tools/syz-declextract: handle ints more carefully

It seems that new clang is more picky about asserts for large ints.
It not assert-fails when converting large ints to int64.
Be more careful when converting these to ints.

5 files changed, 37 insertions, 2 deletions

diff --git a/tools/syz-declextract/clangtool/declextract.cpp b/tools/syz-declextract/clangtool/declextract.cpp
index 786f66ca5..2df651e07 100644
--- a/tools/syz-declextract/clangtool/declextract.cpp
+++ b/tools/syz-declextract/clangtool/declextract.cpp
@@ -494,7 +494,13 @@ int Extractor::alignofType(const Type* T) { return static_cast<int>(Context->get
 template <typename T> T Extractor::evaluate(const Expr* E) {
   Expr::EvalResult Res;
   E->EvaluateAsConstantExpr(Res, *Context);
-  return static_cast<T>(Res.Val.getInt().getExtValue());
+  // TODO: it's unclear what to do if it's not Int (in some cases we see None here).
+  if (Res.Val.getKind() != APValue::Int)
+    return 0;
+  auto val = Res.Val.getInt();
+  if (val.isSigned())
+    return val.sextOrTrunc(64).getSExtValue();
+  return val.zextOrTrunc(64).getZExtValue();
 }
 
 void Extractor::matchNetlinkPolicy() {
diff --git a/tools/syz-declextract/testdata/scopes.c b/tools/syz-declextract/testdata/scopes.c
index d53ca391d..57809ae3d 100644
--- a/tools/syz-declextract/testdata/scopes.c
+++ b/tools/syz-declextract/testdata/scopes.c
@@ -5,6 +5,9 @@
 #include "include/syscall.h"
 #include "include/uapi/file_operations.h"
 
+#define LARGE_UINT (1ull<<63) // this is supposed to overflow int64
+#define LARGE_SINT (20ll<<63) // this is supposed to overflow uint64
+
 static int scopes_helper(long cmd, long aux) {
 	switch (cmd) {
 	case FOO_IOCTL7:
@@ -12,6 +15,9 @@ static int scopes_helper(long cmd, long aux) {
 	case FOO_IOCTL8:
 		__fget_light(aux);
 		break;
+	case LARGE_UINT:
+	case LARGE_SINT:
+		break;
 	}
 	return 0;
 }
diff --git a/tools/syz-declextract/testdata/scopes.c.info b/tools/syz-declextract/testdata/scopes.c.info
index 8f18c7352..aeee09ace 100644
--- a/tools/syz-declextract/testdata/scopes.c.info
+++ b/tools/syz-declextract/testdata/scopes.c.info
@@ -1 +1 @@
-SYSCALL	scopes0	func:__do_sys_scopes0	loc:32	access:unknown	manual_desc:false	auto_desc:true	file:scopes.c	subsystem:kernel
+SYSCALL	scopes0	func:__do_sys_scopes0	loc:35	access:unknown	manual_desc:false	auto_desc:true	file:scopes.c	subsystem:kernel
diff --git a/tools/syz-declextract/testdata/scopes.c.json b/tools/syz-declextract/testdata/scopes.c.json
index ab03673b0..b5921869c 100644
--- a/tools/syz-declextract/testdata/scopes.c.json
+++ b/tools/syz-declextract/testdata/scopes.c.json
@@ -284,6 +284,14 @@
 							}
 						}
 					]
+				},
+				{
+					"arg": 0,
+					"values": [
+						"LARGE_UINT",
+						"LARGE_SINT"
+					],
+					"loc": 3
 				}
 			]
 		}
@@ -318,6 +326,16 @@
 			"name": "FOO_IOCTL8",
 			"filename": "include/uapi/file_operations.h",
 			"value": 25352
+		},
+		{
+			"name": "LARGE_SINT",
+			"filename": "scopes.c",
+			"value": 0
+		},
+		{
+			"name": "LARGE_UINT",
+			"filename": "scopes.c",
+			"value": -9223372036854775808
 		}
 	],
 	"structs": [
diff --git a/tools/syz-declextract/testdata/scopes.c.txt b/tools/syz-declextract/testdata/scopes.c.txt
index fa923fc31..862b01cfd 100644
--- a/tools/syz-declextract/testdata/scopes.c.txt
+++ b/tools/syz-declextract/testdata/scopes.c.txt
@@ -18,3 +18,8 @@ scopes0$auto_FOO_IOCTL3(x int32, cmd const[FOO_IOCTL3], aux fd) fd
 scopes0$auto_FOO_IOCTL4(x int32, cmd const[FOO_IOCTL4], aux fd)
 scopes0$auto_FOO_IOCTL7(x int32, cmd const[FOO_IOCTL7], aux fd) fd
 scopes0$auto_FOO_IOCTL8(x fd, cmd const[FOO_IOCTL8], aux fd)
+scopes0$auto_LARGE_SINT(x int32, cmd const[LARGE_SINT], aux fd)
+scopes0$auto_LARGE_UINT(x int32, cmd const[LARGE_UINT], aux fd)
+
+define LARGE_SINT	0
+define LARGE_UINT	-9223372036854775808