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Use upstream $local symbol instead of $eh_alias #750

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merged 5 commits into from
Sep 17, 2024
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Use upstream $local symbol instead of $eh_alias #750

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46c4d31
[CHERI-RISC-V] Baseline test for function entry directives
arichardson Sep 10, 2024
18a3140
[CHERI-Generic] Update landingpad tests to use opaque pointers
arichardson Sep 10, 2024
c9efae8
[CHERI] Emit $eh_alias label .type directive in correct location
arichardson Sep 10, 2024
d2e741e
[CHERI] Reuse the $local function symbol for landing pads
arichardson Sep 11, 2024
1355df3
[ELF][CHERI] Rewrite exception-table test in LLVM IR
arichardson Sep 11, 2024
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104 changes: 0 additions & 104 deletions lld/test/ELF/cheri/exception-table.cpp
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215 changes: 215 additions & 0 deletions lld/test/ELF/cheri/exception-table.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,215 @@
; RUN: %cheri_purecap_llc --relocation-model=pic < %s -filetype=obj -o %t.o
; RUN: llvm-readobj -r %t.o | FileCheck %s --check-prefix=MIPS-OBJ-RELOCS
; RUN: %riscv64_cheri_purecap_llc --relocation-model=pic < %s -filetype=obj -o %t-riscv64.o
; RUN: llvm-readobj -r %t-riscv64.o | FileCheck %s --check-prefix=RV64-OBJ-RELOCS
;; Should have two relocations against a local alias for _Z4testll
; MIPS-OBJ-RELOCS: Section ({{.+}}) .rela.gcc_except_table {
; MIPS-OBJ-RELOCS-NEXT: R_MIPS_CHERI_CAPABILITY/R_MIPS_NONE/R_MIPS_NONE .L_Z4testll$local 0x80
; MIPS-OBJ-RELOCS-NEXT: R_MIPS_CHERI_CAPABILITY/R_MIPS_NONE/R_MIPS_NONE .L_Z4testll$local 0x60
; MIPS-OBJ-RELOCS-NEXT: R_MIPS_CHERI_CAPABILITY/R_MIPS_NONE/R_MIPS_NONE .L_Z5test2ll$local 0x60
; MIPS-OBJ-RELOCS-NEXT: R_MIPS_PC32/R_MIPS_NONE/R_MIPS_NONE .L_ZTIl.DW.stub 0x0
; MIPS-OBJ-RELOCS-NEXT: }
; RV64-OBJ-RELOCS: Section ({{.+}}) .rela.gcc_except_table {
; RV64-OBJ-RELOCS-NEXT: R_RISCV_ADD32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_SUB32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_ADD32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_SUB32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_CHERI_CAPABILITY .L_Z4testll$local 0x5C
; RV64-OBJ-RELOCS-NEXT: R_RISCV_ADD32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_SUB32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_ADD32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_SUB32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_CHERI_CAPABILITY .L_Z4testll$local 0x48
; RV64-OBJ-RELOCS-NEXT: R_RISCV_ADD32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_SUB32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_ADD32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_SUB32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_ADD32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_SUB32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_ADD32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_SUB32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_CHERI_CAPABILITY .L_Z5test2ll$local 0x48
; RV64-OBJ-RELOCS-NEXT: R_RISCV_ADD32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_SUB32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_ADD32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_SUB32 - 0x0
; RV64-OBJ-RELOCS-NEXT: R_RISCV_32_PCREL .L_ZTIl.DW.stub 0x0
; RV64-OBJ-RELOCS-NEXT: }

;; This should work with both -z text and -z notext
;; Check that .gcc_except_table ends up in the relro section and the relocations are correct
; RUN: ld.lld -shared %t.o -o %t.so -z notext
; RUN: llvm-readelf -r --section-mapping --sections --program-headers --cap-relocs %t.so | FileCheck %s --check-prefixes=HEADERS,MIPS-RELOCS
; RUN: ld.lld -shared %t.o -o %t.so -z text
; RUN: llvm-readelf -r --section-mapping %t.so
; RUN: llvm-readelf -r --section-mapping --sections --program-headers --cap-relocs %t.so | FileCheck %s --check-prefixes=HEADERS,MIPS-RELOCS

; HEADERS-LABEL: There are 10 program headers, starting at
; HEADERS-EMPTY:
; HEADERS-NEXT: Program Headers:
; HEADERS-NEXT: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
; HEADERS-NEXT: PHDR 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} R 0x8
; HEADERS-NEXT: LOAD 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} R 0x10000
; HEADERS-NEXT: LOAD 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} R E 0x10000
; HEADERS-NEXT: LOAD 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} RW 0x10000
; HEADERS-NEXT: LOAD 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} RW 0x10000
; HEADERS-NEXT: DYNAMIC 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} R 0x8
; HEADERS-NEXT: GNU_RELRO 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} R 0x1
; HEADERS-NEXT: GNU_STACK 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} RW 0x0
; HEADERS-NEXT: OPTIONS 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} R 0x8
; HEADERS-NEXT: ABIFLAGS 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} 0x{{.+}} R 0x8
; HEADERS-EMPTY:
; HEADERS-NEXT: Section to Segment mapping:
; HEADERS-NEXT: Segment Sections...
; HEADERS-NEXT: 00
; HEADERS-NEXT: 01 .MIPS.abiflags .MIPS.options .dynsym .hash .dynamic .dynstr .rel.dyn .rel.plt .eh_frame __cap_relocs {{$}}
; HEADERS-NEXT: 02 .text
; HEADERS-NEXT: 03 .gcc_except_table
; HEADERS-NEXT: 04 .data .captable .got
; HEADERS-NEXT: 05 .dynamic
; HEADERS-NEXT: 06 .gcc_except_table
; HEADERS-NEXT: 07
; HEADERS-NEXT: 08 .MIPS.options
; HEADERS-NEXT: 09 .MIPS.abiflags
; HEADERS-NEXT: None .bss .mdebug.abi64 .pdr .comment .symtab .shstrtab .strtab

; MIPS-RELOCS-LABEL: Relocation section '.rel.dyn' {{.+}} contains 2 entries:
; MIPS-RELOCS-NEXT: Offset Info Type Symbol's Value Symbol's Name
; MIPS-RELOCS-NEXT: R_MIPS_CHERI_CAPABILITY/R_MIPS_NONE/R_MIPS_NONE 0000000000000000 _ZTIl
; MIPS-RELOCS-NEXT: R_MIPS_CHERI_CAPABILITY/R_MIPS_NONE/R_MIPS_NONE 0000000000000000 __gxx_personality_v0
; MIPS-RELOCS-EMPTY:
; MIPS-RELOCS-NEXT: Relocation section '.rel.plt' at offset {{.+}} contains 3 entries:
; MIPS-RELOCS-NEXT: Offset Info Type Symbol's Value Symbol's Name
; MIPS-RELOCS-NEXT: R_MIPS_CHERI_CAPABILITY_CALL/R_MIPS_NONE/R_MIPS_NONE 0000000000000000 _Z11external_fnl
; MIPS-RELOCS-NEXT: R_MIPS_CHERI_CAPABILITY_CALL/R_MIPS_NONE/R_MIPS_NONE 0000000000000000 __cxa_begin_catch
; MIPS-RELOCS-NEXT: R_MIPS_CHERI_CAPABILITY_CALL/R_MIPS_NONE/R_MIPS_NONE 0000000000000000 __cxa_end_catch

;; Local relocations for exception handling:
; MIPS-RELOCS-NEXT: CHERI __cap_relocs [
; MIPS-RELOCS-NEXT: 0x02{{.+}} Base: 0x1{{.+}} (.L_Z4testll$local+128) Length: 160 Perms: Function
; MIPS-RELOCS-NEXT: 0x02{{.+}} Base: 0x1{{.+}} (.L_Z4testll$local+96) Length: 160 Perms: Function
; MIPS-RELOCS-NEXT: 0x02{{.+}} Base: 0x1{{.+}} (.L_Z5test2ll$local+96) Length: 168 Perms: Function
; MIPS-RELOCS-NEXT: ]

;; Should also emit __cap_relocs for RISC-V:
; RUN: ld.lld -shared %t-riscv64.o -o %t.so
; RUN: llvm-readelf -r --cap-relocs %t.so | FileCheck %s --check-prefixes=RV64-RELOCS
; RV64-RELOCS: CHERI __cap_relocs [
; RV64-RELOCS-NEXT: 0x002{{.+}} Base: 0x1{{.+}} (.L_Z4testll$local+92) Length: 116 Perms: Function
; RV64-RELOCS-NEXT: 0x002{{.+}} Base: 0x1{{.+}} (.L_Z4testll$local+72) Length: 116 Perms: Function
; RV64-RELOCS-NEXT: 0x002{{.+}} Base: 0x1{{.+}} (.L_Z5test2ll$local+72) Length: 124 Perms: Function
; RV64-RELOCS-NEXT: ]

; IR was generated from the following code:
; long external_fn(long arg);
;
; long test(long arg, long arg2) {
; long a = 0;
; long b = 0;
; try {
; a = external_fn(arg);
; } catch (...) {
; return -1;
; }
; try {
; b = external_fn(arg2);
; } catch (...) {
; return a;
; }
; return a + b;
; }
;
; long test2(long arg, long arg2) {
; try {
; return external_fn(arg) - external_fn(arg2);
; } catch (long &err) {
; return err;
; } catch (...) {
; return -1;
; }
; }

@_ZTIl = external dso_local addrspace(200) constant ptr addrspace(200)

define dso_local noundef i64 @_Z4testll(i64 noundef %arg, i64 noundef %arg2) local_unnamed_addr addrspace(200) uwtable personality ptr addrspace(200) @__gxx_personality_v0 {
entry:
%call = invoke noundef i64 @_Z11external_fnl(i64 noundef %arg)
to label %invoke.cont unwind label %lpad

invoke.cont:
%call3 = invoke noundef i64 @_Z11external_fnl(i64 noundef %arg2)
to label %invoke.cont2 unwind label %lpad1

lpad:
%0 = landingpad { ptr addrspace(200), i32 }
catch ptr addrspace(200) null
%1 = extractvalue { ptr addrspace(200), i32 } %0, 0
%2 = tail call ptr addrspace(200) @__cxa_begin_catch(ptr addrspace(200) %1) nounwind
tail call void @__cxa_end_catch()
br label %cleanup

invoke.cont2:
%add = add nsw i64 %call3, %call
br label %cleanup

lpad1:
%3 = landingpad { ptr addrspace(200), i32 }
catch ptr addrspace(200) null
%4 = extractvalue { ptr addrspace(200), i32 } %3, 0
%5 = tail call ptr addrspace(200) @__cxa_begin_catch(ptr addrspace(200) %4) nounwind
tail call void @__cxa_end_catch()
br label %cleanup

cleanup:
%retval.0 = phi i64 [ %add, %invoke.cont2 ], [ %call, %lpad1 ], [ -1, %lpad ]
ret i64 %retval.0
}

declare dso_local noundef i64 @_Z11external_fnl(i64 noundef) local_unnamed_addr addrspace(200)

declare dso_local i32 @__gxx_personality_v0(...) addrspace(200)

declare dso_local ptr addrspace(200) @__cxa_begin_catch(ptr addrspace(200)) local_unnamed_addr addrspace(200)

declare dso_local void @__cxa_end_catch() local_unnamed_addr addrspace(200)

; Function Attrs: mustprogress uwtable
define dso_local noundef i64 @_Z5test2ll(i64 noundef %arg, i64 noundef %arg2) local_unnamed_addr addrspace(200) #0 personality ptr addrspace(200) @__gxx_personality_v0 {
entry:
%call = invoke noundef i64 @_Z11external_fnl(i64 noundef %arg)
to label %invoke.cont unwind label %lpad

invoke.cont:
%call2 = invoke noundef i64 @_Z11external_fnl(i64 noundef %arg2)
to label %invoke.cont1 unwind label %lpad

invoke.cont1:
%sub = sub nsw i64 %call, %call2
br label %return

lpad:
%0 = landingpad { ptr addrspace(200), i32 }
catch ptr addrspace(200) @_ZTIl
catch ptr addrspace(200) null
%1 = extractvalue { ptr addrspace(200), i32 } %0, 0
%2 = extractvalue { ptr addrspace(200), i32 } %0, 1
%3 = tail call i32 @llvm.eh.typeid.for(ptr addrspacecast (ptr addrspace(200) @_ZTIl to ptr)) nounwind
%matches = icmp eq i32 %2, %3
%4 = tail call ptr addrspace(200) @__cxa_begin_catch(ptr addrspace(200) %1) nounwind
br i1 %matches, label %catch3, label %catch

catch3:
%5 = load i64, ptr addrspace(200) %4, align 8
tail call void @__cxa_end_catch() nounwind
br label %return

catch:
tail call void @__cxa_end_catch()
br label %return

return:
%retval.0 = phi i64 [ %sub, %invoke.cont1 ], [ %5, %catch3 ], [ -1, %catch ]
ret i64 %retval.0
}

declare i32 @llvm.eh.typeid.for(ptr) addrspace(200)
3 changes: 2 additions & 1 deletion lld/test/ELF/cheri/lit.local.cfg
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,8 @@ config.lld = lit.util.which('ld.lld', config.llvm_tools_dir)
# These substitutions rely on %clang, etc. so must come before even if clang isn't found
add_sub('%clang_link_purecap ', '%cheri_purecap_clang ' +
'-fuse-ld=' + config.lld + ' -nostdlib -Wl,-melf64btsmip_cheri_fbsd ')
local_llvm_config.add_cheri_tool_substitutions(['llvm-mc'])
local_llvm_config.use_llvm_tool("llc")
local_llvm_config.add_cheri_tool_substitutions(['llvm-mc', 'llc'])
local_llvm_config.use_clang(required=False)
if config.clang:
if lit_config.debug:
Expand Down
10 changes: 5 additions & 5 deletions llvm/include/llvm/CodeGen/AsmPrinter.h
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Original file line number Diff line number Diff line change
Expand Up @@ -199,11 +199,8 @@ class AsmPrinter : public MachineFunctionPass {
protected:
MCSymbol *CurrentFnBegin = nullptr;

/// The symbol used to represent the start of the current function for the
/// purpose of exception handling for pure-capability CHERI targets.
MCSymbol *CurrentFnBeginForEH = nullptr;

/// For dso_local functions, the current $local alias for the function.
/// Also used for exception handling for pure-capability CHERI targets.
MCSymbol *CurrentFnBeginLocal = nullptr;

/// A vector of all debug/EH info emitters we should use. This vector
Expand Down Expand Up @@ -329,7 +326,10 @@ class AsmPrinter : public MachineFunctionPass {
/// Similar to getSymbol() but preferred for references. On ELF, this uses a
/// local symbol if a reference to GV is guaranteed to be resolved to the
/// definition in the same module.
MCSymbol *getSymbolPreferLocal(const GlobalValue &GV) const;
/// If \p Force is set to true, return a local alias if possible even if the
/// normal heuristics say it is not beneficial.
MCSymbol *getSymbolPreferLocal(const GlobalValue &GV,
bool Force = false) const;

bool doesDwarfUseRelocationsAcrossSections() const {
return DwarfUsesRelocationsAcrossSections;
Expand Down
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