MipsAsmParser/O32: Don't add redundant $ to $-prefixed symbol in the la macro #80644

wzssyqa · 2024-02-05T08:21:58Z

When parsing the la macro, we add a duplicate $ prefix in getOrCreateSymbol,
leading to error: Undefined temporary symbol $$yy for code like:

xx:
	la	$2,$yy
$yy:
	nop

Remove the duplicate prefix.

In addition, recognize .L-prefixed symbols as local for O32.

See: #65020.

llvmbot · 2024-02-05T08:22:26Z

@llvm/pr-subscribers-mc

Author: YunQiang Su (wzssyqa)

Changes

For asm code like:
xx:
la $2,$yy
$yy:
nop

MIPS O32 use $ as PrivateGlobalPrefix, while another $ is added for getOrCreateSymbol, thus:
error: Undefined temporary symbol $$yy

We also set symbols that starts with .L as local for O32.

See: #65020.

Full diff: https://github.com/llvm/llvm-project/pull/80644.diff

2 Files Affected:

(modified) llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp (+6-1)
(added) llvm/test/MC/Mips/macro-la-local.s (+23)

diff --git a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
index 3c673ae938fde..2ddd8a6f31756 100644
--- a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -2920,6 +2920,11 @@ bool MipsAsmParser::loadAndAddSymbolAddress(const MCExpr *SymExpr,
         (Res.getSymA()->getSymbol().isELF() &&
          cast<MCSymbolELF>(Res.getSymA()->getSymbol()).getBinding() ==
              ELF::STB_LOCAL);
+    if (!IsLocalSym && ABI.IsO32()) {
+      // PrivateGlobalPrefix for O32 is '$', while we support '.L' anyway.
+      if (Res.getSymA()->getSymbol().getName().starts_with(".L"))
+        IsLocalSym = true;
+    }
     bool UseXGOT = STI->hasFeature(Mips::FeatureXGOT) && !IsLocalSym;
 
     // The case where the result register is $25 is somewhat special. If the
@@ -6359,7 +6364,7 @@ bool MipsAsmParser::parseOperand(OperandVector &Operands, StringRef Mnemonic) {
       return true;
 
     SMLoc E = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
-    MCSymbol *Sym = getContext().getOrCreateSymbol("$" + Identifier);
+    MCSymbol *Sym = getContext().getOrCreateSymbol(Identifier);
     // Otherwise create a symbol reference.
     const MCExpr *SymRef =
         MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_None, getContext());
diff --git a/llvm/test/MC/Mips/macro-la-local.s b/llvm/test/MC/Mips/macro-la-local.s
new file mode 100644
index 0000000000000..14c8e1b689ac9
--- /dev/null
+++ b/llvm/test/MC/Mips/macro-la-local.s
@@ -0,0 +1,23 @@
+# RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r2 | \
+# RUN:   FileCheck %s --check-prefixes=CHECK
+# RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r6 | \
+# RUN:   FileCheck %s --check-prefixes=CHECK
+
+	.text
+	.abicalls
+	.option	pic2
+xx:
+	la	$2,.Lhello #CHECK: lw      $2, %got(.Lhello)($gp)          # encoding: [0x8f,0x82,A,A]
+                           #CHECK: #   fixup A - offset: 0, value: %got(.Lhello), kind: fixup_Mips_GOT
+                           #CHECK: addiu   $2, $2, %lo(.Lhello)            # encoding: [0x24,0x42,A,A]
+                           #CHECK: #   fixup A - offset: 0, value: %lo(.Lhello), kind: fixup_Mips_LO16
+
+	la	$2,$hello2 #CHECK: lw      $2, %got($hello2)($gp)          # encoding: [0x8f,0x82,A,A]
+                           #CHECK: #   fixup A - offset: 0, value: %got($hello2), kind: fixup_Mips_GOT
+                           #CHECK: addiu   $2, $2, %lo($hello2)            # encoding: [0x24,0x42,A,A]
+                           #CHECK: #   fixup A - offset: 0, value: %lo($hello2), kind: fixup_Mips_LO16
+	.rdata
+.Lhello:
+	.asciz "Hello world\n"
+$hello2:
+	.asciz "Hello world\n"

wzssyqa · 2024-02-06T01:46:17Z

@MaskRay @brad0

MaskRay · 2024-02-13T08:20:36Z

llvm/test/MC/Mips/macro-la-local.s

+	.abicalls
+	.option	pic2
+xx:
+	la	$2,.Lhello #CHECK: lw      $2, %got(.Lhello)($gp)          # encoding: [0x8f,0x82,A,A]


# CHECK: lw ... # CHECK-NEXT: fixup A ... # CHECK-NEXT: ... la $2, $hello2

MaskRay · 2024-02-13T08:29:29Z

llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp

@@ -2920,6 +2920,11 @@ bool MipsAsmParser::loadAndAddSymbolAddress(const MCExpr *SymExpr,
        (Res.getSymA()->getSymbol().isELF() &&
         cast<MCSymbolELF>(Res.getSymA()->getSymbol()).getBinding() ==
             ELF::STB_LOCAL);
+    if (!IsLocalSym && ABI.IsO32()) {
+      // PrivateGlobalPrefix for O32 is '$', while we support '.L' anyway.


This comment is confusing.

// For O32, "$"-prefixed symbols are recognized as temporary while .L-prefixed symbols are not (PrivateGlobalPrefix is "$"). Recognize ".L" manually.

MaskRay · 2024-02-13T08:31:00Z

llvm/test/MC/Mips/macro-la-local.s

@@ -0,0 +1,23 @@
+# RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r2 | \


remove -unknown-linux whenever applicable, to emphasize that this is generic ELF behavior.

github-actions · 2024-02-13T08:37:39Z

✅ With the latest revision this PR passed the C/C++ code formatter.

MaskRay · 2024-02-13T08:42:40Z

Suggested description:

When parsing the la macro, we add a duplicate $ prefix in getOrCreateSymbol,
leading to error: Undefined temporary symbol $$yy for code like:

xx:
	la	$2,$yy
$yy:
	nop

Remove the duplicate prefix.

In addition, recognize .L-prefixed symbols as local for O32.

For asm code like: xx: la $2,$yy $yy: nop MIPS O32 use `$` as PrivateGlobalPrefix, while another `$` is added for getOrCreateSymbol, thus: error: Undefined temporary symbol $$yy We also set symbols that starts with `.L` as local for O32. See: llvm#65020.

…la macro (llvm#80644) When parsing the `la` macro, we add a duplicate `$` prefix in `getOrCreateSymbol`, leading to `error: Undefined temporary symbol $$yy` for code like: ``` xx: la $2,$yy $yy: nop ``` Remove the duplicate prefix. In addition, recognize `.L`-prefixed symbols as local for O32. See: llvm#65020. --------- Co-authored-by: Fangrui Song <i@maskray.me> (cherry picked from commit c007fbb)

llvmbot added the mc Machine (object) code label Feb 5, 2024

wzssyqa force-pushed the local_for_asm branch from 69163b8 to 1c6dccc Compare February 6, 2024 01:19

MaskRay approved these changes Feb 13, 2024

View reviewed changes

wzssyqa and others added 4 commits February 13, 2024 21:56

Update MipsAsmParser.cpp

c8f05b1

Update MipsAsmParser.cpp

a760ac7

Fold tests into macro-la-pic.s

800d8be

MaskRay changed the title ~~MIPS/Asm/O32: Don't add another $ to PrivateGlobal symbol~~ MipsAsmParser/O32: Don't add redundant $ to $-prefixed symbol in the la macro Feb 14, 2024

MaskRay force-pushed the local_for_asm branch from 0b3d613 to 800d8be Compare February 14, 2024 06:09

MaskRay merged commit c007fbb into llvm:main Feb 14, 2024

brad0 mentioned this pull request Feb 15, 2024

Merge c007fbb19879f9b597b47ae772c53e53cdc65f29 into 18.x #81809

Closed

wzssyqa deleted the local_for_asm branch April 2, 2024 06:52

pointhex mentioned this pull request May 7, 2024

getStyleDiagHandler #91314

Closed

aemerson mentioned this pull request May 9, 2024

release/18.x: [AArc64][GlobalISel] Fix legalizer assert for G_INSERT_VECTOR_ELT - manual merge #91672

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		@@ -0,0 +1,23 @@
		# RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r2 \| \

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