Workaround incorrect constant folding of subnormals in javac when the FPU

does not handle subnormal arithmetic, like on ARM in Flush-to-zero mode.
These workarounds avoid underflow conditions during the bootstrap so the
JDK can correctly build itself. Compiling or running programs other than
openjdk itself on such hardware may still cause unexpected behaviour.

2 files changed, 58 insertions, 2 deletions

diff --git a/lang/openjdk7/hacks.mk b/lang/openjdk7/hacks.mk
index 54d8136ebd0..9520e745b9b 100644
--- a/lang/openjdk7/hacks.mk
+++ b/lang/openjdk7/hacks.mk
@@ -1,4 +1,4 @@
-# $NetBSD: hacks.mk,v 1.1 2012/05/08 09:24:15 abs Exp $
+# $NetBSD: hacks.mk,v 1.2 2015/02/28 14:30:56 tnn Exp $
 
 .if !defined(OPENJDK7_HACKS_MK)
 OPENJDK7_HACKS_MK=	# empty
@@ -12,4 +12,32 @@ post-wrapper:
 	${RM} -f ${BUILDLINK_DIR}/include/jmorecfg.h
 	${RM} -f ${BUILDLINK_DIR}/include/jpeglib.h
 
+# Workaround incorrect constant folding of subnormals in javac when the FPU
+# does not handle subnormal arithmetic, like on ARM in Flush-to-zero mode.
+# These workarounds avoid underflow conditions during the bootstrap so the
+# JDK can correctly build itself. Compiling or running programs other than
+# openjdk itself on such hardware may still cause unexpected behaviour.
+#
+COMPARE_SUBNORMAL_CMD=	${AWK} 'BEGIN {print (1E-307*1E-1==0?"yes":"no");exit;}'
+BROKEN_IEEE_FLOATS:=	${COMPARE_SUBNORMAL_CMD:sh}
+.if !empty(BROKEN_IEEE_FLOATS:Myes)
+PKG_HACKS+=		broken-ieee-floats
+SUBST_CLASSES+=		fpu
+SUBST_STAGE.fpu=	pre-build
+SUBST_MESSAGE.fpu=	Broken FPU detected: applying floating point workarounds
+SUBST_FILES.fpu=	langtools/src/share/classes/com/sun/tools/javac/jvm/Items.java
+SUBST_FILES.fpu+=	langtools/src/share/classes/com/sun/tools/javac/parser/JavacParser.java
+SUBST_FILES.fpu+=	jdk/src/share/classes/sun/misc/DoubleConsts.java
+SUBST_FILES.fpu+=	jdk/src/share/classes/sun/misc/FloatConsts.java
+# {Double,Float}Consts.java: Replace problematic MIN_NORMAL literals with alternative representation
+SUBST_SED.fpu=		-e 's|2.2250738585072014E-308|0x1.0p-1022|g'
+SUBST_SED.fpu+=		-e 's|1.17549435E-38f|0x1.0p-126f|g'
+# JavacParser.java: avoid bogus "fp.number.too.small" error parsing literals representing Double.MIN_VALUE
+SUBST_SED.fpu+=		-e 's|n.floatValue() == 0.0f && !isZero(proper)|& \&\& Float.floatToIntBits(n) != 0x1|'
+SUBST_SED.fpu+=		-e 's|n.doubleValue() == 0.0d && !isZero(proper)|& \&\& Double.doubleToLongBits(n) != 0x1L|'
+# Items.java: Avoid invalid constant folding of literal subnormals to positive zero
+SUBST_SED.fpu+=		-e 's|x == 0.0f && 1.0f / x > 0.0f|Float.floatToIntBits(x) == 0x0|g'
+SUBST_SED.fpu+=		-e 's|x == 0.0d && 1.0d / x > 0.0d|Double.doubleToLongBits(x) == 0x0L|g'
+.endif
+
 .endif
diff --git a/lang/openjdk8/hacks.mk b/lang/openjdk8/hacks.mk
index 7b0c96dc52b..499f503cc25 100644
--- a/lang/openjdk8/hacks.mk
+++ b/lang/openjdk8/hacks.mk
@@ -1,4 +1,4 @@
-# $NetBSD: hacks.mk,v 1.1 2015/02/08 08:41:25 tnn Exp $
+# $NetBSD: hacks.mk,v 1.2 2015/02/28 14:30:56 tnn Exp $
 
 .if !defined(OPENJDK8_HACKS_MK)
 OPENJDK8_HACKS_MK=	# empty
@@ -12,4 +12,32 @@ post-wrapper:
 	${RM} -f ${BUILDLINK_DIR}/include/jmorecfg.h
 	${RM} -f ${BUILDLINK_DIR}/include/jpeglib.h
 
+# Workaround incorrect constant folding of subnormals in javac when the FPU
+# does not handle subnormal arithmetic, like on ARM in Flush-to-zero mode.
+# These workarounds avoid underflow conditions during the bootstrap so the
+# JDK can correctly build itself. Compiling or running programs other than
+# openjdk itself on such hardware may still cause unexpected behaviour.
+#
+COMPARE_SUBNORMAL_CMD=	${AWK} 'BEGIN {print (1E-307*1E-1==0?"yes":"no");exit;}'
+BROKEN_IEEE_FLOATS:=	${COMPARE_SUBNORMAL_CMD:sh}
+.if !empty(BROKEN_IEEE_FLOATS:Myes)
+PKG_HACKS+=		broken-ieee-floats
+SUBST_CLASSES+=		fpu
+SUBST_STAGE.fpu=	pre-build
+SUBST_MESSAGE.fpu=	Broken FPU detected: applying floating point workarounds
+SUBST_FILES.fpu=	langtools/src/share/classes/com/sun/tools/javac/jvm/Items.java
+SUBST_FILES.fpu+=	langtools/src/share/classes/com/sun/tools/javac/parser/JavacParser.java
+SUBST_FILES.fpu+=	jdk/src/share/classes/sun/misc/DoubleConsts.java
+SUBST_FILES.fpu+=	jdk/src/share/classes/sun/misc/FloatConsts.java
+# {Double,Float}Consts.java: Replace problematic MIN_NORMAL literals with alternative representation
+SUBST_SED.fpu=		-e 's|2.2250738585072014E-308|0x1.0p-1022|g'
+SUBST_SED.fpu+=		-e 's|1.17549435E-38f|0x1.0p-126f|g'
+# JavacParser.java: avoid bogus "fp.number.too.small" error parsing literals representing Double.MIN_VALUE
+SUBST_SED.fpu+=		-e 's|n.floatValue() == 0.0f && !isZero(proper)|& \&\& Float.floatToIntBits(n) != 0x1|'
+SUBST_SED.fpu+=		-e 's|n.doubleValue() == 0.0d && !isZero(proper)|& \&\& Double.doubleToLongBits(n) != 0x1L|'
+# Items.java: Avoid invalid constant folding of literal subnormals to positive zero
+SUBST_SED.fpu+=		-e 's|x == 0.0f && 1.0f / x > 0.0f|Float.floatToIntBits(x) == 0x0|g'
+SUBST_SED.fpu+=		-e 's|x == 0.0d && 1.0d / x > 0.0d|Double.doubleToLongBits(x) == 0x0L|g'
+.endif
+
 .endif