From 7e889af76814df67ef912b95ada7ac0b1ebfb7e4 Mon Sep 17 00:00:00 2001 From: Roman Divacky Date: Tue, 7 Jan 2014 20:17:03 +0000 Subject: [PATCH] In the ELFWriter when writing aliased (.set) symbols dont blindly take type from the new symbol but merge them so that the type is never "downgraded". This is probably quite rare, except for IFUNC symbols which we used to misassemble, losing the IFUNC type. Fixes #18372. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198706 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/MC/ELFObjectWriter.cpp | 37 ++++++- test/MC/ELF/type.s | 197 +++++++++++++++++++++++++++++++++++++ 2 files changed, 233 insertions(+), 1 deletion(-) diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp index 6a48d62c8e1..9490a9941ac 100644 --- a/lib/MC/ELFObjectWriter.cpp +++ b/lib/MC/ELFObjectWriter.cpp @@ -532,6 +532,41 @@ void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm, } } +static uint8_t mergeTypeForSet(uint8_t origType, uint8_t newType) { + uint8_t Type = newType; + + // Propagation rules: + // IFUNC > FUNC > OBJECT > NOTYPE + // TLS_OBJECT > OBJECT > NOTYPE + // + // dont let the new type degrade the old type + switch (origType) { + default: + break; + case ELF::STT_GNU_IFUNC: + if (Type == ELF::STT_FUNC || Type == ELF::STT_OBJECT || + Type == ELF::STT_NOTYPE || Type == ELF::STT_TLS) + Type = ELF::STT_GNU_IFUNC; + break; + case ELF::STT_FUNC: + if (Type == ELF::STT_OBJECT || Type == ELF::STT_NOTYPE || + Type == ELF::STT_TLS) + Type = ELF::STT_FUNC; + break; + case ELF::STT_OBJECT: + if (Type == ELF::STT_NOTYPE) + Type = ELF::STT_OBJECT; + break; + case ELF::STT_TLS: + if (Type == ELF::STT_OBJECT || Type == ELF::STT_NOTYPE || + Type == ELF::STT_GNU_IFUNC || Type == ELF::STT_FUNC) + Type = ELF::STT_TLS; + break; + } + + return Type; +} + void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF, MCDataFragment *ShndxF, ELFSymbolData &MSD, @@ -545,7 +580,7 @@ void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF, // Binding and Type share the same byte as upper and lower nibbles uint8_t Binding = MCELF::GetBinding(OrigData); - uint8_t Type = MCELF::GetType(Data); + uint8_t Type = mergeTypeForSet(MCELF::GetType(OrigData), MCELF::GetType(Data)); uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift); // Other and Visibility share the same byte with Visibility using the lower diff --git a/test/MC/ELF/type.s b/test/MC/ELF/type.s index c2f3631ec43..638d8286991 100644 --- a/test/MC/ELF/type.s +++ b/test/MC/ELF/type.s @@ -41,6 +41,95 @@ tls_upper_case: .global tls_upper_case .type tls_upper_case,STT_TLS +// Test that .set doesnt downgrade the type: +// IFUNC > FUNC > OBJECT > NOTYPE +// TLS_OBJECT > OBJECT > NOTYPE +// also TLS_OBJECT is incompatible with IFUNC and FUNC + + .global sym1 + .type sym1, @gnu_indirect_function +alias1: + .global alias1 + .type alias1, @function + .set sym1, alias1 + + .global sym2 + .type sym2, @gnu_indirect_function +alias2: + .global alias2 + .type alias2, @object + .set sym2, alias2 + + .global sym3 + .type sym3, @gnu_indirect_function +alias3: + .global alias3 + .type alias3, @notype + .set sym3, alias3 + + .global sym4 + .type sym4, @function +alias4: + .global alias4 + .type alias4, @object + .set sym4, alias4 + + .global sym5 + .type sym5, @function +alias5: + .global alias5 + .type alias5, @notype + .set sym5, alias5 + + .global sym6 + .type sym6, @object +alias6: + .global alias6 + .type alias6, @notype + .set sym6, alias6 + + .global sym7 + .type sym7, @gnu_indirect_function +alias7: + .global alias7 + .type alias7, @tls_object + .set sym7, alias7 + + .global sym8 + .type sym8, @function + .global alias8 +alias8: + .type alias8, @tls_object + .set sym8, alias8 + + .global sym9 + .type sym9, @tls_object +alias9: + .global alias9 + .type alias9, @object + .set sym9, alias9 + + .global sym10 + .type sym10, @tls_object +alias10: + .global alias10 + .type alias10, @notype + .set sym10, alias10 + + .global sym11 + .type sym11, @tls_object +alias11: + .global alias11 + .type alias11, @gnu_indirect_function + .set sym11, alias11 + + .global sym12 + .type sym12, @tls_object +alias12: + .global alias12 + .type alias12, @function + .set sym12, alias12 + // CHECK: Symbol { // CHECK: Name: bar // CHECK-NEXT: Value: 0x0 @@ -86,6 +175,114 @@ tls_upper_case: // CHECK-NEXT: Other: 0 // CHECK-NEXT: Section: .text (0x1) // CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym1 (54) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: GNU_IFunc (0xA) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym10 (162) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: TLS (0x6) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym11 (176) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: TLS (0x6) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym12 (190) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: TLS (0x6) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym2 (66) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: GNU_IFunc (0xA) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym3 (78) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: GNU_IFunc (0xA) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym4 (90) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: Function (0x2) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym5 (102) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: Function (0x2) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym6 (114) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: Object (0x1) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym7 (126) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: GNU_IFunc (0xA) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym8 (138) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: Function (0x2) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: sym9 (150) +// CHECK-NEXT: Value: 0x0 +// CHECK-NEXT: Size: 0 +// CHECK-NEXT: Binding: Global (0x1) +// CHECK-NEXT: Type: TLS (0x6) +// CHECK-NEXT: Other: 0 +// CHECK-NEXT: Section: .text (0x1) +// CHECK-NEXT: } // CHECK-NEXT: Symbol { // CHECK-NEXT: Name: tls // CHECK-NEXT: Value: 0x0