diff options
Diffstat (limited to '0010-Backport-Mips-MC-AttemptToFoldSymbolOffsetDifference-revert-isMicroMips-special-case.patch')
| -rw-r--r-- | 0010-Backport-Mips-MC-AttemptToFoldSymbolOffsetDifference-revert-isMicroMips-special-case.patch | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/0010-Backport-Mips-MC-AttemptToFoldSymbolOffsetDifference-revert-isMicroMips-special-case.patch b/0010-Backport-Mips-MC-AttemptToFoldSymbolOffsetDifference-revert-isMicroMips-special-case.patch new file mode 100644 index 0000000..1d370ee --- /dev/null +++ b/0010-Backport-Mips-MC-AttemptToFoldSymbolOffsetDifference-revert-isMicroMips-special-case.patch @@ -0,0 +1,135 @@ +From 3b777f98a3997f338919af7ff1ef8a6fd07f76a0 Mon Sep 17 00:00:00 2001 +From: Fangrui Song <i@maskray.me> +Date: Wed, 16 Aug 2023 23:11:59 -0700 +Subject: [PATCH 14/14] [Mips][MC] AttemptToFoldSymbolOffsetDifference: revert + isMicroMips special case + +D52985/D57677 added a .gcc_except_table workaround, but the new behavior +doesn't match GNU assembler. +``` +void foo(); +int bar() { + foo(); + try { throw 1; } + catch (int) { return 1; } + return 0; +} + +clang --target=mipsel-linux-gnu -mmicromips -S a.cc +mipsel-linux-gnu-gcc -mmicromips -c a.s -o gnu.o + +.uleb128 ($cst_end0)-($cst_begin0) // bit 0 is not forced to 1 +.uleb128 ($func_begin0)-($func_begin0) // bit 0 is not forced to 1 +``` + +I have inspected `.gcc_except_table` output by `mipsel-linux-gnu-gcc -mmicromips -c a.cc`. +The `.uleb128` values are not forced to set the least significant bit. + +In addition, D57677's adjustment (even->odd) to CodeGen/Mips/micromips-b-range.ll is wrong. +PC-relative `.long func - .` values will differ from GNU assembler as well. + +The original intention of D52985 seems unclear to me. I think whatever +goal it wants to achieve should be moved to an upper layer. + +This isMicroMips special case has caused problems to fix MCAssembler::relaxLEB to use evaluateAsAbsolute instead of evaluateKnownAbsolute, +which is needed to proper support R_RISCV_SET_ULEB128/R_RISCV_SUB_ULEB128. + +Differential Revision: https://reviews.llvm.org/D157655 + +(cherry picked from commit 4c89277095ee7cda3d20e0f5f18b384212069778) +Change-Id: Iedd73e0c61856c30fde442309fc16d4327829f1a +--- + llvm/lib/MC/MCExpr.cpp | 5 ----- + llvm/test/CodeGen/Mips/micromips-b-range.ll | 8 ++++---- + llvm/test/CodeGen/Mips/micromips-gcc-except-table.ll | 2 +- + llvm/test/DebugInfo/Mips/eh_frame.ll | 4 ++-- + 4 files changed, 7 insertions(+), 12 deletions(-) + +diff --git a/llvm/lib/MC/MCExpr.cpp b/llvm/lib/MC/MCExpr.cpp +index 79808a58d81c..c9ff1865cf91 100644 +--- a/llvm/lib/MC/MCExpr.cpp ++++ b/llvm/lib/MC/MCExpr.cpp +@@ -611,11 +611,6 @@ static void AttemptToFoldSymbolOffsetDifference( + if (Asm->isThumbFunc(&SA)) + Addend |= 1; + +- // If symbol is labeled as micromips, we set low-bit to ensure +- // correct offset in .gcc_except_table +- if (Asm->getBackend().isMicroMips(&SA)) +- Addend |= 1; +- + // Clear the symbol expr pointers to indicate we have folded these + // operands. + A = B = nullptr; +diff --git a/llvm/test/CodeGen/Mips/micromips-b-range.ll b/llvm/test/CodeGen/Mips/micromips-b-range.ll +index 064afff3da0e..81d1c04208cc 100644 +--- a/llvm/test/CodeGen/Mips/micromips-b-range.ll ++++ b/llvm/test/CodeGen/Mips/micromips-b-range.ll +@@ -13,7 +13,7 @@ + ; CHECK-NEXT: 1e: fb fd 00 00 sw $ra, 0($sp) + ; CHECK-NEXT: 22: 41 a1 00 01 lui $1, 1 + ; CHECK-NEXT: 26: 40 60 00 02 bal 0x2e <foo+0x2e> +-; CHECK-NEXT: 2a: 30 21 04 69 addiu $1, $1, 1129 ++; CHECK-NEXT: 2a: 30 21 04 68 addiu $1, $1, 1128 + ; CHECK-NEXT: 2e: 00 3f 09 50 addu $1, $ra, $1 + ; CHECK-NEXT: 32: ff fd 00 00 lw $ra, 0($sp) + ; CHECK-NEXT: 36: 00 01 0f 3c jr $1 +@@ -27,7 +27,7 @@ + ; CHECK-NEXT: 56: fb fd 00 00 sw $ra, 0($sp) + ; CHECK-NEXT: 5a: 41 a1 00 01 lui $1, 1 + ; CHECK-NEXT: 5e: 40 60 00 02 bal 0x66 <foo+0x66> +-; CHECK-NEXT: 62: 30 21 04 5d addiu $1, $1, 1117 ++; CHECK-NEXT: 62: 30 21 04 5c addiu $1, $1, 1116 + ; CHECK-NEXT: 66: 00 3f 09 50 addu $1, $ra, $1 + ; CHECK-NEXT: 6a: ff fd 00 00 lw $ra, 0($sp) + ; CHECK-NEXT: 6e: 00 01 0f 3c jr $1 +@@ -39,7 +39,7 @@ + ; CHECK-NEXT: 86: fb fd 00 00 sw $ra, 0($sp) + ; CHECK-NEXT: 8a: 41 a1 00 01 lui $1, 1 + ; CHECK-NEXT: 8e: 40 60 00 02 bal 0x96 <foo+0x96> +-; CHECK-NEXT: 92: 30 21 04 2d addiu $1, $1, 1069 ++; CHECK-NEXT: 92: 30 21 04 2c addiu $1, $1, 1068 + ; CHECK-NEXT: 96: 00 3f 09 50 addu $1, $ra, $1 + ; CHECK-NEXT: 9a: ff fd 00 00 lw $ra, 0($sp) + ; CHECK-NEXT: 9e: 00 01 0f 3c jr $1 +@@ -51,7 +51,7 @@ + ; CHECK-NEXT: 10476: fb fd 00 00 sw $ra, 0($sp) + ; CHECK-NEXT: 1047a: 41 a1 00 01 lui $1, 1 + ; CHECK-NEXT: 1047e: 40 60 00 02 bal 0x10486 <foo+0x10486> +-; CHECK-NEXT: 10482: 30 21 04 01 addiu $1, $1, 1025 ++; CHECK-NEXT: 10482: 30 21 04 00 addiu $1, $1, 1024 + ; CHECK-NEXT: 10486: 00 3f 09 50 addu $1, $ra, $1 + ; CHECK-NEXT: 1048a: ff fd 00 00 lw $ra, 0($sp) + ; CHECK-NEXT: 1048e: 00 01 0f 3c jr $1 +diff --git a/llvm/test/CodeGen/Mips/micromips-gcc-except-table.ll b/llvm/test/CodeGen/Mips/micromips-gcc-except-table.ll +index 2b63aff01574..20d64fc216b7 100644 +--- a/llvm/test/CodeGen/Mips/micromips-gcc-except-table.ll ++++ b/llvm/test/CodeGen/Mips/micromips-gcc-except-table.ll +@@ -1,7 +1,7 @@ + ; RUN: llc -mtriple=mips-linux-gnu -mcpu=mips32r2 -mattr=+micromips -O3 -filetype=obj < %s | llvm-objdump -s -j .gcc_except_table - | FileCheck %s + + ; CHECK: Contents of section .gcc_except_table: +-; CHECK-NEXT: 0000 ff9b1501 0c011100 00110e1f 011f1800 ++; CHECK-NEXT: 0000 ff9b1501 0c001000 00100e1e 011e1800 + ; CHECK-NEXT: 0010 00010000 00000000 + + @_ZTIi = external constant ptr +diff --git a/llvm/test/DebugInfo/Mips/eh_frame.ll b/llvm/test/DebugInfo/Mips/eh_frame.ll +index 506e5b87892b..60d4dc76777e 100644 +--- a/llvm/test/DebugInfo/Mips/eh_frame.ll ++++ b/llvm/test/DebugInfo/Mips/eh_frame.ll +@@ -26,9 +26,9 @@ + ; CHECK-READELF-PIC-NEXT: R_MIPS_PC32 + ; CHECK-READELF-NEXT: .gcc_except_table + +-; EXCEPT-TABLE-STATIC: 0000 ff9b1501 0c011500 00150e23 01231e00 ...........#.#.. ++; EXCEPT-TABLE-STATIC: 0000 ff9b1501 0c001400 00140e22 01221e00 ...........".".. + ; EXCEPT-TABLE-STATIC: 0010 00010000 00000000 +-; EXCEPT-TABLE-PIC: 0000 ff9b1501 0c012d00 002d133f 013f2a00 ......-..-.?.?*. ++; EXCEPT-TABLE-PIC: 0000 ff9b1501 0c002c00 002c123e 013e2a00 ......,..,.>.>*. + ; EXCEPT-TABLE-PIC: 0010 00010000 00000000 ........ + + @_ZTIi = external constant ptr +-- +2.20.1 + |