mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2025-02-01 05:01:59 +01:00
BPF: generate BTF info for LD_imm64 loaded function pointer
For an example like below,
extern int do_work(int);
long bpf_helper(void *callback_fn);
long prog() {
return bpf_helper(&do_work);
}
The final generated codes look like:
r1 = do_work ll
call bpf_helper
exit
where we have debuginfo for do_work() extern function:
!17 = !DISubprogram(name: "do_work", ...)
This patch implemented to add additional checking
in processing LD_imm64 operands for possible function pointers
so BTF for bpf function do_work() can be properly generated.
The original llvm function name processReloc() is renamed to
processGlobalValue() to better reflect what the function is doing.
Differential Revision: https://reviews.llvm.org/D100568
This commit is contained in:
Yonghong Song
parent
1f40f70a19
commit
1c5a0c4acc
@ -1030,13 +1030,16 @@ void BTFDebug::generatePatchImmReloc(const MCSymbol *ORSym, uint32_t RootId,
|
||||
FieldRelocTable[SecNameOff].push_back(FieldReloc);
|
||||
}
|
||||
|
||||
void BTFDebug::processReloc(const MachineOperand &MO) {
|
||||
void BTFDebug::processGlobalValue(const MachineOperand &MO) {
|
||||
// check whether this is a candidate or not
|
||||
if (MO.isGlobal()) {
|
||||
const GlobalValue *GVal = MO.getGlobal();
|
||||
auto *GVar = dyn_cast<GlobalVariable>(GVal);
|
||||
if (!GVar)
|
||||
if (!GVar) {
|
||||
// Not a global variable. Maybe an extern function reference.
|
||||
processFuncPrototypes(dyn_cast<Function>(GVal));
|
||||
return;
|
||||
}
|
||||
|
||||
if (!GVar->hasAttribute(BPFCoreSharedInfo::AmaAttr) &&
|
||||
!GVar->hasAttribute(BPFCoreSharedInfo::TypeIdAttr))
|
||||
@ -1087,12 +1090,12 @@ void BTFDebug::beginInstruction(const MachineInstr *MI) {
|
||||
//
|
||||
// If the insn is "r2 = LD_imm64 @<an TypeIdAttr global>",
|
||||
// The LD_imm64 result will be replaced with a btf type id.
|
||||
processReloc(MI->getOperand(1));
|
||||
processGlobalValue(MI->getOperand(1));
|
||||
} else if (MI->getOpcode() == BPF::CORE_MEM ||
|
||||
MI->getOpcode() == BPF::CORE_ALU32_MEM ||
|
||||
MI->getOpcode() == BPF::CORE_SHIFT) {
|
||||
// relocation insn is a load, store or shift insn.
|
||||
processReloc(MI->getOperand(3));
|
||||
processGlobalValue(MI->getOperand(3));
|
||||
} else if (MI->getOpcode() == BPF::JAL) {
|
||||
// check extern function references
|
||||
const MachineOperand &MO = MI->getOperand(0);
|
||||
|
||||
@ -320,8 +320,9 @@ class BTFDebug : public DebugHandlerBase {
|
||||
/// Populating unprocessed type on demand.
|
||||
unsigned populateType(const DIType *Ty);
|
||||
|
||||
/// Process relocation instructions.
|
||||
void processReloc(const MachineOperand &MO);
|
||||
/// Process global variables referenced by relocation instructions
|
||||
/// and extern function references.
|
||||
void processGlobalValue(const MachineOperand &MO);
|
||||
|
||||
/// Emit common header of .BTF and .BTF.ext sections.
|
||||
void emitCommonHeader();
|
||||
|
||||
76
test/CodeGen/BPF/BTF/extern-func-ptr.ll
Normal file
76
test/CodeGen/BPF/BTF/extern-func-ptr.ll
Normal file
@ -0,0 +1,76 @@
|
||||
; RUN: llc -march=bpfel -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
|
||||
; RUN: llc -march=bpfeb -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
|
||||
;
|
||||
; Source code:
|
||||
; extern int do_work(int) __attribute__((section(".callback_fn")));
|
||||
; long bpf_helper(void *callback_fn);
|
||||
; long prog() {
|
||||
; return bpf_helper(&do_work);
|
||||
; }
|
||||
; Compilation flag:
|
||||
; clang -target bpf -O2 -g -S -emit-llvm test.c
|
||||
|
||||
; Function Attrs: nounwind
|
||||
define dso_local i64 @prog() local_unnamed_addr #0 !dbg !7 {
|
||||
entry:
|
||||
%call = tail call i64 @bpf_helper(i8* bitcast (i32 (i32)* @do_work to i8*)) #2, !dbg !11
|
||||
ret i64 %call, !dbg !12
|
||||
}
|
||||
|
||||
; CHECK: .long 0 # BTF_KIND_FUNC_PROTO(id = 4)
|
||||
; CHECK-NEXT: .long 218103809 # 0xd000001
|
||||
; CHECK-NEXT: .long 5
|
||||
; CHECK-NEXT: .long 0
|
||||
; CHECK-NEXT: .long 5
|
||||
; CHECK-NEXT: .long 51 # BTF_KIND_INT(id = 5)
|
||||
; CHECK-NEXT: .long 16777216 # 0x1000000
|
||||
; CHECK-NEXT: .long 4
|
||||
; CHECK-NEXT: .long 16777248 # 0x1000020
|
||||
; CHECK-NEXT: .long 55 # BTF_KIND_FUNC(id = 6)
|
||||
; CHECK-NEXT: .long 201326594 # 0xc000002
|
||||
; CHECK-NEXT: .long 4
|
||||
|
||||
; CHECK: .long 74 # BTF_KIND_DATASEC(id = 10)
|
||||
; CHECK-NEXT: .long 251658241 # 0xf000001
|
||||
; CHECK-NEXT: .long 0
|
||||
; CHECK-NEXT: .long 6
|
||||
; CHECK-NEXT: .long do_work
|
||||
; CHECK-NEXT: .long 0
|
||||
|
||||
; CHECK: .ascii "int" # string offset=51
|
||||
; CHECK: .ascii "do_work" # string offset=55
|
||||
; CHECK: .ascii ".callback_fn" # string offset=74
|
||||
|
||||
declare !dbg !13 dso_local i64 @bpf_helper(i8*) local_unnamed_addr #1
|
||||
|
||||
declare !dbg !17 dso_local i32 @do_work(i32) #1 section ".callback_fn"
|
||||
|
||||
attributes #0 = { nounwind "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
|
||||
attributes #1 = { "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
|
||||
attributes #2 = { nounwind }
|
||||
|
||||
!llvm.dbg.cu = !{!0}
|
||||
!llvm.module.flags = !{!3, !4, !5}
|
||||
!llvm.ident = !{!6}
|
||||
|
||||
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 13.0.0 (https://github.com/llvm/llvm-project.git aa382ed8a38d5efa118e1b2617544f5c253658a9)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
|
||||
!1 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/btf/core")
|
||||
!2 = !{}
|
||||
!3 = !{i32 7, !"Dwarf Version", i32 4}
|
||||
!4 = !{i32 2, !"Debug Info Version", i32 3}
|
||||
!5 = !{i32 1, !"wchar_size", i32 4}
|
||||
!6 = !{!"clang version 13.0.0 (https://github.com/llvm/llvm-project.git aa382ed8a38d5efa118e1b2617544f5c253658a9)"}
|
||||
!7 = distinct !DISubprogram(name: "prog", scope: !1, file: !1, line: 3, type: !8, scopeLine: 3, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
|
||||
!8 = !DISubroutineType(types: !9)
|
||||
!9 = !{!10}
|
||||
!10 = !DIBasicType(name: "long int", size: 64, encoding: DW_ATE_signed)
|
||||
!11 = !DILocation(line: 4, column: 12, scope: !7)
|
||||
!12 = !DILocation(line: 4, column: 5, scope: !7)
|
||||
!13 = !DISubprogram(name: "bpf_helper", scope: !1, file: !1, line: 2, type: !14, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
|
||||
!14 = !DISubroutineType(types: !15)
|
||||
!15 = !{!10, !16}
|
||||
!16 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
|
||||
!17 = !DISubprogram(name: "do_work", scope: !1, file: !1, line: 1, type: !18, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
|
||||
!18 = !DISubroutineType(types: !19)
|
||||
!19 = !{!20, !20}
|
||||
!20 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
|
||||
Loading…
x
Reference in New Issue
Block a user