From 5ea611daf9cb51ba3d6492e50a6b568348fb62c0 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Fri, 6 Dec 2019 23:00:41 -0800 Subject: [PATCH] [BPF] Support weak global variables for BTF Generate types for global variables with "weak" attribute. Keep allocation scope the same for both weak and non-weak globals as ELF symbol table can determine whether a global symbol is weak or not. Differential Revision: https://reviews.llvm.org/D71162 --- llvm/lib/Target/BPF/BTFDebug.cpp | 11 ++--- llvm/test/CodeGen/BPF/BTF/weak-global-2.ll | 66 ++++++++++++++++++++++++++++++ llvm/test/CodeGen/BPF/BTF/weak-global.ll | 65 +++++++++++++++++++++++++++++ 3 files changed, 137 insertions(+), 5 deletions(-) create mode 100644 llvm/test/CodeGen/BPF/BTF/weak-global-2.ll create mode 100644 llvm/test/CodeGen/BPF/BTF/weak-global.ll diff --git a/llvm/lib/Target/BPF/BTFDebug.cpp b/llvm/lib/Target/BPF/BTFDebug.cpp index b2d5fc3..51a6142 100644 --- a/llvm/lib/Target/BPF/BTFDebug.cpp +++ b/llvm/lib/Target/BPF/BTFDebug.cpp @@ -1092,7 +1092,7 @@ void BTFDebug::processGlobals(bool ProcessingMapDef) { // Only support the following globals: // . static variables - // . non-static global variables + // . non-static weak or non-weak global variables // Essentially means: // . .bcc/.data/.rodata DataSec entities only contain static data // . Other DataSec entities contain static or initialized global data. @@ -1101,12 +1101,13 @@ void BTFDebug::processGlobals(bool ProcessingMapDef) { // corresponding ELF section flags. auto Linkage = Global.getLinkage(); if (Linkage != GlobalValue::InternalLinkage && - Linkage != GlobalValue::ExternalLinkage) + Linkage != GlobalValue::ExternalLinkage && + Linkage != GlobalValue::WeakAnyLinkage) continue; - uint32_t GVarInfo = Linkage == GlobalValue::ExternalLinkage - ? BTF::VAR_GLOBAL_ALLOCATED - : BTF::VAR_STATIC; + uint32_t GVarInfo = Linkage == GlobalValue::InternalLinkage + ? BTF::VAR_STATIC + : BTF::VAR_GLOBAL_ALLOCATED; auto VarEntry = std::make_unique(Global.getName(), GVTypeId, GVarInfo); uint32_t VarId = addType(std::move(VarEntry)); diff --git a/llvm/test/CodeGen/BPF/BTF/weak-global-2.ll b/llvm/test/CodeGen/BPF/BTF/weak-global-2.ll new file mode 100644 index 0000000..a3b187a --- /dev/null +++ b/llvm/test/CodeGen/BPF/BTF/weak-global-2.ll @@ -0,0 +1,66 @@ +; 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: +; char g __attribute__((weak)) = 2; +; int test() { +; return g; +; } +; Compilation flag: +; clang -target bpf -O2 -g -S -emit-llvm test.c + +@g = weak dso_local local_unnamed_addr global i8 2, align 1, !dbg !0 +; Function Attrs: norecurse nounwind readonly +define dso_local i32 @test() local_unnamed_addr #0 !dbg !11 { +entry: + %0 = load i8, i8* @g, align 1, !dbg !15, !tbaa !16 + %conv = sext i8 %0 to i32, !dbg !15 + ret i32 %conv, !dbg !19 +} + +; CHECK: .long 55 # BTF_KIND_INT(id = 4) +; CHECK-NEXT: .long 16777216 # 0x1000000 +; CHECK-NEXT: .long 1 +; CHECK-NEXT: .long 16777224 # 0x1000008 +; CHECK-NEXT: .long 60 # BTF_KIND_VAR(id = 5) +; CHECK-NEXT: .long 234881024 # 0xe000000 +; CHECK-NEXT: .long 4 +; CHECK-NEXT: .long 1 +; CHECK-NEXT: .long 62 # BTF_KIND_DATASEC(id = 6) +; CHECK-NEXT: .long 251658241 # 0xf000001 +; CHECK-NEXT: .long 0 +; CHECK-NEXT: .long 5 +; CHECK-NEXT: .long g +; CHECK-NEXT: .long 1 + +; CHECK: .ascii "char" # string offset=55 +; CHECK: .byte 103 # string offset=60 +; CHECK: .ascii ".data" # string offset=62 + + +attributes #0 = { norecurse nounwind readonly "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" } + +!llvm.dbg.cu = !{!2} +!llvm.module.flags = !{!7, !8, !9} +!llvm.ident = !{!10} + +!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression()) +!1 = distinct !DIGlobalVariable(name: "g", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true) +!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 10.0.0 (https://github.com/llvm/llvm-project.git edf6717d8d30034da932b95350898e03c90a5082)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None) +!3 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/work/tests/global") +!4 = !{} +!5 = !{!0} +!6 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char) +!7 = !{i32 7, !"Dwarf Version", i32 4} +!8 = !{i32 2, !"Debug Info Version", i32 3} +!9 = !{i32 1, !"wchar_size", i32 4} +!10 = !{!"clang version 10.0.0 (https://github.com/llvm/llvm-project.git edf6717d8d30034da932b95350898e03c90a5082)"} +!11 = distinct !DISubprogram(name: "test", scope: !3, file: !3, line: 2, type: !12, scopeLine: 2, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !4) +!12 = !DISubroutineType(types: !13) +!13 = !{!14} +!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!15 = !DILocation(line: 3, column: 10, scope: !11) +!16 = !{!17, !17, i64 0} +!17 = !{!"omnipotent char", !18, i64 0} +!18 = !{!"Simple C/C++ TBAA"} +!19 = !DILocation(line: 3, column: 3, scope: !11) diff --git a/llvm/test/CodeGen/BPF/BTF/weak-global.ll b/llvm/test/CodeGen/BPF/BTF/weak-global.ll new file mode 100644 index 0000000..79e62f8 --- /dev/null +++ b/llvm/test/CodeGen/BPF/BTF/weak-global.ll @@ -0,0 +1,65 @@ +; 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: +; char g __attribute__((weak)); +; int test() { +; return g; +; } +; Compilation flag: +; clang -target bpf -O2 -g -S -emit-llvm test.c + +@g = weak dso_local local_unnamed_addr global i8 0, align 1, !dbg !0 +; Function Attrs: norecurse nounwind readonly +define dso_local i32 @test() local_unnamed_addr #0 !dbg !11 { +entry: + %0 = load i8, i8* @g, align 1, !dbg !15, !tbaa !16 + %conv = sext i8 %0 to i32, !dbg !15 + ret i32 %conv, !dbg !19 +} + +; CHECK: .long 55 # BTF_KIND_INT(id = 4) +; CHECK-NEXT: .long 16777216 # 0x1000000 +; CHECK-NEXT: .long 1 +; CHECK-NEXT: .long 16777224 # 0x1000008 +; CHECK-NEXT: .long 60 # BTF_KIND_VAR(id = 5) +; CHECK-NEXT: .long 234881024 # 0xe000000 +; CHECK-NEXT: .long 4 +; CHECK-NEXT: .long 1 +; CHECK-NEXT: .long 62 # BTF_KIND_DATASEC(id = 6) +; CHECK-NEXT: .long 251658241 # 0xf000001 +; CHECK-NEXT: .long 0 +; CHECK-NEXT: .long 5 +; CHECK-NEXT: .long g +; CHECK-NEXT: .long 1 + +; CHECK: .ascii "char" # string offset=55 +; CHECK: .byte 103 # string offset=60 +; CHECK: .ascii ".bss" # string offset=62 + +attributes #0 = { norecurse nounwind readonly "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" } + +!llvm.dbg.cu = !{!2} +!llvm.module.flags = !{!7, !8, !9} +!llvm.ident = !{!10} + +!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression()) +!1 = distinct !DIGlobalVariable(name: "g", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true) +!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 10.0.0 (https://github.com/llvm/llvm-project.git edf6717d8d30034da932b95350898e03c90a5082)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None) +!3 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/work/tests/global") +!4 = !{} +!5 = !{!0} +!6 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char) +!7 = !{i32 7, !"Dwarf Version", i32 4} +!8 = !{i32 2, !"Debug Info Version", i32 3} +!9 = !{i32 1, !"wchar_size", i32 4} +!10 = !{!"clang version 10.0.0 (https://github.com/llvm/llvm-project.git edf6717d8d30034da932b95350898e03c90a5082)"} +!11 = distinct !DISubprogram(name: "test", scope: !3, file: !3, line: 2, type: !12, scopeLine: 2, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !4) +!12 = !DISubroutineType(types: !13) +!13 = !{!14} +!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!15 = !DILocation(line: 3, column: 10, scope: !11) +!16 = !{!17, !17, i64 0} +!17 = !{!"omnipotent char", !18, i64 0} +!18 = !{!"Simple C/C++ TBAA"} +!19 = !DILocation(line: 3, column: 3, scope: !11) -- 2.7.4