[llvm] r369755 - [mips] Do not include offset into `%got` expression for global symbols
Simon Atanasyan via llvm-commits
llvm-commits at lists.llvm.org
Fri Aug 23 06:36:14 PDT 2019
Author: atanasyan
Date: Fri Aug 23 06:36:14 2019
New Revision: 369755
URL: http://llvm.org/viewvc/llvm-project?rev=369755&view=rev
Log:
[mips] Do not include offset into `%got` expression for global symbols
Now pseudo instruction `la $6, symbol+8($6)` is expanding into the following
chain of commands:
```
lw $1, %got(symbol+8)($gp)
addiu $1, $1, 8
addu $6, $1, $6
```
This is incorrect. When a linker handles the `R_MIPS_GOT16` relocation,
it does not expect to get any addend and breaks on assertion. Otherwise
it has to create new GOT entry for each unique "sym + offset" pair.
Offset for a global symbol should be added to result of loading GOT
entry by a separate `add` command.
The patch fixes the problem by stripping off an offset from the expression
passed to the `%got`. That's interesting that even current code inserts
a separate `add` command.
Differential Revision: https://reviews.llvm.org/D66552
Modified:
llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
llvm/trunk/test/MC/Mips/macro-la-pic.s
llvm/trunk/test/MC/Mips/mips-expansions.s
Modified: llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp?rev=369755&r1=369754&r2=369755&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp (original)
+++ llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp Fri Aug 23 06:36:14 2019
@@ -2884,16 +2884,18 @@ bool MipsAsmParser::loadAndAddSymbolAddr
return true;
}
+ bool IsLocalSym =
+ Res.getSymA()->getSymbol().isInSection() ||
+ Res.getSymA()->getSymbol().isTemporary() ||
+ (Res.getSymA()->getSymbol().isELF() &&
+ cast<MCSymbolELF>(Res.getSymA()->getSymbol()).getBinding() ==
+ ELF::STB_LOCAL);
+
// The case where the result register is $25 is somewhat special. If the
// symbol in the final relocation is external and not modified with a
// constant then we must use R_MIPS_CALL16 instead of R_MIPS_GOT16.
if ((DstReg == Mips::T9 || DstReg == Mips::T9_64) && !UseSrcReg &&
- Res.getConstant() == 0 &&
- !(Res.getSymA()->getSymbol().isInSection() ||
- Res.getSymA()->getSymbol().isTemporary() ||
- (Res.getSymA()->getSymbol().isELF() &&
- cast<MCSymbolELF>(Res.getSymA()->getSymbol()).getBinding() ==
- ELF::STB_LOCAL))) {
+ Res.getConstant() == 0 && !IsLocalSym) {
const MCExpr *CallExpr =
MipsMCExpr::create(MipsMCExpr::MEK_GOT_CALL, SymExpr, getContext());
TOut.emitRRX(Mips::LW, DstReg, GPReg, MCOperand::createExpr(CallExpr),
@@ -2902,8 +2904,8 @@ bool MipsAsmParser::loadAndAddSymbolAddr
}
// The remaining cases are:
- // External GOT: lw $tmp, %got(symbol+offset)($gp)
- // >addiu $tmp, $tmp, %lo(offset)
+ // External GOT: lw $tmp, %got(symbol)($gp)
+ // >addiu $tmp, $tmp, offset
// >addiu $rd, $tmp, $rs
// Local GOT: lw $tmp, %got(symbol+offset)($gp)
// addiu $tmp, $tmp, %lo(symbol+offset)($gp)
@@ -2911,17 +2913,19 @@ bool MipsAsmParser::loadAndAddSymbolAddr
// The addiu's marked with a '>' may be omitted if they are redundant. If
// this happens then the last instruction must use $rd as the result
// register.
- const MipsMCExpr *GotExpr =
- MipsMCExpr::create(MipsMCExpr::MEK_GOT, SymExpr, getContext());
+ const MipsMCExpr *GotExpr = nullptr;
const MCExpr *LoExpr = nullptr;
- if (Res.getSymA()->getSymbol().isInSection() ||
- Res.getSymA()->getSymbol().isTemporary())
+ if (IsLocalSym) {
+ GotExpr = MipsMCExpr::create(MipsMCExpr::MEK_GOT, SymExpr, getContext());
LoExpr = MipsMCExpr::create(MipsMCExpr::MEK_LO, SymExpr, getContext());
- else if (Res.getConstant() != 0) {
+ } else {
// External symbols fully resolve the symbol with just the %got(symbol)
// but we must still account for any offset to the symbol for expressions
// like symbol+8.
- LoExpr = MCConstantExpr::create(Res.getConstant(), getContext());
+ GotExpr =
+ MipsMCExpr::create(MipsMCExpr::MEK_GOT, Res.getSymA(), getContext());
+ if (Res.getConstant() != 0)
+ LoExpr = MCConstantExpr::create(Res.getConstant(), getContext());
}
unsigned TmpReg = DstReg;
Modified: llvm/trunk/test/MC/Mips/macro-la-pic.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Mips/macro-la-pic.s?rev=369755&r1=369754&r2=369755&view=diff
==============================================================================
--- llvm/trunk/test/MC/Mips/macro-la-pic.s (original)
+++ llvm/trunk/test/MC/Mips/macro-la-pic.s Fri Aug 23 06:36:14 2019
@@ -14,13 +14,15 @@ la $5, symbol($6) # CHECK: lw $5, %g
la $6, symbol($6) # CHECK: lw $1, %got(symbol)($gp) # encoding: [0x8f,0x81,A,A]
# CHECK: # fixup A - offset: 0, value: %got(symbol), kind: fixup_Mips_GOT
# CHECK: addu $6, $1, $6 # encoding: [0x00,0x26,0x30,0x21]
-la $5, symbol+8 # CHECK: lw $5, %got(symbol+8)($gp) # encoding: [0x8f,0x85,A,A]
- # CHECK: # fixup A - offset: 0, value: %got(symbol+8), kind: fixup_Mips_GOT
-la $5, symbol+8($6) # CHECK: lw $5, %got(symbol+8)($gp) # encoding: [0x8f,0x85,A,A]
- # CHECK: # fixup A - offset: 0, value: %got(symbol+8), kind: fixup_Mips_GOT
+la $5, symbol+8 # CHECK: lw $5, %got(symbol)($gp) # encoding: [0x8f,0x85,A,A]
+ # CHECK: # fixup A - offset: 0, value: %got(symbol), kind: fixup_Mips_GOT
+ # CHECK: addiu $5, $5, 8 # encoding: [0x24,0xa5,0x00,0x08]
+la $5, symbol+8($6) # CHECK: lw $5, %got(symbol)($gp) # encoding: [0x8f,0x85,A,A]
+ # CHECK: # fixup A - offset: 0, value: %got(symbol), kind: fixup_Mips_GOT
+ # CHECK: addiu $5, $5, 8 # encoding: [0x24,0xa5,0x00,0x08]
# CHECK: addu $5, $5, $6 # encoding: [0x00,0xa6,0x28,0x21]
-la $6, symbol+8($6) # CHECK: lw $1, %got(symbol+8)($gp) # encoding: [0x8f,0x81,A,A]
- # CHECK: # fixup A - offset: 0, value: %got(symbol+8), kind: fixup_Mips_GOT
+la $6, symbol+8($6) # CHECK: lw $1, %got(symbol)($gp) # encoding: [0x8f,0x81,A,A]
+ # CHECK: # fixup A - offset: 0, value: %got(symbol), kind: fixup_Mips_GOT
# CHECK: addiu $1, $1, 8 # encoding: [0x24,0x21,0x00,0x08]
# CHECK: addu $6, $1, $6 # encoding: [0x00,0x26,0x30,0x21]
la $5, 1f # CHECK: lw $5, %got($tmp0)($gp) # encoding: [0x8f,0x85,A,A]
@@ -38,13 +40,15 @@ la $25, symbol($6) # CHECK: lw $25, %
la $25, symbol($25) # CHECK: lw $1, %got(symbol)($gp) # encoding: [0x8f,0x81,A,A]
# CHECK: # fixup A - offset: 0, value: %got(symbol), kind: fixup_Mips_GOT
# CHECK: addu $25, $1, $25 # encoding: [0x00,0x39,0xc8,0x21]
-la $25, symbol+8 # CHECK: lw $25, %got(symbol+8)($gp) # encoding: [0x8f,0x99,A,A]
- # CHECK: # fixup A - offset: 0, value: %got(symbol+8), kind: fixup_Mips_GOT
-la $25, symbol+8($6) # CHECK: lw $25, %got(symbol+8)($gp) # encoding: [0x8f,0x99,A,A]
- # CHECK: # fixup A - offset: 0, value: %got(symbol+8), kind: fixup_Mips_GOT
+la $25, symbol+8 # CHECK: lw $25, %got(symbol)($gp) # encoding: [0x8f,0x99,A,A]
+ # CHECK: # fixup A - offset: 0, value: %got(symbol), kind: fixup_Mips_GOT
+ # CHECK: addiu $25, $25, 8 # encoding: [0x27,0x39,0x00,0x08]
+la $25, symbol+8($6) # CHECK: lw $25, %got(symbol)($gp) # encoding: [0x8f,0x99,A,A]
+ # CHECK: # fixup A - offset: 0, value: %got(symbol), kind: fixup_Mips_GOT
+ # CHECK: addiu $25, $25, 8 # encoding: [0x27,0x39,0x00,0x08]
# CHECK: addu $25, $25, $6 # encoding: [0x03,0x26,0xc8,0x21]
-la $25, symbol+8($25) # CHECK: lw $1, %got(symbol+8)($gp) # encoding: [0x8f,0x81,A,A]
- # CHECK: # fixup A - offset: 0, value: %got(symbol+8), kind: fixup_Mips_GOT
+la $25, symbol+8($25) # CHECK: lw $1, %got(symbol)($gp) # encoding: [0x8f,0x81,A,A]
+ # CHECK: # fixup A - offset: 0, value: %got(symbol), kind: fixup_Mips_GOT
# CHECK: addiu $1, $1, 8 # encoding: [0x24,0x21,0x00,0x08]
# CHECK: addu $25, $1, $25 # encoding: [0x00,0x39,0xc8,0x21]
la $25, 1f # CHECK: lw $25, %got($tmp1)($gp) # encoding: [0x8f,0x99,A,A]
Modified: llvm/trunk/test/MC/Mips/mips-expansions.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Mips/mips-expansions.s?rev=369755&r1=369754&r2=369755&view=diff
==============================================================================
--- llvm/trunk/test/MC/Mips/mips-expansions.s (original)
+++ llvm/trunk/test/MC/Mips/mips-expansions.s Fri Aug 23 06:36:14 2019
@@ -144,13 +144,13 @@
# CHECK-LE: sw $10, -7616($1) # encoding: [0x40,0xe2,0x2a,0xac]
lw $8, symbol+8
-# CHECK-LE: lw $8, %got(symbol+8)($gp) # encoding: [A,A,0x88,0x8f]
-# CHECK-LE: # fixup A - offset: 0, value: %got(symbol+8), kind: fixup_Mips_GOT
+# CHECK-LE: lw $8, %got(symbol)($gp) # encoding: [A,A,0x88,0x8f]
+# CHECK-LE: # fixup A - offset: 0, value: %got(symbol), kind: fixup_Mips_GOT
# CHECK-LE: addiu $8, $8, 8 # encoding: [0x08,0x00,0x08,0x25]
# CHECK-LE: lw $8, 0($8) # encoding: [0x00,0x00,0x08,0x8d]
sw $8, symbol+8
-# CHECK-LE: lw $1, %got(symbol+8)($gp) # encoding: [A,A,0x81,0x8f]
-# CHECK-LE: # fixup A - offset: 0, value: %got(symbol+8), kind: fixup_Mips_GOT
+# CHECK-LE: lw $1, %got(symbol)($gp) # encoding: [A,A,0x81,0x8f]
+# CHECK-LE: # fixup A - offset: 0, value: %got(symbol), kind: fixup_Mips_GOT
# CHECK-LE: addiu $1, $1, 8 # encoding: [0x08,0x00,0x21,0x24]
# CHECK-LE: sw $8, 0($1) # encoding: [0x00,0x00,0x28,0xac]
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