mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-27 13:30:05 +00:00
MC/Expr: Implemnt more aggressive folding during symbol evaluation using
IsSymbolRefDifferenceFullyResolved(). For example, we will now fold away something like: -- _a: ... L0: ... L1: ... .long (L1 - L0) / 2 -- git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122043 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Daniel Dunbar
parent
b87422778c
commit
17304b3489
@ -271,6 +271,25 @@ bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout *Layout,
|
||||
return true;
|
||||
}
|
||||
|
||||
/// \brief Helper method for \see EvaluateSymbolAdd().
|
||||
static void AttemptToFoldSymbolOffsetDifference(const MCAsmLayout *Layout,
|
||||
const MCSymbolRefExpr *&A,
|
||||
const MCSymbolRefExpr *&B,
|
||||
int64_t &Addend) {
|
||||
const MCAssembler &Asm = Layout->getAssembler();
|
||||
|
||||
if (A && B &&
|
||||
Asm.getWriter().IsSymbolRefDifferenceFullyResolved(Asm, A, B)) {
|
||||
// Eagerly evaluate.
|
||||
Addend += (Layout->getSymbolOffset(&Asm.getSymbolData(A->getSymbol())) -
|
||||
Layout->getSymbolOffset(&Asm.getSymbolData(B->getSymbol())));
|
||||
|
||||
// Clear the symbol expr pointers to indicate we have folded these
|
||||
// operands.
|
||||
A = B = 0;
|
||||
}
|
||||
}
|
||||
|
||||
/// \brief Evaluate the result of an add between (conceptually) two MCValues.
|
||||
///
|
||||
/// This routine conceptually attempts to construct an MCValue:
|
||||
@ -300,20 +319,37 @@ static bool EvaluateSymbolicAdd(const MCAsmLayout *Layout,
|
||||
// Fold the result constant immediately.
|
||||
int64_t Result_Cst = LHS_Cst + RHS_Cst;
|
||||
|
||||
// If we have a layout, we can fold resolved differences.
|
||||
if (Layout) {
|
||||
// First, fold out any differences which are fully resolved. By
|
||||
// reassociating terms in
|
||||
// Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
|
||||
// we have the four possible differences:
|
||||
// (LHS_A - LHS_B),
|
||||
// (LHS_A - RHS_B),
|
||||
// (RHS_A - LHS_B),
|
||||
// (RHS_A - RHS_B).
|
||||
// Since we are attempting to be as aggresive as possible about folding, we
|
||||
// attempt to evaluate each possible alternative.
|
||||
AttemptToFoldSymbolOffsetDifference(Layout, LHS_A, LHS_B, Result_Cst);
|
||||
AttemptToFoldSymbolOffsetDifference(Layout, LHS_A, RHS_B, Result_Cst);
|
||||
AttemptToFoldSymbolOffsetDifference(Layout, RHS_A, LHS_B, Result_Cst);
|
||||
AttemptToFoldSymbolOffsetDifference(Layout, RHS_A, RHS_B, Result_Cst);
|
||||
}
|
||||
|
||||
// We can't represent the addition or subtraction of two symbols.
|
||||
if ((LHS_A && RHS_A) || (LHS_B && RHS_B))
|
||||
return false;
|
||||
|
||||
// At this point, we have at most one additive symbol and one subtractive
|
||||
// symbol -- find them.
|
||||
const MCSymbolRefExpr *A = LHS_A ? LHS_A : RHS_A;
|
||||
const MCSymbolRefExpr *B = LHS_B ? LHS_B : RHS_B;
|
||||
if (B) {
|
||||
// If we have a negated symbol, then we must have also have a non-negated
|
||||
// symbol in order to encode the expression. We can do this check later to
|
||||
// permit expressions which eventually fold to a representable form -- such
|
||||
// as (a + (0 - b)) -- if necessary.
|
||||
if (!A)
|
||||
return false;
|
||||
}
|
||||
|
||||
// If we have a negated symbol, then we must have also have a non-negated
|
||||
// symbol in order to encode the expression.
|
||||
if (B && !A)
|
||||
return false;
|
||||
|
||||
// Absolutize symbol differences between defined symbols when we have a
|
||||
// layout object and the target requests it.
|
||||
|
||||
129
test/MC/MachO/darwin-complex-difference.s
Normal file
129
test/MC/MachO/darwin-complex-difference.s
Normal file
@ -0,0 +1,129 @@
|
||||
// RUN: llvm-mc -triple x86_64-apple-darwin10 %s -filetype=obj -o %t.o
|
||||
// RUN: macho-dump --dump-section-data < %t.o > %t.dump
|
||||
// RUN: FileCheck < %t.dump %s
|
||||
|
||||
_a:
|
||||
L0:
|
||||
.long 1
|
||||
L1:
|
||||
.long 2
|
||||
.long _c - _d + 4
|
||||
.long (_c - L0) - (_d - L1) // == (_c - _d) + (L1 - L0)
|
||||
// == (_c - _d + 4)
|
||||
_c:
|
||||
.long 0
|
||||
_d:
|
||||
.long 0
|
||||
|
||||
// CHECK: ('cputype', 16777223)
|
||||
// CHECK: ('cpusubtype', 3)
|
||||
// CHECK: ('filetype', 1)
|
||||
// CHECK: ('num_load_commands', 3)
|
||||
// CHECK: ('load_commands_size', 256)
|
||||
// CHECK: ('flag', 0)
|
||||
// CHECK: ('reserved', 0)
|
||||
// CHECK: ('load_commands', [
|
||||
// CHECK: # Load Command 0
|
||||
// CHECK: (('command', 25)
|
||||
// CHECK: ('size', 152)
|
||||
// CHECK: ('segment_name', '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
|
||||
// CHECK: ('vm_addr', 0)
|
||||
// CHECK: ('vm_size', 24)
|
||||
// CHECK: ('file_offset', 288)
|
||||
// CHECK: ('file_size', 24)
|
||||
// CHECK: ('maxprot', 7)
|
||||
// CHECK: ('initprot', 7)
|
||||
// CHECK: ('num_sections', 1)
|
||||
// CHECK: ('flags', 0)
|
||||
// CHECK: ('sections', [
|
||||
// CHECK: # Section 0
|
||||
// CHECK: (('section_name', '__text\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
|
||||
// CHECK: ('segment_name', '__TEXT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
|
||||
// CHECK: ('address', 0)
|
||||
// CHECK: ('size', 24)
|
||||
// CHECK: ('offset', 288)
|
||||
// CHECK: ('alignment', 0)
|
||||
// CHECK: ('reloc_offset', 312)
|
||||
// CHECK: ('num_reloc', 4)
|
||||
// CHECK: ('flags', 0x80000000)
|
||||
// CHECK: ('reserved1', 0)
|
||||
// CHECK: ('reserved2', 0)
|
||||
// CHECK: ('reserved3', 0)
|
||||
// CHECK: ),
|
||||
// CHECK: ('_relocations', [
|
||||
// CHECK: # Relocation 0
|
||||
// CHECK: (('word-0', 0xc),
|
||||
// CHECK: ('word-1', 0x5c000002)),
|
||||
// CHECK: # Relocation 1
|
||||
// CHECK: (('word-0', 0xc),
|
||||
// CHECK: ('word-1', 0xc000001)),
|
||||
// CHECK: # Relocation 2
|
||||
// CHECK: (('word-0', 0x8),
|
||||
// CHECK: ('word-1', 0x5c000002)),
|
||||
// CHECK: # Relocation 3
|
||||
// CHECK: (('word-0', 0x8),
|
||||
// CHECK: ('word-1', 0xc000001)),
|
||||
// CHECK: ])
|
||||
// CHECK: ('_section_data', '01000000 02000000 04000000 04000000 00000000 00000000')
|
||||
// CHECK: ])
|
||||
// CHECK: ),
|
||||
// CHECK: # Load Command 1
|
||||
// CHECK: (('command', 2)
|
||||
// CHECK: ('size', 24)
|
||||
// CHECK: ('symoff', 344)
|
||||
// CHECK: ('nsyms', 3)
|
||||
// CHECK: ('stroff', 392)
|
||||
// CHECK: ('strsize', 12)
|
||||
// CHECK: ('_string_data', '\x00_a\x00_c\x00_d\x00\x00\x00')
|
||||
// CHECK: ('_symbols', [
|
||||
// CHECK: # Symbol 0
|
||||
// CHECK: (('n_strx', 1)
|
||||
// CHECK: ('n_type', 0xe)
|
||||
// CHECK: ('n_sect', 1)
|
||||
// CHECK: ('n_desc', 0)
|
||||
// CHECK: ('n_value', 0)
|
||||
// CHECK: ('_string', '_a')
|
||||
// CHECK: ),
|
||||
// CHECK: # Symbol 1
|
||||
// CHECK: (('n_strx', 4)
|
||||
// CHECK: ('n_type', 0xe)
|
||||
// CHECK: ('n_sect', 1)
|
||||
// CHECK: ('n_desc', 0)
|
||||
// CHECK: ('n_value', 16)
|
||||
// CHECK: ('_string', '_c')
|
||||
// CHECK: ),
|
||||
// CHECK: # Symbol 2
|
||||
// CHECK: (('n_strx', 7)
|
||||
// CHECK: ('n_type', 0xe)
|
||||
// CHECK: ('n_sect', 1)
|
||||
// CHECK: ('n_desc', 0)
|
||||
// CHECK: ('n_value', 20)
|
||||
// CHECK: ('_string', '_d')
|
||||
// CHECK: ),
|
||||
// CHECK: ])
|
||||
// CHECK: ),
|
||||
// CHECK: # Load Command 2
|
||||
// CHECK: (('command', 11)
|
||||
// CHECK: ('size', 80)
|
||||
// CHECK: ('ilocalsym', 0)
|
||||
// CHECK: ('nlocalsym', 3)
|
||||
// CHECK: ('iextdefsym', 3)
|
||||
// CHECK: ('nextdefsym', 0)
|
||||
// CHECK: ('iundefsym', 3)
|
||||
// CHECK: ('nundefsym', 0)
|
||||
// CHECK: ('tocoff', 0)
|
||||
// CHECK: ('ntoc', 0)
|
||||
// CHECK: ('modtaboff', 0)
|
||||
// CHECK: ('nmodtab', 0)
|
||||
// CHECK: ('extrefsymoff', 0)
|
||||
// CHECK: ('nextrefsyms', 0)
|
||||
// CHECK: ('indirectsymoff', 0)
|
||||
// CHECK: ('nindirectsyms', 0)
|
||||
// CHECK: ('extreloff', 0)
|
||||
// CHECK: ('nextrel', 0)
|
||||
// CHECK: ('locreloff', 0)
|
||||
// CHECK: ('nlocrel', 0)
|
||||
// CHECK: ('_indirect_symbols', [
|
||||
// CHECK: ])
|
||||
// CHECK: ),
|
||||
// CHECK: ])
|
||||
Loading…
Reference in New Issue
Block a user