Reviewers: Sven Panne,
Description:
[turbofan] Use appropriate type for NodeId.
Up until now we used int32_t for NodeId, but that was not ideal because
negative values are invalid for NodeId and we use it as an array index
for example in the NodeMarker class, where C++ compilers on x64 have to
generate code that does proper sign extension for the indices, which is
completely unnecessary.
[email protected]
Please review this at https://codereview.chromium.org/1178403004/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+38, -4 lines):
M include/v8config.h
M src/base/bits.h
M src/compiler/graph.h
M src/compiler/graph.cc
M src/compiler/graph-reducer.h
M src/compiler/node.h
M test/unittests/base/bits-unittest.cc
Index: include/v8config.h
diff --git a/include/v8config.h b/include/v8config.h
index
a8b54c18d83c83b6ccb7702d570799dabdd9b7f0..24b0e5ff3ef64d7ff11f30d495ff7953c0bc4f61
100644
--- a/include/v8config.h
+++ b/include/v8config.h
@@ -183,6 +183,7 @@
// V8_HAS_BUILTIN_POPCOUNT - __builtin_popcount() supported
// V8_HAS_BUILTIN_SADD_OVERFLOW - __builtin_sadd_overflow()
supported
// V8_HAS_BUILTIN_SSUB_OVERFLOW - __builtin_ssub_overflow()
supported
+// V8_HAS_BUILTIN_UADD_OVERFLOW - __builtin_uadd_overflow()
supported
// V8_HAS_DECLSPEC_ALIGN - __declspec(align(n)) supported
// V8_HAS_DECLSPEC_DEPRECATED - __declspec(deprecated) supported
// V8_HAS_DECLSPEC_NOINLINE - __declspec(noinline) supported
@@ -221,6 +222,7 @@
# define V8_HAS_BUILTIN_POPCOUNT (__has_builtin(__builtin_popcount))
# define V8_HAS_BUILTIN_SADD_OVERFLOW
(__has_builtin(__builtin_sadd_overflow))
# define V8_HAS_BUILTIN_SSUB_OVERFLOW
(__has_builtin(__builtin_ssub_overflow))
+# define V8_HAS_BUILTIN_UADD_OVERFLOW
(__has_builtin(__builtin_uadd_overflow))
# define V8_HAS_CXX11_ALIGNAS (__has_feature(cxx_alignas))
# define V8_HAS_CXX11_STATIC_ASSERT (__has_feature(cxx_static_assert))
Index: src/base/bits.h
diff --git a/src/base/bits.h b/src/base/bits.h
index
b237d62bcb1d6f47500a42ffe76bef510e2006d6..abcfd9a9eddce4a45671712d7abbb5da6f0d5fbf
100644
--- a/src/base/bits.h
+++ b/src/base/bits.h
@@ -236,6 +236,19 @@ int32_t SignedDiv32(int32_t lhs, int32_t rhs);
int32_t SignedMod32(int32_t lhs, int32_t rhs);
+// UnsignedAddOverflow32(lhs,rhs,val) performs an unsigned summation of |
lhs|
+// and |rhs| and stores the result into the variable pointed to by |val|
and
+// returns true if the unsigned summation resulted in an overflow.
+inline bool UnsignedAddOverflow32(uint32_t lhs, uint32_t rhs, uint32_t*
val) {
+#if V8_HAS_BUILTIN_SADD_OVERFLOW
+ return __builtin_uadd_overflow(lhs, rhs, val);
+#else
+ *val = lhs + rhs;
+ return *val < (lhs | rhs);
+#endif
+}
+
+
// UnsignedDiv32(lhs, rhs) divides |lhs| by |rhs| and returns the quotient
// truncated to uint32. If |rhs| is zero, then zero is returned.
inline uint32_t UnsignedDiv32(uint32_t lhs, uint32_t rhs) {
Index: src/compiler/graph-reducer.h
diff --git a/src/compiler/graph-reducer.h b/src/compiler/graph-reducer.h
index
21e0a84b99c86021556848e316a66f7c0e6d15c9..a8a907fa12731b29b0834d9fa207a565d371e6b2
100644
--- a/src/compiler/graph-reducer.h
+++ b/src/compiler/graph-reducer.h
@@ -19,7 +19,7 @@ class Node;
// NodeIds are identifying numbers for nodes that can be used to index
auxiliary
// out-of-line data associated with each node.
-typedef int32_t NodeId;
+typedef uint32_t NodeId;
// Represents the result of trying to reduce a node in the graph.
Index: src/compiler/graph.cc
diff --git a/src/compiler/graph.cc b/src/compiler/graph.cc
index
193861187ba1f8aeec349c6787a7c4e133f55a5b..07bf2ba44eb7cdb068796d0ed179f628172c444c
100644
--- a/src/compiler/graph.cc
+++ b/src/compiler/graph.cc
@@ -53,7 +53,7 @@ Node* Graph::NewNode(const Operator* op, int input_count,
Node** inputs,
NodeId Graph::NextNodeId() {
NodeId const id = next_node_id_;
- CHECK(!base::bits::SignedAddOverflow32(id, 1, &next_node_id_));
+ CHECK(!base::bits::UnsignedAddOverflow32(id, 1, &next_node_id_));
return id;
}
Index: src/compiler/graph.h
diff --git a/src/compiler/graph.h b/src/compiler/graph.h
index
0b1277ca1dcb1ff0d16d3edafc40bffffc214d28..6b4c8a1bce18648e9674a9ebc9db0f8f9dd9c98e
100644
--- a/src/compiler/graph.h
+++ b/src/compiler/graph.h
@@ -26,7 +26,7 @@ typedef uint32_t Mark;
// NodeIds are identifying numbers for nodes that can be used to index
auxiliary
// out-of-line data associated with each node.
-typedef int32_t NodeId;
+typedef uint32_t NodeId;
class Graph : public ZoneObject {
Index: src/compiler/node.h
diff --git a/src/compiler/node.h b/src/compiler/node.h
index
16b2aeeb1cc2b12e982ace299453f63645c5e8f7..08b775c1fff688376140e1316c236b141eca09b8
100644
--- a/src/compiler/node.h
+++ b/src/compiler/node.h
@@ -27,7 +27,7 @@ typedef uint32_t Mark;
// NodeIds are identifying numbers for nodes that can be used to index
auxiliary
// out-of-line data associated with each node.
-typedef int32_t NodeId;
+typedef uint32_t NodeId;
// A Node is the basic primitive of graphs. Nodes are chained together by
Index: test/unittests/base/bits-unittest.cc
diff --git a/test/unittests/base/bits-unittest.cc
b/test/unittests/base/bits-unittest.cc
index
9caba8484eee0de05833a2aff1d4edcadc777435..3d17a050dbdef9dcb1618a564ad335c8227c0a24
100644
--- a/test/unittests/base/bits-unittest.cc
+++ b/test/unittests/base/bits-unittest.cc
@@ -255,6 +255,25 @@ TEST(Bits, SignedMod32) {
}
+TEST(Bits, UnsignedAddOverflow32) {
+ uint32_t val = 0;
+ EXPECT_FALSE(UnsignedAddOverflow32(0, 0, &val));
+ EXPECT_EQ(0u, val);
+ EXPECT_TRUE(
+ UnsignedAddOverflow32(std::numeric_limits<uint32_t>::max(), 1u,
&val));
+ EXPECT_EQ(std::numeric_limits<uint32_t>::min(), val);
+ EXPECT_TRUE(UnsignedAddOverflow32(std::numeric_limits<uint32_t>::max(),
+ std::numeric_limits<uint32_t>::max(),
+ &val));
+ TRACED_FORRANGE(uint32_t, i, 1, 50) {
+ TRACED_FORRANGE(uint32_t, j, 1, i) {
+ EXPECT_FALSE(UnsignedAddOverflow32(i, j, &val));
+ EXPECT_EQ(i + j, val);
+ }
+ }
+}
+
+
TEST(Bits, UnsignedDiv32) {
TRACED_FORRANGE(uint32_t, i, 0, 50) {
EXPECT_EQ(0u, UnsignedDiv32(i, 0));
--
--
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