From f4e78131218efac2c17b9a150ebd3ac7868d0dbe Mon Sep 17 00:00:00 2001
From: Amanieu d'Antras <amanieu@gmail.com>
Date: Tue, 12 Jul 2022 22:54:47 +0200
Subject: [PATCH] Fix spans for asm diagnostics

Line spans were incorrect if the first line of an asm statement was an
empty string.
---
 compiler/rustc_builtin_macros/src/asm.rs |  4 ++--
 src/test/ui/asm/aarch64/srcloc.rs        |  7 +++++++
 src/test/ui/asm/aarch64/srcloc.stderr    | 14 +++++++++++++-
 src/test/ui/asm/x86_64/srcloc.rs         |  7 +++++++
 src/test/ui/asm/x86_64/srcloc.stderr     | 14 +++++++++++++-
 5 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/compiler/rustc_builtin_macros/src/asm.rs b/compiler/rustc_builtin_macros/src/asm.rs
index c95d7147176..47fd62d084e 100644
--- a/compiler/rustc_builtin_macros/src/asm.rs
+++ b/compiler/rustc_builtin_macros/src/asm.rs
@@ -534,8 +534,8 @@ fn expand_preparsed_asm(ecx: &mut ExtCtxt<'_>, args: AsmArgs) -> Option<ast::Inl
 
     let mut template_strs = Vec::with_capacity(args.templates.len());
 
-    for template_expr in args.templates.into_iter() {
-        if !template.is_empty() {
+    for (i, template_expr) in args.templates.into_iter().enumerate() {
+        if i != 0 {
             template.push(ast::InlineAsmTemplatePiece::String("\n".to_string()));
         }
 
diff --git a/src/test/ui/asm/aarch64/srcloc.rs b/src/test/ui/asm/aarch64/srcloc.rs
index 040d4df546f..dbb6cbb9437 100644
--- a/src/test/ui/asm/aarch64/srcloc.rs
+++ b/src/test/ui/asm/aarch64/srcloc.rs
@@ -118,5 +118,12 @@ fn main() {
         //~^^^^^^^^^^ ERROR: unrecognized instruction mnemonic
         //~^^^^^^^ ERROR: unrecognized instruction mnemonic
         //~^^^^^^^^ ERROR: unrecognized instruction mnemonic
+
+        asm!(
+            "",
+            "\n",
+            "invalid_instruction"
+        );
+        //~^^ ERROR: unrecognized instruction mnemonic
     }
 }
diff --git a/src/test/ui/asm/aarch64/srcloc.stderr b/src/test/ui/asm/aarch64/srcloc.stderr
index f8b645c23f5..2e17b60b912 100644
--- a/src/test/ui/asm/aarch64/srcloc.stderr
+++ b/src/test/ui/asm/aarch64/srcloc.stderr
@@ -274,5 +274,17 @@ note: instantiated into assembly here
 LL | invalid_instruction4
    | ^
 
-error: aborting due to 23 previous errors
+error: unrecognized instruction mnemonic
+  --> $DIR/srcloc.rs:125:14
+   |
+LL |             "invalid_instruction"
+   |              ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:4:1
+   |
+LL | invalid_instruction
+   | ^
+
+error: aborting due to 24 previous errors
 
diff --git a/src/test/ui/asm/x86_64/srcloc.rs b/src/test/ui/asm/x86_64/srcloc.rs
index 8a21d759772..1135ad2e1c6 100644
--- a/src/test/ui/asm/x86_64/srcloc.rs
+++ b/src/test/ui/asm/x86_64/srcloc.rs
@@ -120,5 +120,12 @@ fn main() {
         //~^^^^^^^^^^ ERROR: invalid instruction mnemonic 'invalid_instruction2'
         //~^^^^^^^ ERROR: invalid instruction mnemonic 'invalid_instruction3'
         //~^^^^^^^^ ERROR: invalid instruction mnemonic 'invalid_instruction4'
+
+        asm!(
+            "",
+            "\n",
+            "invalid_instruction"
+        );
+        //~^^ ERROR: invalid instruction mnemonic 'invalid_instruction'
     }
 }
diff --git a/src/test/ui/asm/x86_64/srcloc.stderr b/src/test/ui/asm/x86_64/srcloc.stderr
index b62c8948289..8899c1b916b 100644
--- a/src/test/ui/asm/x86_64/srcloc.stderr
+++ b/src/test/ui/asm/x86_64/srcloc.stderr
@@ -286,5 +286,17 @@ note: instantiated into assembly here
 LL | invalid_instruction4
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 23 previous errors; 1 warning emitted
+error: invalid instruction mnemonic 'invalid_instruction'
+  --> $DIR/srcloc.rs:127:14
+   |
+LL |             "invalid_instruction"
+   |              ^
+   |
+note: instantiated into assembly here
+  --> <inline asm>:5:1
+   |
+LL | invalid_instruction
+   | ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 24 previous errors; 1 warning emitted