counters: use AT&T inline asm syntax for older LLVM.

andjo403 · Nov 23, 2020 · 349183e · 349183e
1 parent efcb23f
commit 349183e
Showing 1 changed file with 27 additions and 8 deletions.
diff --git a/measureme/src/counters.rs b/measureme/src/counters.rs
@@ -525,10 +525,10 @@ mod hw {
  } else {
  asm!(
  // Dummy `cpuid(0)` to serialize instruction execution.
- "xor eax, eax",
+ "xor %eax, %eax", // Intel syntax: "xor eax, eax"
  "cpuid",
 
- "mov ecx, {rdpmc_ecx:e}",
+ "mov {rdpmc_ecx:e}, %ecx", // Intel syntax: "mov ecx, {rdpmc_ecx:e}"
  "rdpmc",
  rdpmc_ecx = in(reg) reg_idx,
  out("eax") lo,
@@ -539,6 +539,12 @@ mod hw {
  out("ecx") _,
 
  options(nostack),
+
+ // HACK(eddyb) LLVM 9 and older do not support modifiers
+ // in Intel syntax inline asm; whenever Rust minimum LLVM
+ // version becomes LLVM 10, remove and replace above
+ // instructions with Intel syntax version (from comments).
+ options(att_syntax),
  );
  }
  }
@@ -556,14 +562,14 @@ mod hw {
  unsafe {
  asm!(
  // Dummy `cpuid(0)` to serialize instruction execution.
- "xor eax, eax",
+ "xor %eax, %eax", // Intel syntax: "xor eax, eax"
  "cpuid",
 
- "mov ecx, {a_rdpmc_ecx:e}",
+ "mov {a_rdpmc_ecx:e}, %ecx", // Intel syntax: "mov ecx, {a_rdpmc_ecx:e}"
  "rdpmc",
- "mov {a_rdpmc_eax:e}, eax",
- "mov {a_rdpmc_edx:e}, edx",
- "mov ecx, {b_rdpmc_ecx:e}",
+ "mov %eax, {a_rdpmc_eax:e}", // Intel syntax: "mov {a_rdpmc_eax:e}, eax"
+ "mov %edx, {a_rdpmc_edx:e}", // Intel syntax: "mov {a_rdpmc_edx:e}, edx"
+ "mov {b_rdpmc_ecx:e}, %ecx", // Intel syntax: "mov ecx, {b_rdpmc_ecx:e}"
  "rdpmc",
  a_rdpmc_ecx = in(reg) a_reg_idx,
  a_rdpmc_eax = out(reg) a_lo,
@@ -577,6 +583,12 @@ mod hw {
  out("ecx") _,
 
  options(nostack),
+
+ // HACK(eddyb) LLVM 9 and older do not support modifiers
+ // in Intel syntax inline asm; whenever Rust minimum LLVM
+ // version becomes LLVM 10, remove and replace above
+ // instructions with Intel syntax version (from comments).
+ options(att_syntax),
  );
  }
  (
@@ -786,10 +798,17 @@ mod hw {
  let mut _tmp: u64 = 0;
  unsafe {
  asm!(
- "lock xadd qword ptr [{atomic}], {tmp}",
+ // Intel syntax: "lock xadd [{atomic}], {tmp}"
+ "lock xadd {tmp}, ({atomic})",
 
  atomic = in(reg) &mut atomic,
  tmp = inout(reg) _tmp,
+
+ // HACK(eddyb) LLVM 9 and older do not support modifiers
+ // in Intel syntax inline asm; whenever Rust minimum LLVM
+ // version becomes LLVM 10, remove and replace above
+ // instructions with Intel syntax version (from comments).
+ options(att_syntax),
  );
  }