OSchip
/
llvm-project
mirror of https://github.com/THU-DSP-LAB/llvm-project.git
13
0
Fork 2
Code Issues Packages Projects Releases Wiki Activity

BPF: fix enum value 0 issue for __builtin_preserve_enum_value() 

Lorenz Bauer reported that the following code will have
compilation error for bpf target:
    enum e { TWO };
    bpf_core_enum_value_exists(enum e, TWO);
The clang emitted the following error message:
    __builtin_preserve_enum_value argument 1 invalid

In SemaChecking, an expression like "*(enum NAME)1" will have
cast kind CK_IntegralToPointer, but "*(enum NAME)0" will have
cast kind CK_NullToPointer. Current implementation only permits
CK_IntegralToPointer, missing enum value 0 case.

This patch permits CK_NullToPointer cast kind and
the above test case can pass now.

Differential Revision: https://reviews.llvm.org/D97659
This commit is contained in:
Yonghong Song 2021-02-28 22:46:39 -08:00
parent 52b8e10597
commit 283db5f083
2 changed files with 15 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
clang/lib/Sema/SemaChecking.cpp
View File

@ -2626,7 +2626,10 @@ static bool isValidBPFPreserveEnumValueArg(Expr *Arg) {
return false;
const auto *CE = dyn_cast<CStyleCastExpr>(UO->getSubExpr());
if (!CE || CE->getCastKind() != CK_IntegralToPointer)
if (!CE)
return false;
if (CE->getCastKind() != CK_IntegralToPointer &&
CE->getCastKind() != CK_NullToPointer)
return false;
// The integer must be from an EnumConstantDecl.

12
clang/test/CodeGen/builtins-bpf-preserve-field-info-4.c
View File

@ -4,10 +4,11 @@
#define _(x, y) (__builtin_preserve_enum_value((x), (y)))
enum AA {
VAL0 = 0,
VAL1 = 2,
VAL2 = 0xffffffff80000000UL,
};
typedef enum { VAL10 = -2, VAL11 = 0xffff8000, } __BB;
typedef enum { VAL00, VAL10 = -2, VAL11 = 0xffff8000, } __BB;
unsigned unit1() {
return _(*(enum AA *)VAL1, 0) + _(*(__BB *)VAL10, 1);
@ -17,10 +18,16 @@ unsigned unit2() {
return _(*(enum AA *)VAL2, 0) + _(*(__BB *)VAL11, 1);
}
unsigned unit3() {
return _(*(enum AA *)VAL0, 0) + _(*(__BB *)VAL00, 1);
}
// CHECK: @0 = private unnamed_addr constant [7 x i8] c"VAL1:2\00", align 1
// CHECK: @1 = private unnamed_addr constant [9 x i8] c"VAL10:-2\00", align 1
// CHECK: @2 = private unnamed_addr constant [17 x i8] c"VAL2:-2147483648\00", align 1
// CHECK: @3 = private unnamed_addr constant [17 x i8] c"VAL11:4294934528\00", align 1
// CHECK: @4 = private unnamed_addr constant [7 x i8] c"VAL0:0\00", align 1
// CHECK: @5 = private unnamed_addr constant [8 x i8] c"VAL00:0\00", align 1
// CHECK: call i64 @llvm.bpf.preserve.enum.value(i32 0, i8* getelementptr inbounds ([7 x i8], [7 x i8]* @0, i32 0, i32 0), i64 0), !dbg !{{[0-9]+}}, !llvm.preserve.access.index ![[ENUM_AA:[0-9]+]]
// CHECK: call i64 @llvm.bpf.preserve.enum.value(i32 1, i8* getelementptr inbounds ([9 x i8], [9 x i8]* @1, i32 0, i32 0), i64 1), !dbg !{{[0-9]+}}, !llvm.preserve.access.index ![[TYPEDEF_ENUM:[0-9]+]]
@ -28,5 +35,8 @@ unsigned unit2() {
// CHECK: call i64 @llvm.bpf.preserve.enum.value(i32 2, i8* getelementptr inbounds ([17 x i8], [17 x i8]* @2, i32 0, i32 0), i64 0), !dbg !{{[0-9]+}}, !llvm.preserve.access.index ![[ENUM_AA]]
// CHECK: call i64 @llvm.bpf.preserve.enum.value(i32 3, i8* getelementptr inbounds ([17 x i8], [17 x i8]* @3, i32 0, i32 0), i64 1), !dbg !{{[0-9]+}}, !llvm.preserve.access.index ![[TYPEDEF_ENUM]]
// CHECK: call i64 @llvm.bpf.preserve.enum.value(i32 4, i8* getelementptr inbounds ([7 x i8], [7 x i8]* @4, i32 0, i32 0), i64 0), !dbg !{{[0-9]+}}, !llvm.preserve.access.index ![[ENUM_AA]]
// CHECK: call i64 @llvm.bpf.preserve.enum.value(i32 5, i8* getelementptr inbounds ([8 x i8], [8 x i8]* @5, i32 0, i32 0), i64 1), !dbg !{{[0-9]+}}, !llvm.preserve.access.index ![[TYPEDEF_ENUM]]
// CHECK: ![[ENUM_AA]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "AA"
// CHECK: ![[TYPEDEF_ENUM]] = !DIDerivedType(tag: DW_TAG_typedef, name: "__BB"