gdb: Allow prologue detection via symbols for Intel compilers.

The next-gen Intel Fortran compiler isn't flang-based, but emits
prologue_end in the same manner.  As do the newer Intel C/C++ compilers.
This allows prologue detection based on dwarf for all newer Intel compilers.
The cut-off version was not chosen for any specific reason other than the
effort to test this.

gdb/Changelog:
2021-04-08  Felix Willgerodt  <felix.willgerodt@intel.com>

    	* i386-tdep.c (i386_skip_prologue): Use symbol table to find the
    	prologue end for Intel compilers.
    	* amd64-tdep.c (amd64_skip_prologue): Likewise.
    	* producer.c (producer_is_icc_ge_19): New function.
    	* producer.h (producer_is_icc_ge_19): New declaration.

5 files changed, 33 insertions, 8 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 6fc98a7..e2fd912 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,13 @@
 2021-04-08  Felix Willgerodt  <felix.willgerodt@intel.com>
 
+	* i386-tdep.c (i386_skip_prologue): Use symbol table to find the
+	prologue end for Intel compilers.
+	* amd64-tdep.c (amd64_skip_prologue): Likewise.
+	* producer.c (producer_is_icc_ge_19): New function.
+	* producer.h (producer_is_icc_ge_19): New declaration.
+
+2021-04-08  Felix Willgerodt  <felix.willgerodt@intel.com>
+
 	* producer.c: (producer_is_icc): Update for new version scheme.
 	(producer_parsing_tests): Update names and expected results.
 	* producer.h: (producer_is_icc): Update comment accordingly.
diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index 47d0063..66a7c02 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -2527,13 +2527,14 @@ amd64_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc)
       struct compunit_symtab *cust = find_pc_compunit_symtab (func_addr);
 
       /* LLVM backend (Clang/Flang) always emits a line note before the
-	 prologue and another one after.  We trust clang to emit usable
-	 line notes.  */
+	 prologue and another one after.  We trust clang and newer Intel
+	 compilers to emit usable line notes.  */
       if (post_prologue_pc
 	  && (cust != NULL
 	      && COMPUNIT_PRODUCER (cust) != NULL
-	      && producer_is_llvm (COMPUNIT_PRODUCER (cust))))
-	return std::max (start_pc, post_prologue_pc);
+	      && (producer_is_llvm (COMPUNIT_PRODUCER (cust))
+	      || producer_is_icc_ge_19 (COMPUNIT_PRODUCER (cust)))))
+        return std::max (start_pc, post_prologue_pc);
     }
 
   amd64_init_frame_cache (&cache);
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index 2649fad..50fd276 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -1847,13 +1847,14 @@ i386_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc)
       struct compunit_symtab *cust = find_pc_compunit_symtab (func_addr);
 
       /* LLVM backend (Clang/Flang) always emits a line note before the
-	 prologue and another one after.  We trust clang to emit usable
-	 line notes.  */
+	 prologue and another one after.  We trust clang and newer Intel
+	 compilers to emit usable line notes.  */
       if (post_prologue_pc
 	  && (cust != NULL
 	      && COMPUNIT_PRODUCER (cust) != NULL
-	      && producer_is_llvm (COMPUNIT_PRODUCER (cust))))
-	return std::max (start_pc, post_prologue_pc);
+	      && (producer_is_llvm (COMPUNIT_PRODUCER (cust))
+	      || producer_is_icc_ge_19 (COMPUNIT_PRODUCER (cust)))))
+        return std::max (start_pc, post_prologue_pc);
     }
  
   cache.locals = -1;
diff --git a/gdb/producer.c b/gdb/producer.c
index 1cda48c..591509f 100644
--- a/gdb/producer.c
+++ b/gdb/producer.c
@@ -73,6 +73,18 @@ producer_is_gcc (const char *producer, int *major, int *minor)
   return 0;
 }
 
+/* See producer.h.  */
+
+bool
+producer_is_icc_ge_19 (const char *producer)
+{
+  int major, minor;
+
+  if (! producer_is_icc (producer, &major, &minor))
+    return false;
+
+  return major >= 19;
+}
 
 /* See producer.h.  */
 
diff --git a/gdb/producer.h b/gdb/producer.h
index 9cfccd6..d08062e 100644
--- a/gdb/producer.h
+++ b/gdb/producer.h
@@ -30,6 +30,9 @@ extern int producer_is_gcc_ge_4 (const char *producer);
    is NULL or it isn't GCC.  */
 extern int producer_is_gcc (const char *producer, int *major, int *minor);
 
+/* Check for Intel compilers >= 19.0.  */
+extern bool producer_is_icc_ge_19 (const char *producer);
+
 /* Returns true if the given PRODUCER string is Intel or false
    otherwise.  Sets the MAJOR and MINOR versions when not NULL.  */
 extern bool producer_is_icc (const char *producer, int *major, int *minor);