,14 @@ mpshiftfix(Mpint *a, int s)
 /// implements fix arihmetic
 
 void
-mpaddfixfix(Mpint *a, Mpint *b)
+mpaddfixfix(Mpint *a, Mpint *b, int quiet)
 {
 	int i, c;
 	long x, *a1, *b1;
 
 	if(a->ovf || b->ovf) {
-		yyerror("ovf in mpaddxx");
+		if(nsavederrors+nerrors == 0)
+			yyerror("ovf in mpaddxx");
 		a->ovf = 1;
 		return;
 	}
@@ -218,8 +220,8 @@ mpaddfixfix(Mpint *a, Mpint *b)
 		*a1++ = x;
 	}
 	a->ovf = c;
-	if(a->ovf)
-		yyerror("set ovf in mpaddxx");
+	if(a->ovf && !quiet)
+		yyerror("constant addition overflow");
 
 	return;
 
@@ -266,7 +268,8 @@ mpmulfixfix(Mpint *a, Mpint *b)
 	Mpint s, q;
 
 	if(a->ovf || b->ovf) {
-		yyerror("ovf in mpmulfixfix");
+		if(nsavederrors+nerrors == 0)
+			yyerror("ovf in mpmulfixfix");
 		a->ovf = 1;
 		return;
 	}
@@ -290,7 +293,7 @@ mpmulfixfix(Mpint *a, Mpint *b)
 		x = *a1++;
 		for(j=0; j<Mpscale; j++) {
 			if(x & 1)
-				mpaddfixfix(&q, &s);
+				mpaddfixfix(&q, &s, 1);
 			mplsh(&s);
 			x >>= 1;
 		}
@@ -299,7 +302,7 @@ mpmulfixfix(Mpint *a, Mpint *b)
 	q.neg = a->neg ^ b->neg;
 	mpmovefixfix(a, &q);
 	if(a->ovf)
-		yyerror("set ovf in mpmulfixfix");
+		yyerror("constant multiplication overflow");
 }
 
 void
@@ -311,7 +314,8 @@ mpmulfract(Mpint *a, Mpint *b)
 	Mpint s, q;
 
 	if(a->ovf || b->ovf) {
-		yyerror("ovf in mpmulflt");
+		if(nsavederrors+nerrors == 0)
+			yyerror("ovf in mpmulflt");
 		a->ovf = 1;
 		return;
 	}
@@ -334,7 +338,7 @@ mpmulfract(Mpint *a, Mpint *b)
 		for(j=0; j<Mpscale; j++) {
 			x <<= 1;
 			if(x & Mpbase)
-				mpaddfixfix(&q, &s);
+				mpaddfixfix(&q, &s, 1);
 			mprsh(&s);
 		}
 	}
@@ -342,7 +346,7 @@ mpmulfract(Mpint *a, Mpint *b)
 	q.neg = a->neg ^ b->neg;
 	mpmovefixfix(a, &q);
 	if(a->ovf)
-		yyerror("set ovf in mpmulflt");
+		yyerror("constant multiplication overflow");
 }
 
 void
@@ -353,7 +357,8 @@ mporfixfix(Mpint *a, Mpint *b)
 
 	x = 0;
 	if(a->ovf || b->ovf) {
-		yyerror("ovf in mporfixfix");
+		if(nsavederrors+nerrors == 0)
+			yyerror("ovf in mporfixfix");
 		mpmovecfix(a, 0);
 		a->ovf = 1;
 		return;
@@ -388,7 +393,8 @@ mpandfixfix(Mpint *a, Mpint *b)
 
 	x = 0;
 	if(a->ovf || b->ovf) {
-		yyerror("ovf in mpandfixfix");
+		if(nsavederrors+nerrors == 0)
+			yyerror("ovf in mpandfixfix");
 		mpmovecfix(a, 0);
 		a->ovf = 1;
 		return;
@@ -423,7 +429,8 @@ mpandnotfixfix(Mpint *a, Mpint *b)
 
 	x = 0;
 	if(a->ovf || b->ovf) {
-		yyerror("ovf in mpandnotfixfix");
+		if(nsavederrors+nerrors == 0)
+			yyerror("ovf in mpandnotfixfix");
 		mpmovecfix(a, 0);
 		a->ovf = 1;
 		return;
@@ -458,7 +465,8 @@ mpxorfixfix(Mpint *a, Mpint *b)
 
 	x = 0;
 	if(a->ovf || b->ovf) {
-		yyerror("ovf in mporfixfix");
+		if(nsavederrors+nerrors == 0)
+			yyerror("ovf in mporfixfix");
 		mpmovecfix(a, 0);
 		a->ovf = 1;
 		return;
@@ -491,7 +499,8 @@ mplshfixfix(Mpint *a, Mpint *b)
 	vlong s;
 
 	if(a->ovf || b->ovf) {
-		yyerror("ovf in mporfixfix");
+		if(nsavederrors+nerrors == 0)
+			yyerror("ovf in mporfixfix");
 		mpmovecfix(a, 0);
 		a->ovf = 1;
 		return;
@@ -512,7 +521,8 @@ mprshfixfix(Mpint *a, Mpint *b)
 	vlong s;
 
 	if(a->ovf || b->ovf) {
-		yyerror("ovf in mprshfixfix");
+		if(nsavederrors+nerrors == 0)
+			yyerror("ovf in mprshfixfix");
 		mpmovecfix(a, 0);
 		a->ovf = 1;
 		return;
@@ -542,7 +552,8 @@ mpgetfix(Mpint *a)
 	vlong v;
 
 	if(a->ovf) {
-		yyerror("constant overflow");
+		if(nsavederrors+nerrors == 0)
+			yyerror("constant overflow");
 		return 0;
 	}
 
@@ -605,7 +616,7 @@ mpdivmodfixfix(Mpint *q, Mpint *r, Mpint *n, Mpint *d)
 		r->ovf = 1;
 		n->neg = ns;
 		d->neg = ds;
-		yyerror("set ovf in mpdivmodfixfix");
+		yyerror("constant division overflow");
 		return;
 	}
 
diff --git a/src/cmd/gc/mparith3.c b/src/cmd/gc/mparith3.c
index 0c6c5a03b9..f8344c9b4e 100644
--- a/src/cmd/gc/mparith3.c
+++ b/src/cmd/gc/mparith3.c
@@ -89,17 +89,17 @@ mpaddfltflt(Mpflt *a, Mpflt *b)
 		// a is larger, shift b right
 		mpmovefltflt(&c, b);
 		mpshiftfix(&c.val, -s);
-		mpaddfixfix(&a->val, &c.val);
+		mpaddfixfix(&a->val, &c.val, 0);
 		goto out;
 	}
 	if(s < 0) {
 		// b is larger, shift a right
 		mpshiftfix(&a->val, s);
 		a->exp -= s;
-		mpaddfixfix(&a->val, &b->val);
+		mpaddfixfix(&a->val, &b->val, 0);
 		goto out;
 	}
-	mpaddfixfix(&a->val, &b->val);
+	mpaddfixfix(&a->val, &b->val, 0);
 
 out:
 	mpnorm(a);
@@ -153,7 +153,7 @@ mpdivfltflt(Mpflt *a, Mpflt *b)
 		a->exp = 0;
 		a->val.neg = 0;
 		a->val.ovf = 1;
-		yyerror("mpdivfltflt divide by zero");
+		yyerror("constant division by zero");
 		return;
 	}
 
@@ -185,7 +185,7 @@ mpgetflt(Mpflt *a)
 	uvlong v, vm;
 	double f;
 
-	if(a->val.ovf)
+	if(a->val.ovf && nsavederrors+nerrors == 0)
 		yyerror("mpgetflt ovf");
 
 	s = sigfig(a);
diff --git a/src/cmd/gc/y.tab.c b/src/cmd/gc/y.tab.c
index d2aaa05046..2772575087 100644
--- a/src/cmd/gc/y.tab.c
+++ b/src/cmd/gc/y.tab.c
@@ -5188,7 +5188,7 @@ yyreduce:
     {
 		if((yyvsp[(2) - (5)].node)->val.ctype == CTRUNE && (yyvsp[(4) - (5)].node)->val.ctype == CTINT) {
 			(yyval.node) = (yyvsp[(2) - (5)].node);
-			mpaddfixfix((yyvsp[(2) - (5)].node)->val.u.xval, (yyvsp[(4) - (5)].node)->val.u.xval);
+			mpaddfixfix((yyvsp[(2) - (5)].node)->val.u.xval, (yyvsp[(4) - (5)].node)->val.u.xval, 0);
 			break;
 		}
 		(yyval.node) = nodcplxlit((yyvsp[(2) - (5)].node)->val, (yyvsp[(4) - (5)].node)->val);
diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index 0956a35eae..da046eedbc 100644
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -671,6 +671,13 @@ func (b *builder) install(a *action) error {
 		}
 	}
 
+	// remove object dir to keep the amount of
+	// garbage down in a large build.  On an operating system
+	// with aggressive buffering, cleaning incrementally like
+	// this keeps the intermediate objects from hitting the disk.
+	defer os.RemoveAll(a1.objdir)
+	defer os.Remove(a1.target)
+
 	return b.copyFile(a.target, a1.target, perm)
 }
 
diff --git a/test/const2.go b/test/const2.go
index bea1b99125..b0837354ab 100644
--- a/test/const2.go
+++ b/test/const2.go
@@ -10,3 +10,7 @@ const (
 	A int = 1
 	B byte;	// ERROR "type without expr|expected .=."
 )
+
+const LargeA = 1000000000000000000
+const LargeB = LargeA * LargeA * LargeA
+const LargeC = LargeB * LargeB * LargeB  // ERROR "constant multiplication overflow"
-- 
2.50.0