[llvm] 5ea611d - [BPF] Support weak global variables for BTF
Yonghong Song via llvm-commits
llvm-commits at lists.llvm.org
Sat Dec 7 09:05:12 PST 2019
Author: Yonghong Song
Date: 2019-12-07T08:58:19-08:00
New Revision: 5ea611daf9cb51ba3d6492e50a6b568348fb62c0
URL: https://github.com/llvm/llvm-project/commit/5ea611daf9cb51ba3d6492e50a6b568348fb62c0
DIFF: https://github.com/llvm/llvm-project/commit/5ea611daf9cb51ba3d6492e50a6b568348fb62c0.diff
LOG: [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
Added:
llvm/test/CodeGen/BPF/BTF/weak-global-2.ll
llvm/test/CodeGen/BPF/BTF/weak-global.ll
Modified:
llvm/lib/Target/BPF/BTFDebug.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Target/BPF/BTFDebug.cpp b/llvm/lib/Target/BPF/BTFDebug.cpp
index b2d5fc307ad3..51a6142ece24 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<BTFKindVar>(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 000000000000..a3b187a7d408
--- /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
+
+ at 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 000000000000..79e62f8b9dfe
--- /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
+
+ at 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)
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