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[DebugInfo] Shorten legacy [s|z]ext dwarf expressions 

Take advantage of the emitConstu helper to emit slightly shorter dwarf
expressions to implement legacy [s|z]ext operations.
This commit is contained in:
Vedant Kumar 2020-10-21 09:22:13 -07:00
parent 9905346221
commit 2ce36ebca5
3 changed files with 5 additions and 8 deletions
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9
llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
View File

@ -638,14 +638,12 @@ void DwarfExpression::addFragmentOffset(const DIExpression *Expr) {
void DwarfExpression::emitLegacySExt(unsigned FromBits) {
// (((X >> (FromBits - 1)) * (~0)) << FromBits) | X
emitOp(dwarf::DW_OP_dup);
emitOp(dwarf::DW_OP_constu);
emitUnsigned(FromBits - 1);
emitConstu(FromBits - 1);
emitOp(dwarf::DW_OP_shr);
emitOp(dwarf::DW_OP_lit0);
emitOp(dwarf::DW_OP_not);
emitOp(dwarf::DW_OP_mul);
emitOp(dwarf::DW_OP_constu);
emitUnsigned(FromBits);
emitConstu(FromBits);
emitOp(dwarf::DW_OP_shl);
emitOp(dwarf::DW_OP_or);
}
@ -653,8 +651,7 @@ void DwarfExpression::emitLegacySExt(unsigned FromBits) {
void DwarfExpression::emitLegacyZExt(unsigned FromBits, unsigned ToBits) {
if (FromBits < 64) {
// X & ((1 << FromBits) - 1)
emitOp(dwarf::DW_OP_constu);
emitUnsigned((1ULL << FromBits) - 1);
emitConstu((1ULL << FromBits) - 1);
emitOp(dwarf::DW_OP_and);
} else {
addOpPiece(FromBits, 0);

2
llvm/test/DebugInfo/X86/convert-debugloc.ll
View File

@ -62,7 +62,7 @@
; NOCONV: DW_TAG_formal_parameter
; NOCONV: DW_TAG_variable
; NOCONV: DW_AT_location (
; NOCONV: {{.*}}, DW_OP_dup, DW_OP_constu 0x7, DW_OP_shr, DW_OP_lit0, DW_OP_not, DW_OP_mul, DW_OP_constu 0x8, DW_OP_shl, DW_OP_or, DW_OP_stack_value)
; NOCONV: {{.*}}, DW_OP_dup, DW_OP_lit7, DW_OP_shr, DW_OP_lit0, DW_OP_not, DW_OP_mul, DW_OP_lit8, DW_OP_shl, DW_OP_or, DW_OP_stack_value)
; NOCONV: DW_AT_name ("y")
; NOCONV: NULL
; NOCONV: DW_TAG_base_type

2
llvm/test/DebugInfo/X86/convert-inlined.ll
View File

@ -26,7 +26,7 @@
; DW4: DW_TAG_compile_unit
; DW4: DW_TAG_variable
; DW4: DW_AT_name ("global")
; DW4: DW_AT_location (DW_OP_addr 0x0, DW_OP_deref, DW_OP_dup, DW_OP_constu 0x7, DW_OP_shr, DW_OP_lit0, DW_OP_not, DW_OP_mul, DW_OP_constu 0x8, DW_OP_shl, DW_OP_or, DW_OP_stack_value)
; DW4: DW_AT_location (DW_OP_addr 0x0, DW_OP_deref, DW_OP_dup, DW_OP_lit7, DW_OP_shr, DW_OP_lit0, DW_OP_not, DW_OP_mul, DW_OP_lit8, DW_OP_shl, DW_OP_or, DW_OP_stack_value)
; DW4: DW_TAG_base_type
; DW4: DW_AT_name ("int")
; DW4: NULL