[PATCH] D78931: [libunwind][RISCV] Track PC separately from RA

[Amanieu d'Antras via Phabricator via llvm-commits]

Amanieu updated this revision to Diff 260346.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D78931/new/

https://reviews.llvm.org/D78931

Files:
  libunwind/src/Registers.hpp
  libunwind/src/UnwindRegistersRestore.S
  libunwind/src/UnwindRegistersSave.S


Index: libunwind/src/UnwindRegistersSave.S
===================================================================
--- libunwind/src/UnwindRegistersSave.S
+++ libunwind/src/UnwindRegistersSave.S
@@ -1030,7 +1030,7 @@
 #  thread_state pointer is in a0
 #
 DEFINE_LIBUNWIND_FUNCTION(__unw_getcontext)
-  // x0 is zero
+  sd    x1, (8 * 0)(a0) // store ra as pc
   sd    x1, (8 * 1)(a0)
   sd    x2, (8 * 2)(a0)
   sd    x3, (8 * 3)(a0)
Index: libunwind/src/UnwindRegistersRestore.S
===================================================================
--- libunwind/src/UnwindRegistersRestore.S
+++ libunwind/src/UnwindRegistersRestore.S
@@ -1117,7 +1117,7 @@
 #endif
 
   // x0 is zero
-  ld    x1, (8 * 1)(a0)
+  ld    x1, (8 * 0)(a0) // restore pc into ra
   ld    x2, (8 * 2)(a0)
   ld    x3, (8 * 3)(a0)
   ld    x4, (8 * 4)(a0)
Index: libunwind/src/Registers.hpp
===================================================================
--- libunwind/src/Registers.hpp
+++ libunwind/src/Registers.hpp
@@ -3734,11 +3734,11 @@
 
   uint64_t  getSP() const         { return _registers[2]; }
   void      setSP(uint64_t value) { _registers[2] = value; }
-  uint64_t  getIP() const         { return _registers[1]; }
-  void      setIP(uint64_t value) { _registers[1] = value; }
+  uint64_t  getIP() const         { return _registers[0]; }
+  void      setIP(uint64_t value) { _registers[0] = value; }
 
 private:
-
+  // _registers[0] holds the pc
   uint64_t _registers[32];
   double   _floats[32];
 };
@@ -3773,7 +3773,7 @@
 
 inline uint64_t Registers_riscv::getRegister(int regNum) const {
   if (regNum == UNW_REG_IP)
-    return _registers[1];
+    return _registers[0];
   if (regNum == UNW_REG_SP)
     return _registers[2];
   if (regNum == UNW_RISCV_X0)
@@ -3785,7 +3785,7 @@
 
 inline void Registers_riscv::setRegister(int regNum, uint64_t value) {
   if (regNum == UNW_REG_IP)
-    _registers[1] = value;
+    _registers[0] = value;
   else if (regNum == UNW_REG_SP)
     _registers[2] = value;
   else if (regNum == UNW_RISCV_X0)


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